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Full text of "The modern clock; a study of time keeping mechanism; its construction, regulation, and repair"

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The Modern Clock 



A Study of Time Keeping Mechanism; 

Its Construction, Regulation 

and Repair. 



BY WARD L. GOODRICH 

Author of the Watchmaker's Lathe, Its Use and Abuse, 

BOSTON COLLEGE LIBRaKY 
OHJC8TNUT HILL, MASS. 



WITH NUMEROUS ILLUSTRATIONS AND DIAGRAMS 



CHICAGO 
Hazlitt 8c Walker, Publishers 
1905 



.^^n 



Copyrighted 

1905 

BY HAZI.ITT & WALKER. 



CHAPTER I. 

THE NECESSITY FOR BETTER SKILL AMONG CLOCKMAKERS 

The need for information of an exact and reliable char- 
acter in regard to the hard worked and much abused clock 
has, we presume, been felt by every one who entered the 
trade. This information exists, of course, but it is scat- 
tered through such a wide range of pubHcations and is found 
in them in such a fragmentary form that by th^ time a 
workman is sufficiently acquainted with the literature of the 
trade to know where to look for such information he no 
longer feels the necessity of acquiring it. 

The continuous decrease in the prices of watches and the 
consequent rapid increase in their use has caused the neglect 
of the pendulum timekeepers to such an extent that good 
clock men are very scarce, while botches are universal. 
When we reflect that the average "life' of a v/orker at the 
bench is rarely mere than twenty years, we can readily see 
that information by verbal instruction is rapidly being lost, 
as each apprentice rushes through clock work as hastily as 
possible in order to do watch work and consequently each 
"watchmaker" knows less of clocks than his predecessor 
and is therefore less fitted to instruct apprentices in his 
turn. 

The striking clock will always continue to be the time- 
keeper of the household and we are still dependent upon the 
compensating pendulum, in conjunction with the fixed stars, 
for the basis of our time-keeping system, upon which our 
commeicial and legal calendars and the movements of our 
ships and railroad trains depend, so that an accurate knowl- 
edge of its construction and behavior forms the essential 

3. •.■ ..-..-:' 



4. THE MDDERN CEOCK. 

basis of the largest part of our business and social system?, 
while the watches for which it is slighted are themselves 
regulated , and adjusted at the factories by the compensated 
pendulum. 

The rapid increase in the dissemination of "standard 
time"*' and the com.pulsory use of watches having a maxi- 
mum variation of five seconds a week by railway employes 
has so increased the standard of accuracy dem.anded by the 
general public that it is no longer possible to make careless 
work "go" with them, and, if they accept it at all, they 
are apt to make serious deductions from their estimate of 
the watchmaker's skill and immediately transfer their cus- 
tom to some one who is more thorough. 

The apprentice, when he first gets an opportunity to ex- 
amine a clock movement, usually considers it a very myste- 
rious machine. Later on, if he handles many clocks of the 
simple order, he becomes tolerably familiar with the time 
train ; but he seldorn becomes confident of his ability regard- 
ing the striking part, the alarm and the escapement, chiefly 
because the employer and the older workmen get tired of 
telling him the same things repeatedly, or because they were 
similarly treated in their youth, and consider clocks a nui- 
sance, any how, never having learned clock work thorough- 
ly, and therefore being unable to appreciate it. In conse- 
quence of such treatment the boy makes a few spasmodic 
efforts to learn the portions of the business that puzzle him, 
and then gives it up, and thereafter does as little as possible 
to clocks, but begs continually to be put on watch work. 

We know of a shop where two and sometimes three 
workmen (the best in the shop, too) are constantly employed 
upon clocks which country jewelers have failed to repair. 
If clock work is dull they will go upon watch work (and 
they do good work, too), but they enjoy the clocks and will 
do them in preference to watches, claiming that there is 
greater variety and more interest in the work than can be 
found in fitting factory made material into watches, which 



TPIE MODERN CLOCK. 5 

consist of a time train only. Two of these men have be- 
come famous, and are frequently sent for to take care of 
complicated clocks, with musical and mechanical figure at- 
tachments, tower, chimes, etc. The third is much younger, 
but is rapidly perfecting himself, and is already competent 
to rebuild minute repeaters and other sorts of the finer 
kinds of French clocks. He now totally neglects watch 
work, saying that the clocks give him mort money and 
more fun. 

We are confident that this would be also the case with 
many another American youth if he could find some one 
to patiently instruct him in the few indispensable facts which 
lie at the bottom, of so much that is mysterious and from 
which he now turns in disgust. The object of these arti- 
cles is to explain to the apprentice the mysteries of pendu- 
lums, escapements, gearing of trains, and the whole tech- 
nical scheme of these measurers of time, in such a way that 
hereafter he may be able to answer his own questions, be- 
cause he will be familiar with the facts on which they 
depend. 

Many workmen in the trade are already incompetent to 
teach clockwork to anybody, owing to the slighting process 
above referred to ; and the frequent demands for a book on 
clocks have therefore induced the writer to undertake its 
compilation. Works on the subject — nominally so, at least 
— are in existence, but it will generally be found on exami- 
nation that they are written by outsiders, not by workmen, 
and that they treat the subject historically, or from the 
standpoint of the artistic or the curious. Any information 
regarding the mechanical movements is fragm.entary, if 
found in them at all, and they are better fitted for the amuse- 
ment of the general public than for the youth or man who 
wants to know "how and why." These facts have im- 
pelled the writer to ignore history and art in considering 
the subject; to treat the clock as an existing mechanism 
which must be understood and made to perform its func- 



THE MODERN CLOCK. 



tions correctly ; and to consider cases merely as housings 
of mechanism, regardless of how beautiful, strange or com- 
monplace those housings may be. 

We have used the word "compile" advisedly. The writer 
has no new ideas or theories to put forth, for the reason 
that the mechanism we are considering has during the last 
six hundred years had its mathematics reduced to an exact 
science; its variable factors of material and mechanical 
movements developed according to the laws of geometry and 
trigonometry ; its defects observed and pointed out ; its per- 
formances checked and recorded. To gather these facts, 
illustrate and explain them, arrange them in their proper 
order, and point out their relative importance in the whole 
sum of what we call a clock, is therefore all that will be at- 
tempted. In doing this free use has been made of the ob- 
servations of Saunier, Reid, Glasgow, Ferguson, Britten, 
Riefler and others in Europe and of Jerome, Playtner, Finn, 
Learned, Ferson, Howard and various other Americans. 
The work is therefore presented as a compilation, which it 
is hoped will be of service in the trade. 

In thus studying the modern American clocks, we use the 
word American in the sense of ownership rather than origin, 
the clocks which come to the American workmen to-day 
have been made in Germany, France, England and America. 

The German clocks are generally those of the Schwartz- 
wald (or Black Forest) district, and differ from others in 
their structure, chiefly in the following particulars: The 
movement is supported by a horizontal seat-board in the 
upper portion of the case. The wooden trains of many of 
the older type instead of being supported by plates are held 
in position by pillars, and these pillars are held in position 
by top and bottom boards. In the better class of wooden 
clocks the pivot holes in the pillars are bushed with brass 
tubing, while the movement has a brass *scape wheel, steel 
wire pivots and lantern pinions of wood, with steel trun- 



THE MODERN CLOCK. 7 

dies. In all these clocks the front pillars are friction tight, 
and are the ones to be removed when taking down the 
trains. Both these and the modern Swartzwald brass move- 
ments use a sprocket wheel and chain for the weights and 
have exposed pendulums and weights. 

The French clocks are of two classes, pendules and car- 
riage clocks, and both are liable to develop more hidden 
crankiness and apparently causeless refusals to go than, 
ever occurred to all the English, German and American 
clocks ever put together. There are many causes for this^ 
and unless a mxan is very new at the business he can tell 
stories of perversity, that w^ould make a timid apprentice 
want to quit. Yet the French clocks, when they do go, are 
excellent time-keepers, finely finished, and so artistically de- 
signed that they make their neighbors seem very clumsy by 
comparison. They are found in great variety, time, half- 
hour and quarter-hour strike, musical and repeating clocks 
being a few of the general varieties. The pendulums are 
very short, to accommodate themselves to the artistic needs 
of the cases, and nearly all have the snail strike instead of 
the count wheel. The carriage clocks have v/atch escape- 
ments of cylinder or lever form, and the escapement is fre- 
quently turned at right angle by means of bevel gears, or 
contrate wheel and pinion, and placed on top of the move- 
ment. 

The English clocks found in America are generally of 
the ''Hall" variety, having heavy, well finished movements, 
with seconds pendulum and frequently with calendar and 
chime movements. They, like the German, are generally 
fitted with weights instead of springs. There are a few 
English carriage clocks, fitted with springs and fuzees, 
though most of them, like the French, have springs fitted in 
going barrels. 

The American clocks, with which the apprentice will nat- 
urally have most to do, may be roughly divided into time. 



8 THE MODERN CLOCK. 

time alarm, tim.e strike, time strike alarm, time calendar 
and electric winding. The American factories generally 
each make about forty sizes and styles of movements, and 
case them in many hundreds of different ways, so that the 
workman will frequently find the same movement in a large 
number of clocks, and he will soon be able to determine from 
the characteristics of the movement what factory made the 
clock, and thus be able to at once turn to the proper cata- 
logue if the name of the maker be erased, as frequently 
happens. 

This comparative study of the practice of different facto- 
ries will prove very interesting, as the movement comes to 
the student after a period of prolonged and generally se- 
vere use, which is calculated to bring out any existing de- 
fects in construction or workmanship ; and having all makes 
of clocks constantly passing through his hands, each ex- 
hibiting a characteristic defect more frequently than any 
other, he is in a much better position to ascertain the merits 
and defects of each maker than he v/ould be in any factory. 

Having thus briefly outlined the kinds of machinery used 
in measuring time, we will now turn our attention to the 
examination of the theoretical and mechanical construction 
of the various parts. 

The man who starts out to design and build a clock will 
find himself limited - in three particulars : It must run a 
specified time; the arbor carrying the minute hand must 
turn once in each hour ;. the pendulum must be short enough 
to go in the case. Two of these particulars are changeable 
according to circumstances ; the length of time run may be 
thirty hours, eight, thirty, sixty or ninety days. The pendu- 
lum may be anywhere from four inches to fourteen feet, and 
the shorter it is the faster it will go. The one definite 
point in the time train is that the minute hand must turn 
once in each hour. We build or alter our train from this 
point both ways, back through changeable intermediate 



THE MODERN CLOCK. 



wheels and pinions to the spring or weight forming the 
source of power, and forward from it through another 
changeable series of wheels and pinions to the pendulum. 
Now as the pendulum governs the rate of the clock we will 
commence with that and consider it independently. 



CHAPTER II. 

' THE NATURAL LAWS GOVERNING PENDULUMS. 

Length of Pendulum. — A pendulum is a falling body 
and as such is subject to the laws which govern falling bod- 
ies. This statement may not be clear at first, as the pendu' 
lum generally moves through such a small arc that it does 
not appear to be falling. Yet if we take a pendulum and 
raise the ball by swinging it up tmtil the ball is level with the 
point of suspension, as in Fig. i, and then let it go, we 



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Fig. 1. Dotted lines show path of pendulum. 

shall see it fall rapidly until it reaches its lowest point, and 
then rise until it exhausts the momentum it acquired in fall- 
ing, when it will again fall and rise again on the other side ; 
this process will be repeated through constantly smaller 
arcs until the resistance of the air and that of the pendulum 
spring shall overcome the other forces which operate to 
keep it in motion and it finally assumes a position of rest 
at the lowest point (nearest the earth) which the pendulum 

ID 



THE MODERN CLOCK. II 

rod will allow it to assume. When it stops, it will be in 
line between the center of the earth (center of gravity) 
and the fixed point from which it is suspended. True, the 
pendulum bob, when it falls, falls under control of the 
pendulum rod and has its actions modified by the rod ; but 
it falls just the same, no matter how small its arc of motion 
may be, and it is this influence of gravity — that force which 
makes any free body move toward the earth's center — 
which keeps the pendulum constantly returning to its low- 
est point and which governs very largely the time taken in 
moving. Hence, in estimating the length of a pendulum, 
we must consider gravity as being the prime mover of our 
pendulum. 

The next forces to consider are mass and weight, which, 
when put in motion, tend to continue that motion indefinitely 
unless brought to rest by other forces opposing it. This is 
known as momentum. A heavy bob will swing longer 
than a light one, because the momentum stored up during 
its fall will be greater in proportion to the resistance which 
it encounters from the air and the suspension spring. 

As the length of the rod governs the distance through 
which our bob is allowed to fall, and also controls the direc- 
tion of its motion, we must consider this motion. Refer- 
ring again to Fig. i, we see that the bob moves along the 
circumference of a circle, with the rod acting as the radius 
of that circle ; this opens up another series of facts. The 
circumference of a circle equals 3.1416 times its diameter, 
and the radius is half the diameter (the radius in this case 
being the pendulum rod). The areas of circles are propor- 
tional to the squares of their diameters and the circumfer- 
ences are also proportional to their areas. Hence, the 
lengths of the paths of bobs moving along these circumfer- 
ences are in proportion to the squares of the lengths of the 
pendulum rods. This is why -a pendulum of half the length 
will oscillate four times as fast. 

Now we will apply these figures to our pendulum. A 



12 THE MODERN CLOCK. 

body falling in vacuo, in London, moves 32.2 feet in one 
second. This distance Kas by common consent among 
mathematicians been designated as g. The circumference 
of a circle equals 3.416 times its diameter. This is repre- 
sented as 77- Now, if we call the time t, we shall have the 
formula : 



'Vi 



^ 



Substituting the time, one second, for t, and doing the same 
with the others, we shall. have: 

CJ2.2 ft. r ^ r 

I = — ^^= c>.26i6 feet. 

(3.i4i6)» ^ 

Turning this into its equivalent in inches by multi- 
plying by 12, we shall have 39.1393 inches as the length of 
a one-second pendulum at London. 

Now, as the force of gravity varies somewhat with its 
distance from the center of the earth, we shall find the value 
of g in the above formula varying slightly, and this will 
give us slightly different lengths of pendulum at different 
places. These values have been found to be as follows : 

Inches. 

The Equator is 3g 

Rio dc Janiero 39-01 

Madras 3(;'.02 

New York , 39. 10x2 

Paris 39.13 

London 39-14 

Edinbv.rsh 39.15 

Greenland 39-20 

North and South Pole 39.206 

Now, taking another look at our formula, we shall see 
that we may get the length of any pendulum by multiply- 
n^^TT (which is 3.1416) by the square of the time required: 
To find the length of a pendulum to beat three seconds : 

3' = 9- 39-1393x9 = 352.2537 inches = 29.3544 feet. 
A pendulum beating two-thirds of a second, or 90 beats: 



THE MODERN CLOCK. I3 

(2). ^ 4. . 39-1393 X 4 ^ 17.3953 inches. 
A pendulum beating half-seconds or 120 beats : 
(,^,^,. 39-.393X. ^^_^3^S inches. 

Center of Oscillation. — Having now briefly consid- 
ered the basing facts governing the time of oscillation of 
the pendulum, let us examine it still further. The pendu- 
lum shown in Fig. i has all its weight in a mass at its end, 
but we cannot make a pendulum that way to run a clock, 
because of physical limitations. We shall have to use a 
rod stiff enough to transmit power from the clock move- 
ment to the pendulum bob and that rod will weigh some- 
thing. If we use a compensated rod, so as to keep it the 
same length in varying temperature, it may weigh a good 
deal in proportion to the bob. How will this affect the pen- 
dulum ? 

If we suspend a rod from its upper end and place along- 
side of it our ideal pendulum, as in Fig. 2, we shall find that 
they will not vibrate in equal times if they are of equal 
lengths. Why not? Because when the rod is swinging 
(being stiff) a part of its weight rests upon the fixed point 
of suspension and that part of the rod is consequently not 
entirely subject to the force of gravity. Now, as the time 
in which our pendulum will swing depends upon the dis- 
tance of the effective center of its mass from the point of 
suspension, and as, owing to the difference in construction, 
the center of mass of one of our pendulums is at the center 
of its ball, while that of the other is somewhere along the 
rod, they will naturally swing in different times. 

Our other pendulum (the rod) is of the same size all the 
way up and the center of its effective mass would be the 
center of its weight (gravity) if it were not for the fact 
which we stated a moment ago that part of the weight is 
upheld and rendered ineft'ective by the fixed support of the 



H 



THE MODERN CLOCK. 



f-A- 



6 



A^ 







a 



Fig. 2. Two pendulums of equal length but unequal vibration. B, cen- 
ter of oscillation for both pendulums. 



y ^ 
• y 

y y 

y y 



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Fig. 3. 



THE MODERN CLOCK. 



^5 



pendulum rod, all the while the pendulum is not in a vertical 
position. If we support the rod in a horizontal position^ as 
in Fig. 3, by holding up the lower end, the point of sus- 
pension, A, will support half the weight of the rod ; if we 
hold it at 45 degrees the point of suspension will hold less 
than half the weight of the rod and more of the rod will 
be affected by gravity; and so on down until we reach the 
vertical or up and down position. Thus we see that the 
force of. gravity pulling on our pendulum varies in its ef- 
fects according to the position of the rod and consequently 
the effective center of its mass also varies with its position 
and we can only calculate what this mean (or average) po- 
sition is by a long series of calculations and then taking an 
average of these results. 

We shall find it simpler to measure the time of swing of 
the rod which we will do by shortening our ball and cord 
until it will swing in the same time as the rod. This will be 
at about two-thirds of the length of the rod, so that the 
effective length of our rod is about two-thirds of its real 
length. This effective length, which governs the time of 
vibration, is called the theoretical length of the pendulum 
and the point at which it is located is called its center of 
oscillation. The distance from the center of oscillation to 
the point of suspension is called the theoretical length of the 
pendulum and is always the distance which is given in all 
tables of lengths of pendulums. This length is the one 
given for two reasons : First, because, it is the time-keeping 
length, which is what we are after, and second, because, as 
we have just seen in Fig. 3, the real length of the pendulum 
increases as more of the weight of the instrument is put into 
the rod. This explains why the heavy gridiron compensa- 
tion pendulum beating seconds so common in regulators and 
which measures from. 56 to 60 inches over all, beats in the 
same time as the wood rod and lead bob measuring 45 
inches over all, while one is apparently a third longer than 
the other. 



i6 



THE MODERN CLOCK. 



Table Showing the Length of a Simple Pendulum 

That performs in one hour any given number of oscillations, from r 
to 20,000, and the variation in this length that will occasion a difference 
of I minute in 24 hours. 

Calculated by E. Gourdin. 



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Length 
te in 24 
meters. 


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1' 

B 


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%\ 


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H 


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>^S 







>ex 


20,000 


32.2 


G.04 


13,200 


73.9 


0.10 


8,200 


191.5 


0.26 


19,000 


35.7 


0.05 


13,100 


75.1 


0.10 


8,100 


196.3 


0.27 


18,000 


39.8 


0.05 


13,000 


76.2 


0.10 


8,000 


201.3 


o.2r 


17,900 


40.2 


0.06 


12,900 


77.4 


0.11 


7,900 


206.4 


0.28 


17,800 


40.7 


0.06 


12,800 


78.6 


0.11 


7,800 


211.7 


0.29 


17,700 


41.1 


0.06 


12,700 


79.9 


0.11 


7,700 


217.3 


0.30 


17.fi00 


41.6 


0.06 


12,600 


81.1 


0.11 


7,600 


223.0 


0.3<> 


17.500 


42.1 


0.06 


12,5110 


82.4 


0.11 


7,500 


229.0 


0.31 


17,400 


42.4 


0.06 


12,400 


83.8 


0.11 


7,400 


235.2 


0.3* 


17,300 


43.0 


0.06 


12,300 


85.1 


0.12 


7,300 


241.7 


0.3* 


17,200 


43.5 


0.06 


12,200 


86.5 


0.12 


7,200 


248.5 


0.34 


17.100 


44.0 


0.06 


12,100 


88.0 


0.12 


7,100 


255.7 


0.3* 


17,000 


44.6 


0.06 


12,000 


89.5 


0.12 


7,000 


262.9 


0.3& 


16,900 


45.1 


0.06 


11,900 


91.0 


0.12 


6,900 


270.5 


o.sr 


16,800 


45.7 


0.06 


11,800 


92.5 


0.13 


6,800 


278.6 


0.3» 


16,700 


46.3 


0.06 


11,700 


94.1 


0.13 


6,700 


286.9 


0.S» 


16.600 


46.7 


0.07 


11,600 


95.7 


0.13 


6,600 


295.7 


0.40 


16,500 


47.3 


0.07 


11,500 


97.4 


0.13 


6,500 


304.9 


0.41 


16,400 


47.9 


0.07 


11,400 


99.1 


0.13 


6,400 


314.5 


0.4* 


16,300 


48.5 


0.07 


11,300 


100.9 


0.14 


6,300 


324.5 


0.44 


16,200 


49.1 


0.07 


11,2U0 


102.7 


0.14 


6,200 


335.1 


0.46 


16,100 


49.7 


0.07 


11,100 


104.5 


0.14 


6,100 


34R.2 


o.4r 


16,0<iO 


50.0 


0.07 


11,000 


106.5 


0.14 


6,C00 


357.8 


0.4* 


15,900 


51.0 


0.07 


10,900 


108.4 


0.15 


5,900 


370.0 


0.50 


15,800 


51.6 


0.07 


10,800 


110.5 


0.15 


5,800 


382.9 


0.5* 


15,7ti0 


52.3 


0.07 


10,700 


112.5 


0.15 


5,700 


396.4 


0.54 


15.600 


52.9 


0.07 


10,600 


114.6 


0.16 


5,600 


410.7 


0.50 


15,500 


53.6 


0.07 


10,500 


116.8 


0.16 


5,500 


425.^ 


0.58^ 


15,400 


54.3 


0.08 


10,400 


119.1 


0.16 


5,400 


440.1 


0.6O 


15,300 


55.0 


0.08 


11,300 


111.4 


0.17 


5,300 


458.5 


0.6* 


15,200 


55.7 


0.08 


10,200 


123.8 


0.17 


5,200 


476.3 


0.6S 


15,100 


56.5 


0.08 


10,100 


126.3 


0.17 


5,100 


495.2 


o.er 


15,000 


57.3 


0.08 


10,000 


128.8 


0.18 


5,000 


515.2 


0.70 


14,900 


58.0 


0.08 


9,900 


131.4 


0.18 


4,900 


536.5 


0.7* 


14,800 


58.8 


0.08 


9,800 


134.1 


0.18 


4,800 


559.1 


0.78 


14,700 


59.6 


0.08 


9,700 


136.9 


0-19 


4,700 


583.1 


0.70 


14,600 


60.4 


0.08 


9,600 


139.8 


0.19 


4,600 


• 608.7 


O.Si 


14,500 


61.3 


0.08 


9,500 


142.7 


0.19 


4,500 


636.1 


0.8R 


14,400 


68.1 


0.09 


9,400 


145.8 


0.20 


4,400 


665.3 


0.90 


141300 


63.0 


0.09 


9,300 


148.9 


0-20 


4,300 


696.7 


0.9S 


14,200 


63.9 


0.09 


9,200 


152.2 


0.21 


4,200 


730.2 


0.90 


14,100 


64.8 


0.09 


9,100 


155.5 


0-21 


4,100 


766.2 


1.04 


14,000 


65.7 


0.09 


9,noo 


159.0 


0.22 


4,000 


805.0 


1.00 


13,900 


66.7 


0.09 


8,900 


162.6 


0.22 


3,950 


825.5 


1.1* 


13,800 


67.6 


0.09 


8,800 


IK6.3 


0.23 


3,900 


846.8 


1.15 


13.700 


68-6 


0.(19 


8,700 


170.2 


0.2:3 


3,850 


869.0 


l.ld 


13,600 


69.6 


0.09 


8,600 


173.7 


0.24 


S,800 


892.0 


1.21 


13,500 


70.7 


0.09 


8,500 


178.3 


0.24 


3,750 


915.9 


1.2s 


13,400 


71.7 


0.10 


8,400 


182.5 


0.25 


3,700 


940.1 


L28 


13,300 


72.8 


0.10 


8,300 


187.0 


0.25 


3,650 


966.8 


1.31 



THE MODERN CLOCK. 

Table of the Length of a Simple Pendulum, 

(continued.) 



CO 

§ 

■J 


j2 


To Produce in 
24 Hours 


1 




To Produce 


in 24 Hours 


i: 




1 Minute. 


% 




1 M 


nute. 


1 3 






u 


Length 
in 






2« 


^i 


t^t 






<= i 


si 


^%% 


A^ 


'° 'z 


Meters. 


Loss, 


Gain, 


^ " 


n 


o| S 


%r^ 


1 "- 




Lengthen by 


Shorten by 


a 

3 


:a 






E 

3 


- 


Meters. 


Meters. 


"A 




^^ 


C/3S 


^ 








3 600 


0.9939 


1.38 


1.32 


1900 


3.5G8 


0.0950 


0.0048 


3,550 


1.0221 


1,42 


1.36 


1,800 


3 975 


0055 


0.0053 


3,500 


1.0515 


1.46 


1.40 


1,700 


4.457 


0.0062 


-0.0059 


3,450 


1.0822 


1.50 


144 


1;600 


5.031 


0070: 


0.00(^7 


3.400 


1.1143 


1.55 


1.48 


1,500 


5 725 


0.01^80 


0.0076 


3,350 


1.1477 


1.60 


1.53 


1,400 


6.572 


0.0091 


0.0087 


3,300 


1.1828 


1.64 


1.57 


1,300 


7.6-22 


0.0106 


0.0101 


3.250 


1.2194 


1.69 


1.62 


1,200 


8.945 


0124 


0.0119 


3,200 


1.2578 


175 


1.67 


1,100 


10.645 


0.0148 


0.0142 


3,150 


1.2981 


1.80 


1.73 


1,000 


12.880 


0.0179 


0.0171 


3,100 


1.3403 


1.86 


178 


900 


15 902 


0.0221 


0.0211 


3,050 


1.3846 


1.93 


1.84 


800 


20.126 


0280 


0.0268 


3,U00 


1.4312 


1.99 


190 


700 


26.287 


0365 


0.0350 


2.900 


1.5316 


2.13 


2.04 


600 


35 779 


00497 


0.0476 


2.800 


1.6429 


2.28 


218 


500 


51 521 


0.0716 


0.0685 


2.700 


1.7669 


2.46 


2 35 


400 


SO 502 


0.1119 


0.1071 


2,600 


19054 


2.65 


2 53 


30© 


143115 


0.1989 


0.1903 


2,500 


2.0609 


2 87 


2.74 


200 


322 008 


0.4476 


0.4282 


2,400 


2.2362 


3.11 


297 


100 


1,283.034 


1.7904 


1.7131 


2,800 


2.4349 


3.38 


3 24 


60 


3,577.871 


4 9732 


4.7586 


2,200 


2 6612 


3.70 


8.54 


50 


5,152.135 


7.1613 


6.8521 


2,100 


2.9207 


4.06 


3 88 


1 


12,880,337.930 


17,9036700 


17,130.8500 


2,000 


32201 


4.48 


4.28 











In the foregoing tables all dimensions are given in meters 
and millimeters. If it is desirable to express them in feet 
and inches, the necessary conversion can be at once effected 
in any given case by employing the following conversion 
table, which will prove of considerable value to the watch- 
maker for various purposes : 



Ii THE MODERN CLOCK. 

Conversioa Table of Inches, Millimeters and French Lines. 



Inches expressed in 


MUlimeters 


expressed 


French Lines expressed 


Millimeters and French 


in Inches and French 


in Inches and 


Lines. 


Lines. 


Millimeters. 


i 


Equal to 


1 


Equal to 




Equal to 


u 












^ 






M 


Millimeters 


French 
Lines. 


S 


Inches. 


French 
Lines. 


fa 


Inches. 


Millimeters 


1 


25 39954 


11.25951 


1 


0.0393708 


0.44329 


1 


0.088414 


2.25583 


^ 


50.79908 


22.51903 


2 


0.0787416 


0.88659 


2 
8 


0.177628 
0266441 


4.51166 
6.76749 


3 


76.19862 


33.77854 


3 


0.1181124 


1.32989 


4 


0.355255 


9.02332 


4 


101.59816 


45.03806 


4 


0.1574832 


1.77318 


5 


0.444069 


11.27915 


5 


126.99771 


56.29757 


5 


0.1968539 


2.21648 


6 


0.532883 


13.53497 


6 


162.39725 


67.55709 


6 


0.2362247 


2.65978 


7 


0.621697 


15.79080 


7 


177.79679 


78 81660 


7 


0.2755955 


3.10307 


8 
9 


0.710510 
0.799324 


18.04663 
20.30246 


8 


203 19633 


90.07612 


8 


0.3149664 


3.54637 


10 


0.888138 


22.55829 


9 


22859587 


10133563 


9 


0.3543371 


3 98966 


11 


0.976952 


2481412 


10 


253.99541 


112.59515 


10 


0.3937079 


4.43296 


12 


1.065766 27.06995 



Center of Gravity. — The watchmaker is concerned only 
with the theoretical or timekeeping lengths of pendulums, 
as his pendulum comes to him ready for use; but the clock 
maker who has to build the pendulum to fit not only the 
movement, but also the case, needs to know more about it, 
as he must so distribute the weight along its length thai it 
may be given a length of 6o inches or of 44 inches, or any- 
thing between them, and still beat seconds, in the case of a 
regulator. He must also do the same thing in other clocks 
having pendulums which beat other numbers than 60. 
Therefore he must know the center of his weights ; this is 
called the center of gravity. This center of gravity is often 



THE MODERN CLOCK. 



19 



confused by many with the center of oscillation as its real 
purpose is not understood. It is simply used as a starting 
point in building pendulums, because there must be a start- 
ing point, and this point is chosen because it is always pres- 
ent in every pendulum and it is convenient to work both 
ways from the center of weight or gravity. In Fig. 2 we 
have two pendulums, in one of which (the ball and string) 
the center of gravity is the center of the ball and the center 
of oscillation is also at the center (practically) of the ball. 
Such a pendulum is about as short as it can be constructed 
for any given number of oscillations. The other (the rod) 
has its center of gravity manifestly at the center of the rod, 
as the rod is of the same size throughout ; yet we found by 
comparison with the other that its center of oscillation was 
at two-thirds the length of the rod, measured from the point 
of suspension, and the real length of the pendulum was con- 
sequently one-half longer than its time keeping length, which 
is at the center of oscillation. This is farther apart than 
the center of gravity and oscillation will ever get in actual 
practice, the most extreme distance in practice being that 
of the gridiron pendulum previously mentioned. The cen- 
ter of gravity of a pendulum is found at that point at which 
the pendulum can be balanced horizontally on a knife edge 
and is marked to measure from when cutting off the rod. 

The center of oscillation of a compound pendulum must 
always be below its center of gravity an amount depending 
upon the proportions of weight between the rod and the bob. 
Where the rod is kept as light as it should be in proportion 
to the bob this difference should come well within the lim- 
its of the adjusting screw. In an ordinary plain seconds 
pendulum, without compensation, with a bob of eighteen 
or twenty pounds and a rod of six ounces, the difference in 
the two points is of no practical account, and adjustments 
for seconds are within the screw of any ordinary pendulum, 
if the screw is the right length for safety, and the adjusting 
nut is placed in the middle of the length of the screw threads 



20 THE MODERN CLOCK. 

when the top of the rod is cut off, to place the suspen- 
sion spring by measurement from the center of gravity as 
has been already described ; also a zinc and iron compensa- 
tion is within range of the screw if the compensating rods 
are not made in undue weight to the bob. The whole 
v/eight of the compensating parts of a pendulum can be 
safely made within one and a half pounds or lighter, and 
carry a bob of twenty-five pounds or over without buckling 
the rods, and the two points, the center of gravity and the 
center of oscillation, will be within the range of the screw. 
There are still some other forces to be considered as af- 
fecting the performance of our pendulum. These are the 
resistance to its momentum offered by the air and the resist- 
ance of the suspension spring. 

Barometric Error. — If we adjust a pendulum in a clock 
with an airtight case so that the pendulum swings a certain 
number of degrees of arc, as noted on the degree plate in 
the case at the foot of the pendulum, and then start to pump 
out the air from the case while the clock is running, we shall 
find the pendulum swinging over longer arcs as the air be- 
comes less until we reach as perfect a vacuuni as we can 
produce. If we note this point and slowly admit air to the 
case again we shall find that the arcs of the pendulum's 
swing will -he slowly shortened until the pressure in the 
case equals that of the surrounding air, when they will be 
the same as when our experiment was started. If we now 
pump air into our clock case, the vibrations will become 
still shorter as the pressure of the air increases, proving con- 
clusively that the resistance of the air has an effect on the 
swinging of the pendulum. 

We are accustomed to measure the pressure of the air as 
it changes in varying weather by 'means of the barometer 
and hence we call the changes in the swing of the pendulum 
due to varying air pressure the ^'barometric error." The 
barometric error of pendulums is only considered in the 



THE MODERN CLOCK. 21 

very finest of clocks for astronomical observatories, master 
clocks for watch factories, etc., hut the resistance of the air 
is closely considered v^hen we come to shape our bob. This 
is why bobs are either double-convex or cylindrical in shape, 
as these two forms offer the least resistance to the air and 
(which is more important) they offer equal resistance on 
both sides of the center of the bob and thus tend to keep 
the pendulum, swinging in a straight line back and forth. 

The Circular Error. — As the pendulum swings over a 
greater arc it will occupy more time in doing it and thus 
the rate of the clock will be affected, if the barometric 
changes are very great. This is called the circular error. 
In ancient times, when it was customary to make pendulums 
vibrate at least fifteen degrees, this error was of importance 



Fig. 4. A, arc of circle. B, cycloid path of pendulum, exaggerated. 

and clock makers tried to make the bob take a cycloidal 
path, as is shown in Fig. 4, greatly exaggerated. This was 
accomplished by suspending the pendulum by a cord which 
swung between cycloidal cheeks, but it created so much fric- 
tion that it was abandoned in favor of the spring as used 
to-day. It has since been proved that the long and short 
arcs of the pendulum's vibration are practically isochronous 
(with a spring of proper length and thickness) up to about 
six degrees of arc (three degrees each side of zero on the 
degree plate at the foot of the pendulum) and hence small 
variations of power in spring-operated clocks and also the 
barometric error are taken care of, except for greatly in- 
creased variations of power, or for too great arcs of vibra- 
tion. Here we see the reasons for and the amount of swing 
v»re can properly give to our pendulum. 



22 THE MODERN CLOCK. 

Temperature Error. — The temperature error is the 
greatest which we shall have to consider. It is this which 
makes the compound pendulum necessary for accurate time, 
and we shall consequently give it a great amount of space, 
as the methods of overcoming it should be fully understood. 

Expansion of Metals. — The materials commonly used 
in m.aking pendulums are wood (deal, pine and mahogany), 
steel, cast iron, zinc, brass and mercury. Wood expands 
.0004 of its length between 32°. and 212° F. ; lead, .0028; 
steel, .0011; mercury, .0180; zinc, .0028; cast iron, .oori ; 
brass, .0020. Now the length of a seconds pendulum, by 
our tables (3600 beats per hour) is 0.9939 meter; if the rod 
is brass it will lengthen .002 with such a range of tempera- 
ture. As this is practically two-thousandths of a meter, this 
is a gain of two millimeters, which would produce a varia- 
tion of one minute and forty seconds every twenty-fouf 
hours; consequently a brass rod would be a very bad one. 

If we take two of these materials, with as wide a differ- 
ence in expansion ratios as possible, and use the least 
variable for the rod and the other for the bob, supporting it 
at the bottom, we can make the expansion of the rod coun- 
terbalance the expansion of the bob and thus keep the effec- 
tive length of our pendulum constant, or nearly so. This is 
the theory of the compensating pendulum. 



CHAPTER III. 

COMPENSATING PENDULUMS. 

As the pendulum is the means of regulating the time con- 
sumed in unwinding the spring or weight cord by means 
of the escapement, passing one tooth of the escape wheel 
at each end of its swing, it will readily be seen that length- 
ening or shortening the pendulum constitutes the means of 
regulating the clock; this would make the whole subject a 
very simple affair, were it not that the reverse proposition 
is also true ; viz. ; Changing the length of the pendulum 
will change the rate of the clock and after a proper rate has 
been obtained further changes are extremely undesirable. 
This is what makes the temperature error spoken of in the 
preceding chapter so vexatious where close timing is de- 
sired and why as a rule, a well compensated pendulum costs 
more than the rest of the clock. The sole reason for the 
business existence "of watch and clockmakers lies in the 
necessity of measuring time, and the accuracy with which 
it may be done decides in large measure the value of any 
watchmaker in his community. Hence it is of the utmost 
importance that he shall provide himself with an accurate 
means of measuring time, as all his work must be judged 
finally by it, not only while he is working upon time-meas- 
uring devices, but also after they have passed into the pos- 
session of the general public. 

A good clock is one of the very necessary foundation 
elements, contributing very largely to equip the skilled me- 
chanic and verify his work. Without some reliable means 
to get accurate mean time a watchmaker is always at sea — 
without a compass — and has to trust to his faith and a 

23 



24 THE MODERN CLOCK. 

large amount of guessing, and this is always an embarrass- 
ment, no matter how skilled he may be in his craft, or adept 
in guessing. What I want to call particular attention to is 
the unreliable and worthless character of the average regu- 
lator of the present day. A good clock is not necessarily a 
high' priced instrument and it is within the reach of most 
watchmakers. A thoroughly good and reliable timekeeper 
of American make is to be had now in the market for less 
than one hundred dollars, and the only serious charge that 
can be made against these clocks is that they cost the con- 
sumer too much money. Any of them are thirty-three and 
a third per cent higher than they should be. About seventy- 
five dollars will furnish a thoroughly good clock. The aver- 
age clock to be met with in the watchmakers' shops is the 
Swiss imitation • gridiron pendulum, pin escapement, and 
these are of the low grades as a rule; the best grades of 
them rarely ever get into the American market. Almost 
without exception, the Swiss regulator, as described, is 
wholly worthless as a standard, as the pendulums are only 
an imitation of the real compensated pendulum. Tkey are 
an imitation all through, the bob being hollow and filled 
with scrap iron, and the brass and steel rods composing the 
compensating element, along with the cross pieces or bind- 
ers, are all of the cheapest and poorest description. If one 
of these pendulums was taken away from the movement 
and a plain iron bob and wooden rod put to the movement, 
in its place, the possessor of any such clock would be sur- 
prised to find how m*uch better average rate the clock would 
have the year through, although there would then be no 
compensating mechanisrh, or its semblance, in the make up 
of the pendulum. In brief, the average imitation compen- 
sation pendulum of this particular variety is far poorer 
than the simplest plain pendulum, such as the old style, 
grandfather clocks were equipped with. A wood rod would 
be far superior to a steel one, or any metal rod, as may be 
seen bv consulting the expansion data given in the previous 
chapter 



THE MODERN CLOCK. 



^5 



Many other pendulums that are sold as compensating 
are a delusion in part, as they do not thoroughly compen- 
sate, because the elements composing them are not in 
equilibrium or in due proportion to one another and to the 
general mechanism. 

To all workmen who have a Swiss regulator, I would 
say that the movement, if put into good condition, will an- 
swer very well to niaintain the motion of a good pendulum, 
and that it will pay to overhaul these movements and put 
to them good pendulums that will pretty nearly compen- 
sate. At least a well constructed pendulum will give a 
very useful and reliable rate with such a motor, and be a 
great help and satisfaction to any man repairing and rating 
good watches. 

The facts are, that one of the good grade of American 
adjusted watch movements will keep a much steadier rate 
when maintained in one position than the average regulator. 
Without a reliable standard to regulate by, there is very 
little satisfaction in handling a good movement and then not 
be able to ascertain its capabilities as to rate. Very many 
watch carriers are better up in the capabilities of good 
watches than many of our American repairers are, because 
a large per cent of such persons have bought a watch of 
high grade with a published rate, and naturally when it is 
made to appear to entirely lack a constant rate when com- 
pared with the average regulator, they draw the conclusion 
that the clock is at fault, or that the cleaning and repairing 
are. Many a fair workman has lost his watch trade, largely 
on account of a lack of any kind of reliable standard of 
time in his establishment. There, are very few things that 
a repairer can do in the way of advertising and holding his 
customers more than to keep a good clock, and furnish 
good watch owners a means of comparison and thus to con- 
firm their good opinions of their watches. 

We have along our railroads throughout the country a 
standard time system of synchronized clocks, which are an 



26 THE MODERN CLOCK. 

improvement over no standard of comparison; but they 
cannot be depended upon as a reliable standard, because 
they are subject to all the uncertainties that affect the tele- 
graph lines^ — bad service, lack of skill, storms, etc. The 
clocks furnished by these systems are not reliable in them- 
selves and they are therefore corrected once in twenty-four 
hours by telegraph, being automatically set to mean time by 
the mechanism for that purpose, which is operated by a 
standard or master clock at some designated point in the 
system. 

Now all this is good in a general way ; but as a means to 
regulate a fine watch and use as a standard from day to 
day, it is not adequate. A standard clock, to be thoroughly 
serviceable, must always, all through the twenty-four hours, 
have its seconds hand at the correct point at each minute 
and hour, or it is unreliable as a standard. The reason is 
that owing to train defects watches may vary back and 
forth and these errors cannot be detected with a standard 
that is right but once a day. No man can compare to a 
certainty unless his standard is without variation, substan- 
tially ; and I do not know of any way that this can be ob- 
tained so well and satisfactorily as through the means of 
a thoroughly good pendulum. 

Compensating seconds pendulums are, it might be said, 
the standard time measure. Mechanically such a pendulum 
is not in any way difficult of execution, yet by far the 
greater portion of pendulums beating seconds are not at all 
accurate time measures, as independently of their slight 
variations in length, any defects in the construction or fit- 
ting of their parts are bound to have a direct effect upon 
the performance of the clock. The average watchmaker 
as a mechanic has the ability to do the work properly, but 
he does not fully understand or realize what is necessary, 
nor appreciate the fact that little things not attended to 
will render useless all his efforts. 

The first consideration in a compensated pendulum is to 



THE MODERN CLOCK. 27 

maintain the center of oscillation at a fixed distance from 
the point of suspension and it does not matter how this is 
accomplished. 

So, also, the details of construction are of little conse- 
quence, so long as the main points are well looked after — 
the perfect solidity of all parts, with very few of them, and 
the free movement of all working surfaces without play, so 
that the compensating action may be constantly maintained 
at all times. Where this is not the case the sticking, rat- 
tling, binding or cramping of certain parts will give differ- 
ent rates at different times under the same variations of 
temperature, according as the parts work smoothly and 
evenly or move only by jerks. 

The necessary and useful parts of a pendulum are all that 
are really admissible in thoroughly good construction. Any 
and all pieces attached by way of ornament merely are apt 
to act to the prejudice of the necessary parts and should 
be avoided. In this chapter we shall give measurements 
and details of construction for a number of compensated 
pendulums of various kinds, as that will be the best means 
of arriving at a thorough understanding of the subject, 
even if the reader does not desire to construct such a pen- 
dulum for his own use. 

Principles of Construction. — Compensation pendu- 
lums are constructed upon two distinct principles. First, 
those in which the bob is supported by the bottom, resting 
on the adjusting screw with its entire height free to expand 
upward as the rod expands downward from its fixed point 
of suspension. In this class of pendulums the error of the 
bob is used to counteract that of the rod and if the bob is 
made of sufficiently expansible metal it only remains to 
make the bob of sufficient height in proportion to its ex- 
pansibility for one error to offset the other. In the second 
class the attempt is made to leave out of consideration any 
errors caused by expansion of the bob, by suspending it 



28 THE MODERN GLQCK. 

from the center, so that its expansion downward will ex- 
actly balance its expansion upward, and hence they will bal- 
ance each other and may be neglected. Having, eliminated 
the bob from consideration by this m^ans we must neces- 
sarily confine our attempt at compensation to the rod in the 
second method. 

The wood rod and lead bob and the mercurial pendulums 
are examples of the first-class and the wood rod with brass 
sleeve having a nut at the bottom and reaching to the center 
of the iron bob and the common gridiron, or compound 
tubular rod, or compound bar of steel and brass, or -steel 
and zinc, are examples of the second class. 

Wood Rod and Zinc Bob. — We will suppose that we 
have one of the Swiss imitation gridiron pendulums which 
we want to discard, while retaining the case and movement. 
As these cases are wide and generally fitted with twelve- 
inch dials, we shall have about twenty inches inside our case 
and we may therefore use a large bob, lens-shaped,, made of 
cast zinc, polished and lacquered to look like brass. 

The bobs in such imitation gridiron pendulums are gener- 
ally about thirteen inches in diameter and swing about five 
inches (two and a half inches each side). The. pendulums 
are generally light, convex in front and flattened at the 
rear, and the entire pendulum measures about 56 inches 
from the point of suspension to the lower end of the adjust- 
ing screw. We will also suppose that we desire to change 
the appearance of the clock as little as possible, while im- 
proving its rate. This will mean that we desire to retain a 
lens-shaped bob of about the same size as the one we are 
going to remove. 

We shall first need to know the total length of our pen- 
dulum, so that we can calculate the expansion of the rod. 
A seconds pendulum measures 39.2 inches from the point 
in the suspension spring at the lower edge of the chops to 
the center of oscillation. With a lens-shaped bob the center 



THE MODERN CLOCK. * '29 

of gravity will be practically at the center of the bob, if we 
use a light \vooden rod arid a steel adjusting screw and 
brass nut, as these metal parts, although short, will be 
heavy enough to nearly balance the suspension spring and 
that portion of the rod which is above the center. We shall 
also gain a little in balance if we leave the steel screw. long 
enough to act as an index over the degree .plate, in the case, 
at the bottom of the pendulum, by stripping the thread and 
turning the end to a taper an inch or so in length. 

We shall only be able to use one-half of the expansion 
upwards of our bob, because the centers of gravity and os- 
cillation will be practically together at the center of the bob. 
We shall find the center of gravity easily by balancing the 
pendulum on a knife-edge and thus we will be able to make 
an exceedingly close guess at the center of oscillation. 

Now, looking over our data, we find that we have a sus- 
pension spring of steel, then some wood and steel again at 
the other end. We shall need about one inch of suspension 
spring. The spring will, of course, be longer than one 
inch, but we shall hold it in iron chops and the expansion 
of the chops will equal that of the spring between them, so 
that only the free part of the spring need be considered. 
Now from the adjusting screw, where it leaves the last 
pin through the wood, to the middle position of the rating 
nut will be about one inch, so we shall have two inches of 
steel to consider in our figures of expansion. 

Now to get the length of the rod. We want to keep our 
bob about the size of the other, so we will try 14 inches 
diameter, as half of this is an even number and makes easy 
figuring in our trials. 39.2 inches, plus 7 (half the diameter 
of the bob) gives us 46.2 inches; now we have an inch of 
adjustment in our screw, so we can discard the .2; this 
leaves us 46 inches of wood and steel for which we must 
get the expansion. 



JO ♦ THE MODERN CLOCK. 

Wood expands .0004 of its length between 32° and 212° F. 
Steel expands .0011 of its length between 32° and 212° F. 
Lead expands .0028 of its length between 32° and 212° F. 
Brass expands .0020 of its length between 32** and 212" F. 
Zinc expands .0028 of its length between 32** and 212° F. 
Tin expands .0021 of its length between 32** and 212° F. 
Antimony expands .0011 of its length between 32° and 212° F. 
Total length of pendulum to adjusting nut 46 inches. 
Total length of steel to adjusting nut 2 inches. 
Total length of wood to adjusting nut 44 inches. 
,0011 X 2 = .0022 inch, expansion of our steel. 
.0004 X 44:= .0176 inch, expansion of our wood. 



.0198 total expansion of rod. 

We have 7 inches as half the diameter of our bob 
.0198 -^ 7 = .0028 2-y, which we find from our tables is 
very close to the expansion of zinc, so we will make the bob 
of that metal." Now let us check back ; the upward expan- 
sion of 7 inches of zinc equals .0028 X .7 ^ .0196 inch, as 
against .0198 inch downward expansion of the rod. This 
gives us a total difference of .0002 inch between 32° and 
212° or a range of 180° F. This is a difference of .0001 
inch for 90° of temperature and is closer than most pendu- 
lums ever get. 

The above figures are for dry, clear white pine, well 
baked and shellacked, with steel of average expansion, and 
zinc of new metal, melted and cast without the admixtures 
of other metals or the formation of oxide. The presence 
of tin, lead, antimony and other admixtures in the zinc 
would of course change the results secured; so also will 
there be a slight difference in the expansion of the rod if 
other woods are used. Still the jeweler can from the above 
get a very close approximation. 

Such a bob, 14 inches diameter and 1.5 inches thick, alike 
on both sides, with an oval hole ix.5 inches through its cen- 
ter, see Fig. 5, would weigh about 30 to 32 pounds, and 



THE MODERN CLOCK. 



31 



f 



o , o 

Tor 

I 





Fig. 5. Zinc bob and wood rod to replace imitation gridiron pendulum. 



32 



THE MODERN CLOCK. 



would have to be hung from a cast iron bracket, Fig. 6, 
bolted through the clock case to the wall behind it, so as to 
get a steady rate. It would be nearly constant, as the metal 
is spread out so as to be quickly affected by temperature; 
and the shape would hold it well in its plane of oscillation, 
if both sides were of exactly the same curvature, while the 




n 



Fig. G. Cast iron bracket for lieavy pendulums and movements. 

weight would overcome minor disturbances due to vibration 
of the building. It would require a little heavier suspension 
spring, in order to be isochronous in the long and short 
arcs and this thickening of the spring would need the addi- 
tion of from one and a half to two pounds rnore of driving 
weight. 

If so heavy a pendulum is deemed undesirable, the bob 
would have to be made of cylindrical form, retaining the 
height, as necessary to compensation, and varying the diam- 
eter of the cylinder to suit the weight desired. 



Wood Rod and Lead Bob. — The wood should be clear, 
straight-grained and thoroughly dried, then given several 
coats of shellac varnish, well baked on. It may be either 



THE MODERN CLOCK. 



33 





Fig. 7. "Wood rod and 
lead bob. 



Fig. 8. Bob of metal casing 
filled with shot. 



34 THE MODERN CLOCK. 

flat, oval or round in section, but is generally made round 
because the brass cap at the upper end, the lining for the 
crutch, and the ferrule for the adjusting screw at the lower 
end may then be readily made from tubing. For pendu- 
lums smaller than one second, the wood is generally hard, 
as It gives a firmer attachment of the metal parts. 

Inches. 

Length, top of suspension spring to bottom of bob 44.S 

Length to bottom of nut 45.25 

Diameter of bob 2.0 

Length of bob 10.5 

V/eight of bob, 3 lbs. 

Acting length of suspension spring i.o 

Width of spring 45 

Thickness .008 

Diameterr of rod 5 

The top of the rod should have a brass collar fixed on it 
by riveting through the rod and it should extend down the 
rod about three inches, so as to make a firm support for the 
slit to receive the lower clip of the suspension spring. The 
lower end should have a slit or a round hole drilled longi- 
tudinally three inches up the rod to receive the upper end of 
the adjusting screw and this should also fit snugly and be 
well pinned or riveted in place. See Fig. 7. A piece of 
thin brass tube about one inch in length is fitted over the 
rod where the crutch works. 

In casting zinc and lead bobs, especially those of lens- 
shapes, the jeweler should not attempt to do the work him- 
self, but should go to a pattern maker, explain carefully 
just what is wanted and have a pattern made, as such pat- 
terns must be larger than the casting in order to take care 
of the shrinkage due to cooling the molten metal. It will 
also be better to use an iron core, well coated with graphite 
when casting, as the core can be made smooth throughout 
and the exact shape of the pendulum rod, and there will 
then be no work to be done on the hole when the casting 
is made. The natural shrinkage of the metal on cooling 



THE MODERN CLOCK. 3^ 

will free the core, which can be easily driven out when 
the metal is cc5ld and it will then leave a smooth, well 
shaped hole to which the rod can be fitted to work easily, 
but without shake. Lens-shaped bobs, particularly, should 
be cast flat, with register pins on the flask, so as to get both 
sides central with the hole, and be cast with a deep riser 
large enough to put considerable pressure of melted metal 
on the casting until it is chilled, so as to get a sound cast- 
ing ; it should be allowed to remain in the sand until thor- 
oughly cold, for the same reason, as if cooled quickly the 
bob will have internal stresses which are liable to adjust 
themselves sometime after the pendulum is in the clock 
and thus upset the rate until such interior disturbances have 
ceased. Cylinders may be cast in a length of steel tubing, 
using a round steel core and driven out when cold. 

If using oval or flat rods of wood, the adjusting screw 
should be flattened for about three inches at its upper end, 
wide enough to conform to the width of the rod ; then saw 
a slot in the center of the rod, wide and deep enough to just 
fit the flattened part of the screw ; heat the screw and apply 
shellac or lathe wax and press it firmly into the slot with 
the center of the screw in line with the center of the rod; 
after the wax is cold select a drill of the same size as the 
rivet wire; drill and rivet snugly through the rod, smooth 
everything carefully and the job is complete. 

If by accident you have got the rod too small for the hole, 
so that there is any play, give the- rod another coat of 
shellac varnish and after drying thoroughly, sand paper it 
down until it will fit properly. 

Round rods may be treated in the same manner, but it is 
usual to drill a round hole in such a rod to just fit the 
wire, then insert and rivet as before after the wax is cold, 
finishing with a ferrule or cap of brass at the end of the 
rod. 

The slot for the suspension spring is fitted to the upper 
end of the rod in the same manner. 



36 THE MODERN CLOCK. 

Pendulum with Shot. — Still another method of mak- 
ing a compensating pendulum, which gives a lighter pendu- 
lum, is to make a case of light brass or steel tubing of about 
three inches diameter. Fig. 8, with a bottom and top of 
equal weight, so as to keep the center of oscillation about 
the center of gravity, for convenience in working. The bot- 
tom may be turned to a close fit, and soldered, pinned, or 
riveted into the tube. It is pierced at its center and another 
tube of the same material as the outer tube, with an internal 
diameter which closely fits the pendulum rod is soldered or 
riveted into the center of the bottom, both bottom and top 
being pierced for its admission and the other parts fitted as 
previously described. 

The length of the case or canister should be about 11.5 
inches so as to give room for a column of shot of 10.5 
inches (the normal compensating height for lead) and still 
leave room for correction. Make a tubular case for the 
driving weight also and then we have a flexible system. 
If it is necessary to add or subtract weight to obtain the 
proper arcs of oscillation of the pendulum, it can be readily 
done by adding to or taking from the shot in the weight 
case. 

Fill the pendulum to 10.5 inches with ordinary sports- 
men's shot and try it for rate. If it gains in heat and loses 
in cold it is over-compensated and shot must be taken from 
it. If it loses in heat and gains in cold it is under-com- 
pensated and shot should be added. 

The methods of calculation were given in full in describ- 
ing the zinc pendulum and hence need not be repeated here,, 
but attention should be called to ' the ' fact that there are 
three materials here, wood, steel or brass and lead and each 
should be figured separately so that the last two may just 
counterbalance the first. If the case is made light through- 
out the effect upon the center of oscillation will be inappre- 
ciable as compared with that of the lead, but if made 
heavier than need be, it will exert a marked influence, par« 



THE MODERN CLOCK. 



37 



ticularly if its highest portion (the cover) be heavy, as we 
then have the effect of a shifting weight high up on the 
pendulum rod. If made of thin steel throughout and nickel 
plated, we shall have a light and handsome case for our 
bob. If this is not practicable, or if the color of brass be 
preferred, it may be made of that material. 

The following table of weights will be of use in making 
calculations for a pendulum or for clock weights. 

"Weight of Lead, Zinc and Cast Iron Cylinders One Half Inch Long. 



Diameter 


Weight in Pounds 


Diameter 
in Inches 


Weight in Pounds 


in Inches. 


Lead 


Zinc 


Iron 


Lead 


Zinc 


Iron 


.25 


.020 


.012 


.012 


3 25 


3 400 


2.098 


2.156 


.5 


.080 


.049 


.050 


3 5 


3.944 


2.434 


2.491 


.75 


.180 


.111 


.114 


3 75 


4 51 


2.783 


2 865 


1 


.321 


.198 


.204 


4 


5149 


3.177 


3.265 


1.25 


.503 


.310 


.319 


4 25 


5 813 


3.587 


3 686 


1.5 


.724 


.447 


.459 


4.5 


6 619 


3 922 


4.134 


1.75 


.984 


.607 


.624 


4.75 


7 265 


4 483 


4.607 


2. 


1.287 


.794 


.816 


5 


8 048 


4966 


5.103 


2 25 


1630 


1.005 


1033 


5.25 


8 872 


5.474 


5.626 


2.5 


2.009 


2 239 


1274 


5 5 


9 737 


6.008 


5.175 


2.75 


2.434 


1502 


1544 


5.75 


10.643 


6.567 


6.749 


3. 


2.897 


1788 


1837 


6 


11.590 


7.152 


7.350 



Example:— Required, the weight of a lead pendulum bob, 3 
inches diameter, 9 inches long, which has a hole through it .75 inch 
in diameter. The weight of a lead cylinder 3 inches diameter i.a the 
table is 2 897, which multiplied by 9 (the length given)=26.07 lbs. 
Then the weight in the table of a cylinder .75 inch diameter is .18 
and .18X9 = 1.62 lbs. And 26.07 - 1.62=24.45. the weight required in 
lbs. 



Auxiliary Weights. — If for any reason our pendulum 
does not turn out with a rating as calculated and we find 
after getting it to time that it is over compensated, it is a 
comparatively simple matter to turn off a portion from the 
bottom of a solid bob. By doing this in very small por- 
tions at a time and then testing carefully for heat and cold 
every time any amount has been removed, we shall in the 



38 THE MODERN CLOCK. 

course of a few weeks arrive at a close approximation to 
compensation, at least as close as the ordinary standards 
available to the jeweler will permit. This is a matter of 
weeks, because if the pendulum is being rated by the stan- 
dard time which is telegraphed over the country daily at 
noon, the jeweler, as soon as he gets his pendulum nearly 
right, will begin to discover variations in the noon signal of 
from .2 to 5 seconds on successive days. Then it becorhes 
a matter of averages and reasoning, thus: If the pendu- 
lum beats to , time on the first, second, third, fifth and 
seventh days, it follows that the signal w^as incorrect — slow 
or fast— on the fourth and sixth days. 

If the pendulum shows a gain of one second a week on 
the majority of the days, the observation must be continued 
without changing the pendulum for another week. If the 
pendulum shows two seconds gain at the end of this 
time, we have tw^o things to consider. Is the length right, 
or is the pendulum not fully compensated? We cannot an- 
swer the second query without a record of the temperature 
variations during the period of observations. 

To get the temperature record we shall require a set of 
maximum and minimum thermometers in our clock case. 
They consist of mercurial thermometer tubes on the ordi- 
nary Fahrenheit scales, but with a marker of colored wood 
or metal resting on the upper end of the column of mercury 
in the tube. The tube is not hung vertically, but is placed 
in an inclined position so that the mark will stay where it 
is pushed by the column of mercury. Thus if the tem- 
perature rises during the day to 84 degrees the mark in the 
maximum thermometer will be found resting in the tube 
at 84° whether the mercury is there when the reading is 
taken or not. Similarly, if the temperature has dropped 
during the night to 40°, the mark in the minimum ther- 
mometer will be found at 40°, although the temperature 
may be 70° w^hen the reading is taken. After reading, the 
thermometers are shaken to bring the marks back to the top 



THE MODERN CLOCK. 



39 



of the column of mercury and the thermometers are then 
restored to their positions, ready for another reading on the 
following day. 

These records should be set down on a sheet every day 
at noon in columns giving date, rate, plus or minus, maxi- 
mum, minimum, average temperature and remarks as to 
regulation, etc., and with these data to guide us we shall be 
in a position to determine whether to move the rating nut or 
not. If the temperature has been fairly constant we can 
get a closer rate by moving the nut and continuing the ob- 
servations. If the temperature has been increasing steadily 
and our pendulum has been gaining steadily it is probably 
over-compensated and the bob should be shortened a trifle 
and the observations renewed. 

It is best to ''make haste slowly" in such a matter. First 
bring the pendulum to time in a constant temperature ; that 
will take care of its proper length. Then allow the tem- 
perature to vary naturally and note the results. 

If the pendulum is under-compensated, so that the bob is 
too short to take care of the expansion of the rod, auxiliary 
weights of zinc in the shape of washers (or short cylinders) 
are placed between the bottom of the bob and the rating 
nut. This of course makes necessary a new adjustment and 
another course of observations all around, but it will readily 
be seen that it places a length of expansible metal between 
the nut and the center of oscillation and thus makes up for 
the deficiency of expansion of the bob. Zinc is generally 
chosen on account of its high rate of expansion, but brass, 
aluminum and other metals are also used. It is best to use 
one thick washer, rather than a number of thinner ones, as 
it is important to keep the construction as solid at this point 
as possible. 

Top Weights. — After bringing the pendulum as close 
as possible by the compensation and the rating nuts, astron- 
omers and others requiring exact time get a trifle closer rat- 



40 THE MODERN CLOCK. 

ing by the use of top weights. These are generally U- 
shaped pieces of thin metal which are slipped on the rod 
above the bob without stopping the pendulum. They raise 
the center of oscillation by adding to the height of the bob 
when they are put on, or lower it when they are removed, 
but they are never resorted to until long after the pendulum 
is closer to time than the jeweler can get with his limited 
standards of comparison. They are mentioned here simply 
that their use may be understood when they may be encoun- 
tered in cleaning siderial clocks. 

Mercurial pendulums also belong to the class of com- 
pensation by expansion of the bobs, but they are so numer- 
ous and so different that they will be considered separately, 
later on. 

Compensated Pendulum Rods. — We will now consider 
the second class, that in which an attempt is made to obtain 
a pendulum rod of unvarying length. 

The oldest form of compensated rod is undoubtedly the 
gridiron of either nine, five or three rods. As originally 
made it was an accurate but expensive proposition, as the 
coefficients of expansion of the brass or zinc and iron or 
steel had all to be determined individually for each pendu- 
lum. Each rod had to be sized accurately, or if this was 
not done, then each rod had to be fitted carefully to each 
hole in the cross bars so as to move freely, without shake. 
The rods were spread out for two purposes, to impress 
the public and to secure uniform and speedy action in 
changes of temperature. The weight, which increased 
rapidly with the increase of diameter of the rod, made a 
long and large seconds pendulum, some of them measuring 
as much as sixty-two inches in length, and needing a large 
bob to look in proportion. Various attempts w^ere made 
to ornament the great expanse of the gridiron, harps, 
wreaths and other forms in pierced metal being screwed 
to the bars. The next advance was in substituting tubes for 



THE MODERN CLOCK. 4I 

rods in the gridiron, securing an apparently large rod that 
was at the same time stiff and light. Then came the era of 
imitation, in which the rods were made of all brass, the 
imitation steel portion being nickel plated. With the devel- 
opment of plating they were still further cheapened by 
being made of steel, with the supposedly brass rods plated 
with brass and the steel ones with nickel. Thousands of 
such pendulums are in use to-day ; they have the rods riv- 
eted to the cross-pieces and are simply steel rods, subject to 
change of length with every change in temperature. It 
does no harm to ornament such pendulums, as the rods 
themselves are merely ornaments, usually all of one metal, 
plated to change the color. 

As three rods were all that were necessary, the clock- 
maker who desired a pendulum that was compensated soon 
found his most easily made rod consisted of a zinc bar, 
wide, thin and flat, placed between two steel parts, like the 
meat and bread of a sandwich. This gives a flat and appar- 
ently solid rod of metal which if polished gives a pleasing 
appearance, and combines accurate performance with cheap- 
ness of construction, so that any watchmaker may make it 
himself, without expensive tools. 

Flat Compensated Rod. — One of the most easily made 
zinc and iron compensating pendulums, shown in detail in 
Fig. 9, is as follows : A lead or iron bob, lens shaped, that 
is, convex equally on each side, 9 inches diameter and an 
inch and one-quarter thick at the center. A hole to be 
made straight through its diameter ^ inch. One-half 
through the diameter this hole is to be enlarged to ^4, inch 
diameter. This will make the hole for half of its length 
]/2 inch and the remaining half ^ inch diameter. The 
% hole must have a thin tube, just fitting it, and 5 inches 
long. At one end of this tube is soldered in a nut, with a 
hole tapped with a tap of thirty-six threads to the inch, and 
}i inch diameter, and at the other end of the tube is 



42 



THE MODERN CLOCK. 




A, the lens-shaped bob; T P, the 
total length of the compensating 
part. 

R, the upper round part of rod. 

The side showing the heads of 
the screws is the face side and is 
finished. The screws 1,2,3,4 hold 
the three pieces from separating, 
but do not confine the front and 
middle sections in their lengthwise 
expansion along the rod, but are 
screwed into the back iron section, 
while the holes in the other two 
sections are slotted smaller than 
the screw heads. 

The holes at the lower extreme 
of combination 5, 6, 7, 8, 9 are for 
adjustments in effecting a com- 
pensation. 

The pin at 10 is the steel adjusting 
pin, and is only tight in the front 
bar and zinc bars, being loose in 
the back bar. 

and P show the angles in the 
back rod, T shows the angle in the 
rod at the top, m shows the pin as 
placed in the iron and zinc sections 
wherfe they have been soldered as 
described. 

h shows the regulating nut car- 
ried by the tube, as described, and 
terminating in the nut D. 

1 and i show the screw of 36 threads. 
The nut D is to be divided on its 

edge into 30 divisions. 

n is the angle of the back bar to 
which zinc is soldered. 



Fig. 9. Pendulum with compensated rod of steel and zinc. 



THE MODERN CLOCK. 43 

soldered a collar or disc one inch diameter, which is to be 
divided into thirty divisions, for regulating purposes, as will 
be described later on. The whole forms a nut into which 
the rod screws, and the tube allows the nut to be pushed 
up to the center of the diameter of the bob, through the 
large hole, and the nut can be operated then by means of 
the disc at its lower end. The rod, of flat iron, is in two sec- 
tions, as follows : That section which enters the bob and 
terminates in the regulating screw is flat for twenty-six 
inches, and then rounded to Yz inch for six inches, and a 
screw cut on its end for two inches, to fit the thread in the 
nut. The upper end of this section is then to be bent 
at a right angle, flatwise. This angle piece will be long 
enough if only 3-16 inch long, so that it covers the thick- 
ness of the zinc center rod. The zinc center rod is a bar of 
the. metal, hammered or rolled, 25 inches long, 3-16 inch 
thick, and ^ inch wide, and comes up against the angle 
piece bent on the flat part of the lower section of the rod. 
Now the upper section of the rod may be an exact duplicate 
of the lower section, with the flat part only a little longer 
than the zinc bar, say Yz inch, and the angle turned on the 
end, as j)reviously described. The balance of the bar may 
be forged into a rod of 5-16 inch diameter. As has been 
stated, "the zinc bar is placed against the angle piece bent 
on the upper end of the lower section of the rod, P, n. Fig. 
9, and pins must be put through this angle piece into the 
end of the zinc bar, to hold it in close contact with the iron 
bar. The upper section of the rod is now to be laid on the 
opposite side of the zinc bar, with its angle at the other end 
of the zinc, but not in contact with it, say 1-16 inch left 
between the angle and the zinc bar. Now all is ready to 
clamp together — the two flat iron bars with the zinc between 
them. After clamping, taking care to have the pinned end 
of the zinc in contact with the angle and the free, or lower 
end, removed from the other angle about 1-16 inch, three 
screws should be put through all three bars, with their 



44 THE MODERN CLOCK. 

heads all on the side selected for the front, and one screw 
may be an inch from the top, another 3 inches from the 
bottom, and one-half way between the two first mentioned. 
Now the rod is complete in its composite form, and there 
is left only the little detail to attend to. Two flat bars, with 
their ends angled in one case and rounded in the other into 
rods of given diameter, confining between them, as de- 
scribed, a flat bar of wrought zinc of stated length and of 
the same thickness and width as the iron bars, comprises 
the active or compensating elements of the pendulum's rod. 
The screws that are put through the three bars are each to 
pass through the front iron bar, without threads in the bar, 
and only the back iron bar is to have the holes tapped, 
fitting the screws. All the corresponding holes in the zinc 
are to be reamed a little larger than the diameter of the 
screws, and to be freed lengthwise of the bar, to allow of 
the bar's contracting and expanding without being con- 
fined in this action by the screws. At the lower or free end 
of the zinc bar are to be holes carried clear through all three 
bars, while the combination is held firmly together by the 
screws. These holes are to start at ^ inch from the end 
of the zinc, and each carried straight through all three bars, 
and then broached true and a steel pin made to accurately 
fit them from the front side. These holes may be from 
three to five in number, extending up to a safe distance from 
the lower screw. The holes in the back bar, after boring, 
are to be reamed larger than those in the front bar and zinc 
bar. These holes and the pin serve for adjusting the com- 
pensation. The pin holds the front bar and zinc from slip- 
ping, or moving past one another at the point pinned, and 
also allows the back bar to be free of the pin, and not under 
the inflyence of the two front bars. The upper end of the 
second iron section is, as has been mentioned, forged into 
a round rod about 5-16 inch diameter, and this rod or 
upper end is to receive the pendulum suspension spring, 
which may be one single spring, or a compound spring, 
as preferred. 



THE MODERN CLOCK. 45 

Now that the pendulum is all ready to balance on the 
knife edge, proceed as in case of the simple pendulum, 
and ascertain at what point up the rod the spring must be 
placed. In this pendulum the rod will be heavier in propor- 
tion than the wood rod was to its bob, and the center of 
gravity of the whole will be found higher up in the bob. 
However, wherever in the bob the center of gravity is 
found, that is the starting point to measure from to find the 
total length of the rod, and the point for the spring. The 
heavier the rod is in relation to the bob, the higher will the 
center of gravity of the whole rise in the bob, and the 
greater will be the total length of the entire pendulum. 

In getting up a rod of the kind just described, the main 
item is to get the parts all so arranged that there will be 
very little settling of the joints in contact, particularly those 
which sustain the weight of the bob and the whole dead 
weight of the pendulum. The nut in the center of the 
pendulum holds the weight of the bob only, but it should 
fit against the shoulder formed for the purpose by the 
juncture of the two holes, and the face of the nut should be 
turned true and flat, so that there may not be any uneven 
motion, and only the one imparted by the progressive one 
of the threads. When this nut is put to its place for the 
last time, and after all is finished, there should be a little 
tallow put on to the face of the nut just where it comes 
to a seat against the shoulder of the bob, as this shoulder 
being not very well finished, the two surfaces coming in 
contact, if left dry, might cut and tear each other, and help 
to make the nut's action slightly unsteady and unreliable. 
A finished washer can be driven into this lower hole up to 
the center, friction tight, and serve as a reliable and finished 
seat for the nut. 

In reality, the zinc at the point of contact, where pinned to 
the angle piece at the top of the lower section, is the point 
of greatest importance in the whole combination, and if the 
joint between the angle and the end of the zinc bar is 



46 THE MODERN CLOCK. 

soldered with soft solder, the result will be that of greater 
certainty in the maintenance of a steady rate. This joint 
just mentioned can be soldered as follows: File the end 
of the zinc and the inside surface of the angle until they fit 
so that no appreciable space is left between them. Then, 
with a soldering iron, tin the end of the zinc thoroughly 
and evenly, and then put into the holes already made the 
two steady pins. Now tin in the same manner the surface 
of the angle, and see that the holes are free of solder, so that 
the zinc bar will go to its place easily ; then between the 
zinc and the iron, place a piece of thin writing paper, so 
that the flat surfaces of the zinc and iron may not become 
soldered. Set the iron bar upright on a piece of charcoal, 
and secure it in this position from any danger of falling, 
and then put the zinc to its place and see that the pins enter 
and that the paper is between the surfaces, as described. 
Put the screws into their places, and screw down on the 
zinc just enough to hold it in contact with the iron bar, but 
not so tight that the zinc will not readily move down and 
rest firmly on the angle. Put a little soldering fluid on the 
tinned joint, and blow with a blow pipe against the iron- 
bar (not touching the zinc with the flame). When the 
solder in the joint begins to flow, press the zinc down in 
close contact with the angle, and then cool gradually, and if 
all the points described have been attended to the joint will 
be solidly soldered, and the two bars will be as one solid 
bar bent against itself. The tinning leaves surplus solder on 
the surfaces suflicient to make a solid joint, and to allow 
some to flow into the pin holes and also solder the pin to 
avoid any danger of getting loose in after time, and helps 
make a much stronger joint. At the time the solder is 
melted the zinc is sufliciently heated to become quite mal- 
leable, and care must be taken not to force it down against 
the angle in making the joint, or it may be distorted and 
ruined at the joint. If carefully done the result will be 
perfect. The paper between the surfaces burns, and is got 



THE MODERN CLOCK. 47 

rid of in washing to remove the soldering fluid. Soda or 
ammonia will help to remove all traces of the fluid. How- 
ever, it is best, as a last operation, to put the joint in alcohol 
for a minute. 

This soldering makes the lower section and the zinc 
practically one piece and without loose joint, and the next 
joint is that made by the pin pinning the outside bar and the 
zinc together. This is necessarily formed this way, as in 
this stage of the operation we do not know just what length 
the zinc bar will be to exactly compensate for the expansion 
and contraction of the balance of the pendulum. By the 
changing of the pin into the different holes, 5, 6, 7, 8, 9, 10, 
Fig. 9, the zinc is made relatively longer or shorter, and so 
a compensation is arrived at in time after the clock has been 
running. After it is definitely settled where the pin will 
remain to secure the compensation of the rod, then that 
hole can have a screw put in to match the three upper ones. 
This screw must be tapped into the front bar and the zinc, 
and be very free in the back bar to allow of its expansion. 
It is supposed that in this example given of a zinc and steel 
compensation seconds pendulum that there has been due 
allowance made in the lengths of the several bars to allow 
for adjustment to temperature by the movements of the pin 
along the course of the several holes described, but the zinc 
is a very uncertain element, and its ultimate action is largely 
influenced by its treatment after being cast. Differences of 
working cast zinc under the hammer or rolls produce wide 
differences practically, and therefore materially change the 
results in its combination with, iron in their relative ex- 
pansive action. Wrought zinc can be obtained of any of the 
brass plate factories, of any dirriensions required, and will 
be found to be satisfactory for the purpose in hand. 

The adjusting pin should be well fitted to the holes in the 
front iron bar, and also fit the corresponding ones in the 
zinc bar closely, and if the holes are reamed smooth and 
true with an English clock broach, then the pin will be 



48 THE MODERN CLOCK. 

slightly tapering and fit the iron hole perfectly solid. After 
one pair of these holes have been reamed, fit the pin and 
drive it in place perfectly firm, and then with the broach 
ream all the remaining holes to just the same diameter, 
and then the pin will move along from one set of holes to 
another with mechanically accurate results. Otherwise, if 
poorly fitted, the full effect would not be obtained from the 
compensating action in making changes in the pin from 
one set of holes to another. This pin, if made of cast steel, 
hardened and drawn to a blue, will on the whole be a very 
good device mechanically. 

Many means are used to effect the adjustments for com- 
pensation, of more or less value, but whatever the means 
used, it must be kept in mind that extra care must be taken 
to have the mechanical execution first class, as on this very 
much depends the steady rate of the pendulum in after 
time. 

Tubular Compensated Rods. — There are tubular pendu- 
lums in the market which have a screw sleeve at the top of 
the zinc element, and by this means the adjustments are 
effected, and this is thought to be a very accurate mechan- 
ism. The most common form of zinc and iron compensa- 
tion is where the zinc is a tube combined with one iron tube 
and a central rod, as shown in Figs. lo, ii, 12. The rod 
is the center piece, the zinc tube next, followed by the iron 
tube enveloping both. The relative lengths may be the 
same as those just given in the foregoing example with the 
compensating elements flat. The relative lengths of the 
several members will be virtually the same in both com- 
binations. 

Tubular Compensation with Aluminum. — The pen- 
dulum as seen by an observer appears to him as being a 
simple single rod pendulum. Figs. 10 and 12 are front 
and side views ; Fig. 1 1 is an enlarged view of its parts, the 



THE MODERN CLOCK, 



49 



upper being a sectional view. Its principal features are: 
The steel rod S, Fig. ii, 4 mm. in diameter, having at its 
upper end a hook for fastening to the suspension spring in 
the usual way ; the lower end has a pivot carrying the bush- 
ing, T, which solidly connects the steel rod, S, with the 
aluminum tube. A, the latter being 10 mm. in diameter and 
its sides 1.5 mm. in thickness of the wall. 

The upper end of the aluminum tube is very close to the 
pendulum hook and is also provided with a bushing, P, 
Fig. II. This bushing is permanently connected at the 
upper end of the aluminum tube with a steel tube, R, 16 mm. 
in diameter and i mm. in thickness. The outer steel tube 
is the only one that is visible and it supports the bob, the 
lower part being furnished with a fine thread on which 
the regulating nut, O, is movable, at the center of the bob. 

For securing a central alignment of the steel rod, S, at its 
lowest part, where it is pivoted, a bushing, M, Fig. 11, is 
screwed into the steel tube, R. The lower end of the steel 
tube, R, projects considerably below the lenticular bob 
(compare Figs. 10 and 12) ; and is also provided with a 
thread and regulating weight, G (Figs. 10 and 12), of 100 
grammes in weight, which is only used in the fine regula- 
tion of small variations from correct time. 

The steel tube is open at the bottom and the index at its 
lower end is fastened to a bridge. Furthermore all three 
of the bushings, P, T and M, have each three radial cuts, 
which will permit the surrounding air to act equally and at 
the same time on the steel rod, S, the aluminum tube. A, and 
the steel tube, R, and as the steel tube, R, is open at its 
lower end, and as there is also a certain amount of space be- 
tween the tubes, the steel rod, and the radial openings in 
the bushings, there will be a draught of air passing through 
them, which will allow the thin- walled tubes and thin steel 
rod to promptly and equally adapt themselves to the temper- 
ature of the air. 




Fig. 10. 



Fig. U. 



Fig. 12. 



THE MODERN CLOCK. 5I 

The lenticular pendulum bob has a diameter of 24 cm., 
and is made of red brass. The bob is supported at its cen- 
ter by the regulating nut, O, Figs. 10 and 12. That the 
bob may not turn on the cylindrical pendulum rod, the latter 
is provided with a longitudinal groove and working therein 
are the ends of two shoulder screws which are placed on 
the back of the bob above and below the regulating nut, O ; 
and thus properly controlling its movements. 

From the foregoing description the action of the compen- 
sation is readily explained. For the purpose of illustration 
of its action we will accept the fact that there has been a 
sudden rise in temperature. The steel rod, S, and the tube, 
R, will lengthen in a downward direction (including the 
suspension spring and the pendulum hook), conversely the 
aluminum tube. A, which is fastened to the steel rod at one 
end and the steel tube at the other, will lengthen in an 
upward direction and thus equalize the expansion of the 
tube, R, and rod, S. 

As the coefficients of expansion of steel and aluminum are 
approximately at the ratio of 1 12.0313 we find that with such 
a pendulum construction — accurate calculations presumed 
— we shall have a complete and exact coincidence in its 
compensation ; in other words, the center of oscillation of 
the pendulum will be under all conditions at the same dis- 
tance from the bending point of the suspension spring. 

This style of pendulum is made for astronomical clocks in 
Europe and is furnished in two qualities. In the best qual- 
ity, the tubes, steel rod, and the bob are all separately and 
carefully tested as to their expansion, and their coefficients 
of expansion fully determined in a laboratory ; the bush- 
ings, P and M, are jeweled, all parts being accurately and 
finely finished. In the second quality the pendulum is con- 
structed on a general calculation and finished in a more 
simple manner without impairing its ultimate efficiency. 

At the upper part of the steel tube, R, there is a funnel- 
shaped piece (omitted in the drawing) in which are placed 



52 THE MODERN CLOCK. 

small lead and aluminum balls for the final regulation of the 
pendulum without stopping it. 

The regulation of this pendulum is effected in three 
ways : 

I. The preliminary or coarse regulation by turning the 
regulating nut, O, and so raising or lowering the bob. 
2. The finer regulation by turning the lOO grammes 
weight, g, having the shape of a nut and turning on the 
threaded part of the tube, R. 3. The precision regulation 
is effected by placing small lead or aluminum balls in a 
small funnel-shaped receptacle attached to the upper part 
of the tube, R, or by removing them therefrom. 

It will readily be seen that this form of pendulum can be 
used with zinc or brass instead of aluminum, by altering the 
lengths of the inner rod and the compensating tube to suit 
the expansion of the metal it is decided to use ; also that 
alterations in length may be made by screwing the bushings 
in or out, provided that the tube be long enough in the 
first place. After securing the right position the bushings 
should have pins driven into them through the tube, in order 
'to prevent further shifting. 



CHAPTER IV. 

THE CONSTRUCTION OF MERCURIAL PENDULUMS. 

Owing to the difficulty of calculating the expansive ratios 
of metal which (particularly with brass and zinc) vary 
slightly with differences of manufacture, the manufacture 
of compensated pendulums from metal rods cannot be re- 
duced to cutting up so many pieces and assembling them 
from calculations made previously, so that each must be 
separately built and tested. While this is not a great draw- 
back to the jeweler who wants to make himself a pendu- 
lum, it becomes a serious difficulty to a manufacturer, and 
hence a cheaper combination had to be devised to prevent 
the cost of compensated pendulums from seriously inter- 
fering with their use. The result was the pendulum com- 
posed of a steel rod and a quantity of mercury, the latter 
forming the principal weight for the bob and being con- 
tained in steel or glass jars, or jars of cast iron for the 
heavier pendulums. Other metals will not serve the pur- 
pose, as they are corroded by the mercury, become rotten 
and lose their contents. 

Mercury has one deficiency which, however, is not seri- 
ous, except for the severe conditions of astronomical obser- 
vatories. It will oxidize after long exposure to the air, 
when it must be strained and a fresh quantity of metal 
added and the compensation freshly adjusted. To an as- 
tronomer this is a serious objection, as it may interfere with 
his work for a month, but to the jeweler this is of little 
moment as the rates he demands will not be seriously affect- 
ed for about ten years, if the jars are tightly covered. 

To construct a reliable gridiron pendulum would cost 
about fifty dollars while a mercurial pendulum can be well 
made and compensated for about twenty-five dollars, hence 
the popularity of the latter form. 

53 



54; ' THE MODERN CLOCK, 

Zinc will lengthen under severe variations of tempera- 
ture as the following will show: Zinc has a decided objec- 
tionable quality in its crystalline structure that with temper- 
ature changes there is very unequal expansion and con- 
traction, and furthermore, that these changes occur sud- 
deiily; this often results in the bending of the zinc rod,, 
causing a binding to take place, which naturally enough 
prevents the correct working of the compensation. 

It is probably not very well known that zinc can change 
its length at one and the same temperature, and that this 
peculiar quality must not be overlooked. The U. S. Lake 
Survey, which has under its charge the triangulation of the 
great lakes of the United States, has in its possession a steel 
meter measure, R, 1876; a metallic thermometer composed 
of a steel and zinc rod, each being one meter in length,, 
marked M. T., 1876s, and M. T. 1876Z; and four metallic 
thermometers, used in connection with the base apparatus, 
which likewise are made of steel and zinc rods, each of 
these being four meters in length. All of these rods were 
made by Repsold, of Hamburg. Comparisons between these 
different rods show peculiar variations, and which point to 
the fact that their lengths at the same degree of temperature 
are not constant. For the purpose of determining these 
variations accurate investigations were undertaken. The 
metallic thermometer M. T. 1876 was removed from an ob- 
servatory room having an equal temperature of about 2° C. 
and placed for one day in a temperature of 4-24° C, and 
also for the same period of time in one of — 20° C ; it was 
then replaced in the observatory room, where it remained 
for twenty-four hours, and comparisons were made during 
the following three days with the steel thermometer R, 
1876, which had been left in the room. From these obser- 
vations and comparisons the following results were tabu- 
lated, which give the mean leng^ths of the zinc rods of the 
metallic thermometer. The slight variations of temperature 
in the observatory room were also taken into consideration 
in the calculations : 



MODERN CLOCK. ^^^' ^^^SgS 



M. T. 1876s. M. T. 1876Z. 
mm. mm. 

Februar}^ 16-24 — 0.0006 + 0.0152, previous 7 days at + 24°C 

February 25-27 — 0.0017 — o.ooii, previous i day at — 20°C 

March 2-4 + 0.0005 + 0.0154, previous i day at + 24° C. 

March 5-8 — 0.0058 — 0.0022, previous i day at — 20° C. 

These investigations clearly indicate, without doubt, that 
the zinc rod at one and the same temperature of about 2° C, 
is 0.018 mm. longer after having been previously heated to 
24° C. than when cooled before to — 20° C. 

A similar but less complete examination was made with 
the metallic thermometer four meters in length. These 
trials were made by that efficient officer, General Corn- 
stock, gave the same results, and completely prove that in 
zinc there are considerable thermal after-effects at work. 

To prove that zinc is not an efficient metal for compensa- 
tion pendulums when employed for the exact measurement 
of time, a short calculation may be made — using the above 
conclusions — that a zinc rod one meter in length, after 
being subjected to a difference of temperature of 44 C. will 
alter its length 0.018 mm. after having been brought back 
to its initial degree. For a seconds pendulum with zinc 
compensation each of the zinc rods would require a length 
of 64.9 cm. With the above computations we get a differ- 
ence in length of 0.0117 mm. at the same degree of temper- 
ature. Since a lengthening of the zinc rods without a suit- 
able and contemporaneous expansion of the steel rods is 
synonymous with a shortening of the effectual pendulum 
length, we have, notwithstanding the compensation, a short- 
ening of the pendulum length of 0.017 mm., which corre- 
sponds to a change in the daily rate of about 0.5 seconds. 

This will sufficiently prove that zinc is unquestionably 
not suitable for extremely accurate compensation pendu- 
lums, and as neither is permanent under extremes of tem- 
perature the advantages of first cost and of correction of 
error appear to lie with the mercurial form. 



56 THE MODERN CLOCK. 

The average mercurial compensation pendulums, on sale 
in the trade are often only partially compensated, as the 
mercury is nearly always deficient in quantity relatively, 
and not high enough in the jar to neutralize the action of 
the rigid metallic elements, composing the structure. The 
trouble generally is that the mercury forms too small a pro- 
portion of the total weight of the pendulum bob. There 
is a fundamental principle governing these compensating 
pendulums that has to be kept in mind, and that is that one 
of the compensating elements is expected to just undo what 
the other does and so establish through the medium of 
physical things the condition of the ideal pendulum, with- 
out weight or elements outside of the bob. As iron and 
mercury, for instance, have a pretty fixed relative expansive 
ratio, then whatever these ratios are after being found, must 
be maintained in the construction of the pendulum, or the 
results cannot be satisfactory. 

First, there are 39.2 inches of rod of steel to hold the 
bob between the point of suspension and the center of oscil- 
lation, and it has been found that, constructively, in all 
the ordinary forms of these pendulums, the height of mer- 
cury in the bob cannot usually be less than 7.5 inches. Sec- 
ond, that in all seconds pendulums the length of the metal 
is fixed substantially, while the height of the mercury is a 
varying one, due to the differing weights of the jars, 
straps, etc. 

Third, the mercury, at its minimum, cannot with jars of 
ordinary weight be less in height in the jar than 7.5 inches, 
to effectually counteract what the 39.2 inches of iron does 
in the way of expanding and contracting under the same 
exposure. 

Whoever observes the great mass of pendulums of this 
description on sale and in use will find that the height 
of the mercury in the jar is not up to the amount given 
above for the least quantity that will serve under the most 
favorable circumstances of construction. The less weight 



THE MODERN CLOCK. 57 

there is in the rod, jar and frame, the less is the height 
of mercury which is required ; but with most of the pendu- 
lums made in the present day for the market, the height 
given cannot be cut short without impairing the quality and 
efficiency of the compensation. Any amount less will have 
the effect of leaving the rigid metal in the ascendancy ; or, 
in other words, the pendulum will be under compensated 
and leave the pendulum to feel heat and cold by raising and 
lowering the . center of oscillation of the pendulum and 
hence only partly compensating. A jar with only six inches 
in height of mercury will in round numbers only correct the 
temperature error about six-sevenths. 

Calculations of Weights. — As to how to calculate the 
amount of mercury required to compensate a seconds pendu- 
lum, the following explanation should make the matter 
clear to anyone having a fair knowledge of arithmetic only, 
though there are several points to be considered which 
render it a rather more complicated process than would ap- 
pear at first sight. 

1st. The expansion in length of steel and cast iron, as 
given in the tables (these tables differ somewhat in the 
various books), is respectively .0064 and .0066, while mer- 
cury expands .1 in bulk for the same increase of tempera- 
ture. If the mercury were contained in a jar which itself 
had no expansion in diameter, then all its expansion would 
take place in height, and in round numbers it would expand 
sixteen times more than steel, and we should only require 
(neglecting at present the allowance to be explained under 
head 3) to make the height of the mercury — reckoned from 
the bottom of the jar (inside) to the middle of the column 
of mercury contained therein — one-sixteenth of the total 
length of the pendulum measured from the point of sus- 
pension to the bottom of the jar, assuming that the rod and 
the jar are both of steel, and that the center of oscillation 
is coincident with the center of the column of mercury. 



JS THE MODERN CLOCK. 

Practically in these pendulums, the center of oscillation 
is almost identical with the center of the bob. 

2d. As we cannot obtain a jar having no expansion in 
diameter, we must allow for such expansion as follows,, 
and as cast-iron or steel jars of cylindrical shape are un- 
doubtedly the best, we will consider that material and form 
only. 

As above stated, cast iron expands .0066, so that if the 
original diameter of the jar be represented by i, its ex- 
panded diameter will be 1.0066. Now the area of any circle 
varies as the square of its diameter, so that before and after 
its expansion the areas of the jar will be in the ratio of i^ 
to 1.0066^; that is, in the proportion of i to i. 01 3243; or 
in round numbers it will be one-seventy-sixth larger in area 
after expansion than before. It is evident that the mercury 
will then expand sideways, and that its vertical rise will be 
diminished to the same extent. Deduct, therefore, the one- 
seventy-sixth from its expansion in bulk (one-tenth) and we 
get one-eleventh (or more exactly .086757) remaining. 
This, then, is the actual vertical rise in the jar, and when 
compared with the expansion of steel in length it will be 
found to be about thirteen and a half tim.es greater (more 
exactly 13-556). 

The mercury, therefore (still neglecting head No. 3)^ 
must be thirteen and a half times shorter than the length 
of the pendulum, both being measured as explained above. 
The pendulum will probably be 43.5 inches long to the 
bottom of the jar; but as about nine inches of it is cast 
iron, which has a slightly greater rate of expansion than 
steel, we will call the length 44 inches, as the half inch 
added will make it about equivalent to a pendulum entirely 
of steel. If the height of the mercury be obtained by di- 
viding 44 by 13.5, it will be 3.25 inches high to its center, 
or 6.5 inches high altogether; and were it not for the fol- 
lowing circumstance, the pendulum would be perfectly 
compensated. 



THE MODERN CLOCK. 59 

3d. The mercury is the only part of the bob which ex- 
pands upwards; the jar does not rise, its lower end being 
carried downward by the expansion of the rod, which sup- 
ports it. In a well-designed pendulum, the jar, straps, etc.;, 
will be from one-fourth to one-third the weight of the mer- 
cury. Assume them to be seven pounds and twenty-eight 
pounds respectively; therefore, the total weight of the bob 
is thirty-five pounds; but as it is only the mercury (four- 
fifths) of this total that rises with an increase of tempera- 
ture, we must increase the weight of the mercury in the 
proportion of five to four, thus 6.5 X 5 -r- 4 = ^H inches. 
Or, what is the same thing, we add one-fourth to the 
amount of mercury, because the weight of the jar is one- 
fourth of that of the mercury. Eight and one-eighth 
inches is, therefore, the ultimate height of the mercury re- 
quired to compensate the pendulum with that weight of jar. 
If the jar had been heavier, say one-third the weight of the 
mercury, then the latter would have to be nearly 8.75 inches 
high. 

If the jar be required to be of glass, then we substitute 
the expansion of that material in No. 2 and its weight in 
No. 3. 

In the above method of calculating, there are two slight 
elements of uncertainty: ist. In assuming that the center 
of oscillation is coincident with the center of the bob ; how^- 
ever, I should suppose that they would never be more than 
.25 inch apart, and generally much nearer. 2d. The weight 
of the jar cannot well be exactly known until after it is 
finished (i. e., bored smooth and parallel inside, and turned 
outside true with the interior), so that the exact height of 
the mercury cannot be easily ascertained till then. 

I may explain that the reason (in Nos. i and 2) we meas- 
ure the mercury from the bottom to the center of the col- 
umn, is that it is its center which we wish to raise when an 
increase of temperature occurs, so that the center may 
always be exactly the same distance from the point of 



6o THE MODERN CLOCK. 

suspension ; and we have seen that 3.25 inches is the neces- 
sary quantity to raise it sufficiently. Now that center could 
not be the center without it had as much mercury over it as 
it has under it; hence we double the 3.25 and get the 6.5 
inches stated. 

' From the foregoing it will be seen that the average mer- 
cury pendulums are better than a plain rod, from the fact 
that the mercury is free to obey the law of expansion, and 
so, to a certain degree, does counteract the action of the 
balance of the metal of the pendulum, and this with a 
degree of certainty that is not found in the gridiron form, 
provided always that the height and amount of the mer- 
cury are correctly proportional to the total weight of the 
pendulum. 

Compensating Mercurial Pendulums. — To compen- 
sate a pendulum of this kind takes time and study. The 
first thing to do is to place maximum and minimum ther- 
mometers in the clock case, so that you can tell the tem- 
perature. 

Then get the rate of the clock at a given temperature. 
For example, say the clock gains two seconds in twenty- 
four hours, the temperature being at 70°. Then see how 
much it gains when the temperature is at 80°. We will 
say it gains two seconds more at 80° than it does when 
the temperature is at 70°. 

In that case we must remove some of the mercury in 
order to compensate the pendulum. To do this take a 
syringe and soak the cotton or whatever makes the suction 
in the syringe with vaseline. The reason for doing this is 
that mercury is very heavy and the syringe must be air 
tight before you can take any of the mercury up into it. 

You want to remove about two pennyweights of mer- 
cury to every second the clock gains in twenty-four hours. 
Now, after removing the mercury the clock will lose time, 
because the pendulum is lighter. You must then raise the 



THE MODERN CLOCK. 6l 

ball to bring it to time. You then repeat the same opera- 
tion by getting the rate at 76° and 80° again and see if it 
gains. When the temperature rises, if the pendulum still 
gains, you must remove more mercury; but if it should 
lose time when the temperature rises you have taken out 
too much mercury and you must replace some. Continue 
this operation until the pendulum has the same rate, wheth- 
er the temperature is high or low, raising the bob when 
you take out mercury to bring it to time, and lowering the 
bob when you put mercury in to bring it to time. 

To compensate a pendulum takes time and study of the 
clock, but if you follow out these instructions you will suc- 
ceed in getting the clock to run regularly in both summer 
and winter. 

Besides the oxidation, which is an admitted fault, there 
are two theoretical questions which have to do with con- 
struction in deciding between the metallic and mercurial 
forms of compensation. We will present the claims of each 
side, therefore, with the preliminary statement that (for all 
except the severest conditions of accuracy) either form, if 
well made will answer every purpose and that therefore, 
except in special circumstances, these objections are more 
theoretical than real. 

The advocates of metallic compensation claim that where 
there are great differences of temperature, the compensated 
rod, with its long bars will answer more quickly to temper- 
ature changes as follows : 

The mercurial pendulum, when in an unheated room 
and not subjected to sudden temperature changes, gives 
very excellent results, but should the opposite case occur 
there will then be observed an irregularity in the rate of 
the clock. The causes which produce these effects are 
various. As a principal reason for such a condition it may 
be stated that the compensating mercury occupies only 
about one-fifth the pendulum length, and it inevitably fol- 
lows that when the upper strata of the air is warmer than 



^2 THE MODERN CLOCK. 

the lower, in which the mercury is placed, the steel pendu- 
lum rod will expand at a different ratio than the mercury, 
as the latter is influenced by a different degree of tempera- 
ture than the upper part of the pendulum rod. The natural 
effect will be a lengthening of the pendulum rod, notwith- 
standing the compensation, and therefore, a loss of time by 
the clock. 

Two thermometers, agreeing perfectly, were placed in 
the case of a clock, one near the point of suspension, and the 
other near the middle of the ball, and repeated experiments, 
showed a difference between these two thermometers of 7° 
to io^°F.,the lower one indicating less than the higher one. 
The thermometers were then hung in the room, one at 
twenty-two inches above the floor, and the other three feet 
higher, when they showed a difference of 7° between them. 
The difference of 2.5° more which was found inside the 
case proceeds from the heat striking the upper part of the 
case ; and the wood, though a bad conductor, gradually in- 
creases in temperature, while, on the contrary, the cold 
rises from the floor and acts on the lower part of the case, 
The same thermometers at the same height and distance in 
an unused room, which was never warmed, showed no dif- 
ference between them ; and it would be the same, doubtless, 
in an observatory. 

From the preceding it is very evident that the decrease of 
rate of the clock since December 13 proceeded from the rod 
of the pendulum experiencing 7° to 10.5° F. greater heat 
than the mercury in the bob, thus showing the impossibility 
of making a mercurial pendulum perfectly compensating 
in an artificially heated room which varies greatly in tem- 
perature. I should remark here that during the entire 
winter the temperature in the case is never more than 68° 
F., and during the summer, when the rate of the clock was 
regular, the thermometer in the case has often indicated 
72° to yy"" F. 

The gridiron pendulum in this case would seem prefer- 
able, for if the temperature is higher at the top than at the 



THE MODERN CLOCK. 63 

lower part, the nine compensating rods are equally effected 
by it. But in its compensating action it is not nearly as 
regular, and it is very difficult to regulate it, for in any 
room (artificially heated) it is impossible to obtain a uni- 
form temperature throughout its entire length, and with- 
out that all proofs are necessarily inexact. 

These facts can also be applied to pendulums situated in 
heated rooms. In the case of a rapid change in tempera- 
ture taking place in the observatory rooms, under the domes 
of observatories, especially during the winter months, and 
which are of frequent occurrence, a mercurial compensa- 
tion pendulum, as generally made, is not apt to give a re- 
liable rate. Let us accept the fact, as an example, of a 
considerable fall in the temperature of the surrounding air ; 
the thin, pendulum rod will quickly accept the same tempera- 
ture, but with the great mass of mercury to be acted upon 
the responsive effects will only occur after a considerable 
lapse of time. The result will be a shortening of the pendu- 
lum length and a gain in the rate until the mercury has 
had time to respond, notwithstanding the compensation. 

Others who have expressed their views in writing seem 
to favor the idea that this inequality in the temperature of 
the atmosphere is unfavorable to the accurate action of the 
mercurial form of compensation; and however plausible 
and reasonable this idea ma}^ seem at first notice, it will not 
take a great amount of investigation to show that, instead 
of being a disadvantage, its existence is beneficial, and an 
important element in the success of mercurial pendulums. 

It appears that the majority of those who have proposed, 
or have tried to improve Graham's pendulum have over- 
looked the fact that different substances require different 
quantities of heat to raise them to the same temperature. In 
order to warm a certain weight of water, for instance, 
to the same degree of heat as an equal weight of oil, or an 
equal weight of mercury, twice as much heat must be given 
to the water as to the oil, and thirty times as much as to the 



64 THE MODERN CLOCK. 

mercury ; while in cooling down again to a given tempera- 
ture, the oil will cool twice as quick as the water, and the 
mercury thirty times quicker than the water. This phenom- 
enon is accounted for by the difference in the amount of 
latent heat that exists in various substances. On the au- 
thority of Sir Humphrey Davy, zinc is heated and cooled 
again ten and three-quarters times quicker than water, brass 
ten and a half times quicker, steel nine times, glass eight 
and a half times, and mercury is heated and cooled again 
thirty times quicker than water. 

From the above it will be noticed that the difference in 
the time steel and mercury takes to rise and fall to a given 
temperature is as nine to thirty, and also that the difference 
in the quantity of heat that it takes to raise steel and mer- 
cury to a given temperature is in the ratio of nine to thirty. 

Now, without entering into minute details on the prop- 
erties which different substances possess for absorbing or 
reflecting heat, it is plain that mercury should move in a 
proportionally different atmosphere from steel in order to 
be expanded or contracted a given distance in the same 
length of time ; and to obtain this result the amount of dif- 
ference in the temperature of the atmosphere at the opposite 
ends of the pendulum must vary a little more or less accord- 
ing to the nature of the material the mercury jars are con- 
structed from. 

Differences in the temperature of the atmosphere of a 
room will generally vary according to its size, the height 
of the ceiling, and the ventilation of the apartment; and if 
the difference must continue to exist, it is of importance 
that the difference should be uniformly regular. We must 
not lose sight of the fact, however, that clocks having these 
pendulums, and placed in apartments every way favorable 
to an equal temperature, and in some instances, the clocks 
and their pendulums incased in double casing in order to 
more effectually obtain this result, still the rates of the 
clock show the same eccentricities as those placed in less 



THE MODERN CLOCK. 65 

favorable position. This clearly shov/s that many changes 
in the rates of fine clocks are due to other causes than a 
change in the temperature of the surounding atmosphere. 
Still it must be admitted that any change in the condition of 
the atmosphere that surrounds a pendulum is a most formid- 
able obstacle to be overcome by those who seek to improve 
compensated pendulums, and it would be of service to them 
to know all that can possibly be known on the subject. 

The differences spoken of above have resulted in some 
practical improvements, which are: ist, the division of the 
mercury into two, three or four jars in order to expose as 
much surface as possible to the action of the air, so that 
the expansion of the mercury should not lag behind that of 
the rod, which it will do if too large amounts of it are kept 
in one jar. 2nd, the use of very thin steel jars made from 
tubing, so that the transmission of heat from the air to the 
mercury may be hastened as much as possible. 3rd, the in- 
crease in the number of jars makes a thinner bob than a 
single jar of the same total weight and hence gives an ad- 
vantage in decreasing the resistant effect of air friction in 
dense air, thereby decreasing somewhat the barometric 
error of the pendulum. 

The original form of mercurial pendulums, as made by 
Graham, and still used in tower and other clocks where 
extraordinary accuracy is not required, was a single jar 
which formed the bob and had the pendulum rod extending 
into the mercury to assist in conducting heat to the variable 
element of the pendulum. It is shown in section in Fig, 
ii3, which is taken from a working drawing for a tower 
clock. 

The pendulum. Fig. 13, is suspended from the head or 
cock shown in the figure, and supported by the clock frame 
itself, instead of being hung on a wall, since the intention 
is to set the clock in the center of the clockroom, and 
also because the weight, forty pounds, is not too much for 
the clock frame to carry. The head. A, forms a revolving 



66 THE MODERN CLOCK. ' 

thumb-nut, which is divided into sixty parts around the 
circumference of its lower edge, and the regulating screw, 
B, is threaded ten to the inch. A very fine a'djustment is 
thus obtained for regulating the time of the pendulum. The 
lower end of the regulating screw, B, holds the end of the 
pendulum spring, E, which is riveted between two pieces 
of steel, C, and a pin, C, is put through them and the end 
of the regulating screw, by which to suspend the pendulum. 

The cheeks or chops are the pieces D, the lower edges 
of which form the theoretical point of suspension of the 
pendulum. These pieces must be perfectly square at their 
lower edges, otherwise the center of gravity would describe 
1 cylindrical curve. The chops are clamped tightly in place 
by the setscrews, D', after the pendulum has been hung. 

The lower end of the regulating screw is squared to fit the 
ways and slotted on one side, sliding on a pin to prevent its 
turning and therefore twisting the suspension spring when 
it is raised or lowered. 

The spring is three inches long between its points of 
suspension, one and three-eighths inches wide, and one- 
sixtieth of an inch thick. Its lower end is riveted between 
two small blocks of steel, F, and suspended from a pin, F', 
in the upper end of the cap, G, of the pendulum rod. 

The tubular steel portion of the pendulum rod is seven- 
eighths of an inch in diameter and one-thirty-second of an 
inch thickness of the wall. It is enclosed at each end by the 
solid ends, G and L, and is made as nearly air tight as 
possible. 

The compensation is by mercury inclosed in a cast-iron 
bob. The mercury, the bob and the- rod together weigh 
forty pounds. The bob of the pendulum is a cast-iron jar, 
K, three inches in diameter inside, one-quarter inch thick 
at the sides, and five-sixteenths thick at the bottom, with 
the cap, J, screwed into its upper end. The cap, J, forms 
also the socket for the lower end of the pendulum rod, H. 
The rod, L, one-quarter inch in diameter, screws into the 
cap, J, and its large end at the same time forms a plug 



THE MODERN CLOCK. 



67 



■±; 




Fig. 13. 



68 THE MODERN CLOCK. 

for the lower end of the pendulum tube, H. The pin, J', 
holds all these parts together. The rod, L, extends nearly to 
the bottom of the jar, and forms a medium for the trans- 
mission of the changes in temperature from the pendulum 
tube to the mercury. The screw in the cap, J, is for filling 
or emptying the jar. The jar is finished as smoothly as 
possible, outside and inside, and should be coated with at 
least three coats of shellac inside. Of course if one was 
building an astronomical clock, it would be necessary to 
boil the mercury in the jar in order to drive off the layer of 
air between the mercury and the walls of the jar, but with 
the smooth finish the shellac will give, in addition to the 
good work of the machinist, the amount of air held by 
the jar can be ignored. 

The cast-iron jar was decided upon because it was safer 
to handle, can be attached more firmly to the rod with less 
multiplication of parts, and also on account of the weight 
as compared with glass, which is the only other thing that 
should be used, the glass requiring a greater height of jar 
for equal weight. In making cast iron jars, they should al- 
ways be carefully turned inside and out in order that the 
walls of the jar may be of equal thickness throughout; then 
they will not throw the pendulum out of balance when they 
are screwed up or down on the pendulum rod in making 
the coarse regulation before timing by the upper screw. 
The thread on the rod should have the cover of the jar at 
about the center of the thread when nearly to time and 
that portion which extends into the jar should be short 
enough to permit this. 

Ignoring the rod and its parts for the present, and calling 
the jar one-third of the weight of the mercury, we shall 
find that thirty pounds of mercury, at .49 pounds per cubic 
inch, will fill a cylinder which is three inches inside diam- 
eter to a height of 8.816 inches, after deducting for the 
mass of the rod L, when the temperature of the mercury is 
60 degrees F. Mercury expands one-tenth in bulk, while 



THE MODERN CLOCK. 69 

cast-iron expands .0066 in diameter: so the sectional area 
increases as 1,0066^ or 1.0132 to i, therefore the mercury 
will rise .1 — .013243, or .086757; then the mercury in our 
jar will rise .767 of an inch in the ordinary changes of 
temperature, making a total height of 9.58 inches to provide 
for; so the jar was made ten inches long. 

Pendulums of this pattern as used in the high grade 
English clocks, are substantially as follows: Rod of steel 
5-16 inch diameter; jar about 2.1 inches diameter inside 
and 8}i inches deep inside. The jar may be wrought or 
cast iron and about ^ of an inch thick with the cover to 
screw on with fine thread, making a tight joint. The cover 
of the jar is to act as a nut to turn on the rod for regula- 
tion. The thread cut on the rod should be thirty-six to 
the inch, and fit into the jar cover easily, so that it may 
turn without binding. With a thirty-six thread one turn 
of the jar on the rod changes the rate thirty seconds per 
day and by laying ofT on the edge of the cover 30 divisions, 
a scale is made by which movements for one second per 
day are obtained. 

We will now describe (Fig. 14) the method of making a 
mercurial pendulum to replace an imitation gridiron pendu- 
lum for a Swiss, pin escapement regulator, such as is 
commonly found in the jewelry stores of the United States, 
that is, a clock in which the pendulum is supported by the 
plates of the movement and swings between the front plate 
and the dial of the movement. In thus changing our pendu- 
lum, we shall desire to retain the upper portion of the old 
rod, as the fittings are already in place and we shall save 
considerable time and labor by this course. As the pendu- 
lum is suspended from the movement, it must be lig;hter in 
weight than if it were independently supported by a cast 
iron bracket, as shown in Fig. 6, so we will make the 
weig^ht about that of the one we have removed, or about 
twelve pounds. If it is desired to make the pendulum 
heavier, four jars of the dimensions given would make it 



yO THE MODERN CLOCK. 

weigh about twenty pounds, or four jars of one inch diame- 
ter would make a thinner bob and one weighing about 
fourteen pounds. As the substitution of a different number 
or different sizes of jars merely involves changing the 
lengths of the upper and lower bars of the frame, further 
drawings will be unnecessary, the jeweler having sufficient 
mechanical capacity to be able to make them for himself. 

1 might add, however, that the late Edward Howard, in 
building his astronomical clocks, used four jars containing 
twenty-eight pounds of mercury for such movements, and 
the perfection of his trains was such that a seven-ounce 
driving weight was sufficient to propel the thirty pound 
pendulum. 

The two jars are filled with mercury to a height of jYz 
inches, are i% inches in diameter outside and 8% inches in 
height outside. The caps and foot pieces are screwed on 
and when the foot pieces are screwed on for the last time 
the screw threads should be covered with a thick shellac 
varnish which, when dry, makes the joint perfectly air 
tight. The jars are best made of the fine, thin tubing, used 
in bicycles, which can be purchased from any factory, of 
various sizes and thickness. In the pendulum shown in the 
illustration, the jar stock is close to 14 wire gauge, or about 

2 mm. in thickness. In cutting the threads at the ends of the 
jars they should be about 36 threads to the inch, the same 
number as the threads on the lower end of the rod used to 
carry the regulating nut. A fine thread makes the best job 
and the tightest joints. The caps to the jars are turned 
up from cold rolled shafting, it being generally good stock 
and finishes well. The threads need not be over 3-16 inch, 
which is ample. Cut the square shoulder so the caps and 
foot pieces come full up and do not show any thread when 
screwed home. These jars will hold ten pounds of mercury 
and this weight is about right for this particular style of 
pendulum. The jars complete will weigh about seven ounces 
each. 



THE MODERN CLOCK. 



71 




1 



l.lVtfMut 3 

s n 



n 



>=i 






/ , , \ 



\_ ' I 



Fig. 14. 



72 THE MODERN CLOCK. 

The frame is also made of steel and square finished 
stock is used as far as possible and of the quality used in the 
caps. The lower bar of the frame is six inches long and 
5/s inch square at the center and tapered, as shown in the 
illustration. It is made 'light by being planed away on the 
under side, an end view being shown at 3. The top 
bar of the frame, shown at 4, is planed away also and 
is one-half inch square the whole length and is six inches 
long. The two side rods are to bind the two bars together, 
and with the four thumb nuts at the top and bottom make a 
strong light frame. 

The pendulum described is nickel plated and polished, ex,- 
cept the jars, which are left half dead; that is, they are 
frosted with a sand blast and scratch brushed a little. The 
effect is good and makes a good contrast to the polished 
parts. The side rods are five inches apart, which leaves 
one-half inch at the ends outside. 

The rod is 5-16 of an inch in diameter and 33 inches long 
from the bottom of the frame at a point where the regulat- 
ing nut rests against it to the lower end of the piece of the 
usual gridiron pendulum shown in Fig. 14 at 10. This piece 
shown is the usual style and size of those in the majority 
of these clocks and is the standard adopted by the makers. 
This piece is 11% inches long from the upper leaf of the 
suspension spring, which is shown at 12, to the lower end 
marked 10. By cutting out the lower end of this piece, as 
showr at 10, and squaring the upper end of the rod, pin- 
ning it into the piece as shown, the union can be made easily 
and any little adjustments for length can be made by drilling 
another set of holes in the rod and raising the pendulum by 
so doing to the correct point. A rod whose total length 
is 37 inches will leave 2 inches for the prolongation below 
the frame carrying the regulating nut, 9, and for the portion 



THE MODERN CLOCK. 73 

squared at the top, and will then be so long that the rate 
of the clock will be slow and leave a surplus to be cut off 
either at the top or bottom, as may seem best. 

The screw at the lower end carrying the nut should have 
36 threads to the inch and the nut graduated to 30 divisions, 
each of which is equal in turning the nut to one minute in 
24 hours, fast or slow, as the case may be. 

The rod should pass through the frame bars snugly and 
not rattle or bind. It also should have a slot cut so that a pin 
can be put through the upper bar of the frame to keep the 
frame from turning on the rod and yet allow it to move up 
and down about an inch. The thread at the lower end of the 
rod should be cut about two inches in length and when cut- 
ting off the rod for a final length, put the nut in the middle 
of the run of the thread and shorten the rod at the top. 
This will be found the most satisfactory method, for when 
all is adjusted the nut will stand in the middle of its scope 
and have an ^qual run for fast or slow adjustment. With 
the rod of the full length as given, this pendulum had to be 
cut at the top about one inch to bring to a minute or two in 
twenty-four hours, and this left all other points below cor- 
rected. The pin in the rod should be adjusted the last thing, 
as this allows the rod to slide on the pin equal distances each 
way. One inch in the raising or lowering of the frame on 
the rod will alter the rate for twenty- four hours about 
eighteen minutes. 

Many attempts have been made to combine the good qual- 
ities of the various forms of pendulums and thus produce an 
instrument which would do better work under the severe 
exactions of astronomical observatories and master clocks 
controlling large systems. The reader should understand 
that, just as in watch work, the difficulties increase enor- 
mously the nearer we get towards absolute accuracy, and 



74 THE MODERN CLOCK. 

while anybody can make a pendulum which will stay within 
a minute a month, it takes a very good one to stay within 
five seconds per month, under the conditions usually found 
in a store, and such a performance makes it totally unfit for 
astronomical work, where variations of not over five-* 
thousandths of a second per day are demanded. In order 
to secure such accuracy every possible aid is given to the 
pendulum. Barometric errors are avoided by enclosing it in 
an airtight case, provided with an airpump ; the temperature 
is carefully maintained as nearly constant as possible and its 
performance is carefully checked against the revolutions of 
the fixed stars, while various astronomers check their ob- 
servations against each other by correspondence, so that 
each can get the rate of his clock by calculations of obser- 
vations and the law of averages, eliminating personal errors. 

One of the successful attempts at such a combination of 
mercury and metallic pendulums is that of Riefler, as shown 
in Fig. 15, which illustrates a seconds pendulum one-thir- 
tieth of the actual size. 

It consists of a Mannesmann steel tube (rod), bore 16 
mm., thickness of metal i mm., filled with mercury to 
about two-thirds of its length, the expansion of the mercury 
in the tube changing the center of weight an amount suffi- 
cient to compensate for the lengthening of the tube by 
heat, or vice versa. The pendulum, has further, 
a metal bob weighing several kilograms, and shaped to 
cut the air. Below the bob are disc shaped weights, attached 
by screw threads, for correcting the compensation, the 
number of which may be increased or diminished as ap- 
pears necessary. 

Whereas in the Graham pendulum regulation for tem- 
perature is effected by altering the height of the column of 



THE MODERN CLOCK 



75 



mercury, in this pendulum it is effected by 
changing the position of the center of 
weight of the pendulum by moving the 
regulating weights referred to, and thus 
the height of the column of mercury always 
remains the same, except as it is influenced 
by the temperature. 

A correction of the compensation should 
be effected, however, only in case the pen- 
dulum is to show sidereal time, instead of 
mean solar time, for which latter it is cal- 
culated. In this case a weight of no to 
120 grams should be screwed on to correct 
the compensation. 

In order to calculate the effect of the 
compensation, it is necessary to know pre- 
cisely the co-efficients of the expansion by 
heat of the steel rod, the mercury, and the 
material of which the bob is made. 

The last two of these co-efficients of ex- 
pansion are of subordinate importance, the 
two adjusting screws for shifting the bob 
up and down being fixed in the middle of 
the latter. A slight deviation is, therefore, 
of no consequence. In the calculation for 
all these pendulums the co-efficient for the 
bob is, therefore, fixed at 0.000018, and for 
the mercury at 0.00018136, being the clos- 
est approximation hitherto found for chem- 
ically pure mercury, such as that used in 
these pendulums. 
The co-efficient of the expansion of the steel rod is, how- 
ever, of greater importance. It is therefore, ascertained for 
every pendulum constructed in Mr. Riefler's factory, by the 
physikalisch-technische Reichsanstalt at Charlottenburg, 
examinations showing, in the case of a large number of sim- 




Fig. 15. 



76 THE MODERN CLOCK. 

ilar steel rods, that the co-efficient of expansion lies be- 
tween 0.00001034 and 0.00001162. 

The precision with which the measurements are carried 
out is so great that the error in compensation resulting 
from a possible deviation from the true value of the co- 
efficient of expansion, as ascertained by the Reichsanstalt, 
does not amount to over ± 0.0017; and, as the precision 
with which the compensation for each pendulum may be 
calculated absolutely precludes any error of consequence, 
Mr. Riefler is in a position to guarantee that the probable 
error of compensation in these pendulums will not exceed 
± 0.005 seconds per diem and ± j° variation in tem- 
perature. 

A subsequent correction of the compensation is, there- 
fore, superfluous, whereas, with all other pendulums it is 
necessary, partly because the co-efficients of expansion of 
the materials used are arbitrarily assumed ; and partly 
because none of the formulae hitherto employed for calcu- 
lating the compensation can yield an exact result, for the 
reason that they neglect to notice certain important influ- 
ences, in particular that of the weight of the several parts 
of the pendulum. Such formulae are based on the assump- 
tion that this problem can be solved by simple geometrical 
calculation, whereas, its exact solution can be arrived at 
only with the aid of physics. 

This is hardly the proper place for details concerning 
the lengthy and rather complicated calculations required 
by the method employed. It is intended to publish them 
later, either in some mathematical journal or in a separate 
pamphlet. Here I will only say that the object of the 
whole calculation is to find the allowable or requisite weight 
of the bob, i. e., the weight proportionate to the co-efficients 
of expansion of the steel rod, dimensions and weight of the 
rod and the column of mercury being given in each sep- 
arate case. To this end the relations of all the parts of the 



THE MODERN CLOCK. 77 

pendulum, both in regard to statics and inertia, have to be 
ascertained, and for various temperatures. 

A considerable number of these pendulums have already 
been constructed, and are now running in astronomical ob- 
servatories. One of them is in the observatory of the Uni- 
versity of Chicago, and others are in Europe. The precision 
of this compensation which was discovered by purely theo- 
retical computations, has been thoroughly established by the 
ascertained records of their running at different temper- 
atures. 

The adjustment of the pendulums, which is, of course, 
almost wholly without influence on the compensation, can 
be effected in three different ways: 

(i.) The rough adjustment, by screwing the bob up or 
down. 

(2.) A finer adjustment, by screwing the correction 
discs up or down. 

(3.) The finest adjustment, by putting on additional 
weights. 

These weights are to be placed on a cup attached to a 
special part of the rod of the pendulum. Their shape and 
size is such that they can be readily put on or taken off 
while the pendulum is swinging. Their weight bears a 
fixed proportion to the static momentum of the pendulum, 
so that each additional weight imparts to the pendulum, for 
iwenty-four hours, an acceleration expressed in even sec- 
onds and parts of seconds, and marked on each weight. 

Each pendulum is accompanied with additional weights 
of German silver, for a daily acceleration of i second each, 
and ditto of aluminum for an acceleration of 0.5 and 0.1 
second respectively. 

A metal clasp attached on the rear side of the clock-case, 
may be pushed up to hold the pendulum in such a way that 
it can receive no twisting motion during adjustment. 

Further, a pointer is attached to the lower end of the 
pendulum, for reading off the arc of oscillation. 



78 THE MODERN CLOCK. 

The essential advantages of this pendulum over the mer- 
curial compensation pendulums are the following : 

(i.) It follows the changes of temperature more rap- 
idly, because a small amount of mercury is divided over a 
greater length of pendulum, whereas, in the older ones the 
entire (and decidedly larger) mass of mercury is situ- 
ated in a vessel at the lower end of the pendulum rod. 

(2.) For this reason differences in the temperature of 
the air at different levels have no such disturbing influence 
on this pendulum as on the others. 

(3.) This pendulum is not so strongly influenced as 
the others by changes in the atmospheric pressure, because 
the principal mass of the pendulum has the shape of a lens, 
and therefore cuts the air easily. 



CHAPTER V. 

REGULATIONS, SUSPENSIONS, CRUTCHES AND MINOR POINTS. 

Regulation. — The reader will have noticed that in de- 
scribing the various forms of seconds pendulums we have 
specified either eighteen or thirty-six threads to the inch; 
this is because a revolution of the nut with such a thread 
gives us a definite proportion of the length of the rod, so 
that' it means an even number of seconds in twenty-four 
hours. 

Moving the bob up or down 1-18 inch makes the clock 
having a seconds pendulum gain or lose in twenty-four 
hours one minute, hence the selecting definite numbers of 
threads has for its reason a philosophical standpoint, and is 
not a matter of convenience and chance, as seems to be the 
practice with many clockmakers. With a screw of eighteen 
threads, we shall get one minute change of the clock's 
rate in twenty-four hours for every turn of the nut, and 
if the nut is divided into sixty parts at its edge, each of 
these divisions will make a change of the clock's rate of one 
second in twenty-four hours. Thus by using a thread 
having a definite relation to* the length of the rod regu- 
lating is made comparatively easy, and a clock can be 
brought to time without delay. Suppose, after comparing 
your clock for three or four days with some standard, 
you find it gains twelve seconds per day, then, turning the 
nut down twelve divisions will bring the rate down to 
within one second a day in one operation, if the screw is 
eighteen threads. With the screw thirty-six threads the 
nut will require moving just the same number of divisions, 
only the divisions are twice as long as those with the screw 
of eighteen threads. 

79 



8o THE MODERN CLOCK. 

The next thing is the size and weight of the nut. If it is 
to be placed in the middle of the bob as in Figs. lo, 12 and 
15, it should project slightly beyond the surface and its 
diameter will be governed by the thickness of the bob. If 
Jt is an internal nut, worked by means of a sleeve and disc, 
as in Fig. 9, the disc . should be of sufficient diameter to 
make the divisions long enough to be easily read. If the 
nut is of the class shown in Fig. 5, 6, 7, a nut is most con- 
venient, I inch in diameter, and cut on its edge into thirty 
equal divisions, each of which is equal to one second in 
change of rate in twenty-four hours, if the screw has thirty- 
six threads to the inch. This gives 3.1416 inches of cir- 
cumference for the thirty divisions, which makes them long 
enough to be subdivided if we choose, each division being a 
little over one-tenth of an inch in length, so that quarter- 
seconds may be measured or estimated. 

With some pendulums, Fig. 13, the bob rotates on the 
rod, and is in the form of a cylinder, say 8^ inches long 
by 25^ inches in diameter, and the bob then acts on its rod 
as the nut does, and moves up and down when turned, and 
in this form of bob the divisions are cut on the outside edge 
of the cover of the bob, and are so long that each one is sub- 
divided into five or ten smaller divisions, each altering the 
clock .2 or .1 second per day. 

On the top of the bob turn two deep lines, close to the 
edge, about 5^ -inch apart, and divide the whole diameter 
into thirty equal divisions, and subdivide each of the thirty 
into five, and this will give seconds and fifths of seconds 
for twenty-four hours. Each even seconds division should 
be marked heavier than the fraction, and should be marked 
from one to thirty with figures. Just above the cover on 
the rod should slide a short tube, friction tight, and to this 
a light index or hand should be fastened, the point of which 
just reaches the seconds circle on the bob cover, and thus 
indicates the division, its number and fraction. The tube 
slides on the rod because the exact place of the hand can- 



THE MODERN CLOCK. 8l 

not be settled until it has been settled by experiment. After 
this it can be fastened permanently, if thought best, though 
as described it will be all sufficient. While the bob is being 
raised or lowered to bring the clock to its rate, the bob 
might get too far away or too near to the index and neces- 
sitate its being shifted, and if friction tight this can be read- 
ily accomplished, and the hand be brought to just coincide 
with the divisions and look well and be a means of accom- 
plishing very accurate minute adjustments. 

Suspensions. — Suspensions are of four kinds, cord, wire 
loop, knife edges and springs. Cords are generally of 
loosely twisted silk and are seldom found except in the 
older clocks of French or Swiss construction. They have 
been entirely displaced in the later makes of European 
manufactures by a double wire loop, in which the pendu- 
lum swings from a central eye in the loop, while the loop 
rocks upon a round stud by means of an eye at each end 
of the loop. The eyes should all be in planes parallel to the 
plane of oscillation of the pendulum, otherwise the bob will 
take an elliptical path instead of oscillating in a plane. They 
should also be large enough to roll without friction upon 
the stud and center of the loop, as any slipping or sliding 
of either will cause them to soon wear out, besides affecting 
the rate of the pendulum. Properly constructed loops will 
give practically no friction and make a very free suspension 
that will last as long as the clock is capable of keeping 
time, although it seems to be a very weak and flimsy 
method of construction at first sight. Care should be taken 
in such cases to keep the bob from turning when regulating 
the clock, or the effect. upon the pendulum will be the same 
as if the eyes were not parallel. 

Knife-edge suspensions are also rare now, having been 
displaced by the spring, as it was found the vibrations were 
too free and any change in power introduced a circular error 
(See Fig. 4) by making the long swings in longer time. 



82 THE MODERN CLOCK. 

They are still to be found, however, and in repairing clocks 
containing them the following points should be observed : 
The upper surface of the stud on which the pendulum 
swings should carry the knife edge at its highest point, 
exactly central with the line of centers of the stud, so that 
when the pendulum hangs at rest the stud shall taper equally 
on both sides of the center, thus giving equal freedom to 
both sides of the swing. Care should be taken that the stud 
is firmly fixed, with the knife edge exactly at right angles 
to the movement, and also to the back of the case. The sus- 
pension stud and the block on the rod should be long enough 
to hold the pendulum firmly in line, as the angle in the top 
of the rod must be the sole means of keeping the pendu- 
lum swinging in plane. The student will also perceive the 
necessity of making the angle occupy the proper position 
on the rod, especially if the latter be flat. In repairing 
this suspension it is usual to make the plate, fasten it in 
place and then drill and file out the hole, as it is easier to 
get the angles exactly in this way than to complete the 
plate and then attempt to fasten it in the exact position in 
which it should be. After fastening the plates in position 
on the rod, two holes should be drilled, a small one at the 
apex of the angle (which must be exactly square and true 
with the rod), and a larger one below it large enough to 
pass the files easily. The larger hole can then be enlarged 
to the proper size, filing the angle at the top in such a way 
that the small hole first drilled forms the groove at the 
apex of the angle in which the knife edge of the stud shall 
v/ork when it is completed. Knife-edge suspensions are 
unfitted for heavy pendulums, as the weight causes the 
knife edge to work into the groove and cut it, even if the 
latter oe jeweled. Both the edge and groove should bt 
hardened and polished. 

Pendulum Suspension Springs. — Next in importance 
to the pendulum is its suspension spring. This spring 



THE MODERN CLOCK. 83 

should be just stiff enough to make the pendulum swing in 
all its vibrations in the sam.e time ; that is, if the pendulum 
at one time swung at the bottom of the jar i^ inch each 
side of the center, and at another time it swung only i inch 
each side, that the two should be made in exactly one 
second. The suspension springs are a point in the con- 
struction of a fine pendulum, that there has been very 
much theorizing on, but the experiments have never thus far 
exactly corroborated the theories and there are no definite 
rules to go by, but every maker holds to that plan and con- 
struction that gives his particular works the best results. A 
spring of sufficient strength to materially influence the 
swing of the pendulum is of course bad, as it necessitates 
more power to give the pendulum its proper motion and 
hence there is unnecessary wear on the pallets and escape 
wheel teeth, and too weak a spring is also bad, as it would 
not correct any inequalities in the time of swing and would 
in time break from overloading, as its granular structure 
would finally change, and rupture of the spring would fol- 
low. The office of a spring is to sustain the weight without 
detriment to strength and elasticity, and if so proportioned 
to the weight as to be just right, it will make the long and 
short swings of the pendulum of equal duration. When a 
pendulum hung by a cord or knife edge insttad of a spring 
is regulated to mean time and swings just two inches at the 
bottom, any change in the power that swings the pendu- 
lum will increase its movement or decrease it, and in either 
case the rate will change, but with a proper spring the rate 
will be constant under like conditions. The action of the 
spring is this: In the long swings the spring, as it bends, 
lifts the pendulum bob up a little more than the arc of the 
normal circle in which it swings, and consequently when 
the bob descends, in going to the center of its swing, it falls 
a little quicker than it does when held by a cord, and this 
extra quick drop can be made to neutralize the extra time 
taken by the bob in making extra long swings. See Fig. 4. 



84 



THE MODERN CLOCK. 



This action is the isochronal action of the spring, the same 
that is attained in isochronal hair springs in watches. 

As with the hairspring, it is quite necessary that the pen- 
dulum spring be accurately adjusted to isochronism and my 
advice to every jeweler is to thoroughly test his regulator, 
which can easily be done by changing the weight or motive 
power. If the test should prove the lack of isochronism he 
can adjust it by following these simple rules. Fig. i6 is the 
pendulum spring or leaf. If the short arcs should prove the 
slowest, make the spring a trifle thinner at B ; if fastest, re- 
duce the thickness of the spring at A. Continue the test 
until the long and short arcs are equal. In doing this care 
must be taken to thin each spring equally, if it is a double 
spring, and each edge equally, if a single spring, as if one 
side be left thicker than the other the pendulum will wabble. 

The cause of a pendulum wabbling is that there must be 
something wrong with the suspension spring, or the bridge 



B-A 




a 



Err 



□ E 



Fig, 16. 



that holds the spring. If the suspension spring is bent or 
kinked, the pendulum will wabble ; or if the spring should 
be of an unequal thickness it will have the same effect on 
the pendulum; but the main cause of the pendulum wab- 
bling in American clocks is that the slot in the bridge that 
holds the spring, or the slot in the slide that works up and 
down on the spring (which is used to regulate the clock) is 
not parallel. When this slot is not parallel it pinches the 
spring, front or back, and allows it to vibrate more where 
it is the freest, causing the pendulum to wabble. We have 



THE MODERN CLOCK. 85 

found that by making these slots parallel the wabbling of the 
pendulum has ceased in most all cases. If the pallet staff 
is not at right angles to the crutch, wabbling may be caused 
by the oblique action of the crutch. This often happens 
when the movement is not set square in the case. 

It occasionally happens in mantel clocks that the pendu- 
lum when brought to time is just too long for the case when 
too thick a spring is used. In such a case thinning the 
spring will require the bob to be raised a little and also 
give a better motion. If compelled to make a spring use 
a piece of mainspring about .007 thick and ^ wide for 
small pendulums and the same spring doubled for heavier 
pendulums, making the acting part of the spring about 1.5 
inches long. 

The suspension spring for a rather heavy pendulum is 
better divided, that is, two springs, held by two sets of 
clamps, and jointly acting as one spring. The length will 
be the same as to the acting part, and that part held at each 
end by the clamps may be ^ inch long; total length, 1.5 
inches with ^ inch at each end held in the clamps. These 
clamps are best soldered on to the spring with very low 
flowing solder so as not to draw the temper of the spring, 
and then two rivets put through the whole, near the lower 
edge of the clamps. The object of securing the clamps 
so firmly is so that the spring may not bend beyond the 
edge of the clamps, as if this should take place the clock will 
be thrown off of its rate. After a time the rate would 
settle and become steady, but it only causes an extra period 
of regulating that does not occur when the clamps hold 
the spring immovable at this point. About in the center of 
each of the clamps, when soldered and riveted, is to be a 
hole bored for a pin, which pins the clamp into the bracket 
and holds the weight of the pendulum. 

The width of this compound spring for a seconds' pendu- 
lum of average weight may be .60 inch, from outside to 
outside, each spring .15 inch wide. This will separate the 



86 



THE MODERN CLOCK. 



Springs .30 inch in the center. With this form of spring, 
the lower end of each spring being held in a pair of clamps, 
the clamps will have to be let into the top of the roa, and 
held in by a stout pin, or the pendulum finished with a hook 
which will fit the clamp. In letting the clamp into the 
rod, the clamp should just go into the mortise and be with- 
out side shake, but tilt each way from the center a little 
on the pin, so that when the pendulum is hung it may hang 
perpendicular, directly in the center of both springs. Also, 
the top pair of clamps should fit into a bracket without 
shake, and tilt a little on a pin, the same as the lower clamps. 
These two points, each moving a little, helps to take any 
side twist away, and allows the whole mechanism to swing 
in line with the center of gravity of the mass from end to 
end. With the parts well made, as described, the bob will 
swing in a straight line from side to side, and its path will 
be without any other motion except the one of slight curva- 
ture, due to being suspended by a fixed point at the upper 
clamp. 

Pendulum Supports. — Stability in the movement and in 
the suspension of the pendulum is very necessary in all 
forms of clocks for accurate time-keeping. The pendulum 
should be hung on a bracket attached to the back of the 
case (see Fig. 6), and not be subject to disturbance when 
the movement is cleaned. Also the movement should rest 
on two brackets attached to the bracket holding the pendu- 
lum and the whole be very firmly secured to the back board 
of the case. Screws should go through the foot-pieces of 
the brackets and into a stone or brick wall and be very 
firmly held against the wall just back of the brackets. Any 
instability in this part of a clock is very productive of poor 
rates. The bracket, to be in its best form, is made of cast 
iron, with a large foot carrying all three separate brackets, 
well screwed to a strong back-board and the whole secured 
to the masonry by bolts. Too much firmness cannot be 



THE MODERN CLOCK. 87 

attained, as a lack of it is a. very great fault, and many a 
good clock is a very poor time-keeper, due to a lack of firm- 
ness in its supports and fastenings. The late Edward How- 
ard used to make his astronomical clocks with a heavy cast 
iron back, to which the rest of the case was screwed, so 
that the pendulum should not swing the case. Any external 
influence that vibrates a wall or foundation on which a clock 
is placed, is a disturbing influence, but an instability in a 
clock's attachment to such supports is a greater one. Many 
pendulums swing the case in which they hang (from un- 
stable setting up) and never get down to or maintain a 
satisfactory rate from that cause. This is also aggra- 
vated by the habit of placing grandfather clocks on stair 
landings or other places subject to jarring. The writer 
knows of several clocks which, after being cleaned, kept 
stopping until raised off the floor and bolted to the wall, 
when they at once took an excellent rate. The appearance 
of resting on the floor may be preserved, if desirable, by 
raising the' clock only half an inch or so, just enough to 
free it from the floor. 

Crutches. — The impulse is transmitted to the pendulum 
from the pallet staff by means of a wire, or slender rod, 
fastened at its upper end to the pallet staff and having its 
lower end terminating in a fork (crutch), loop, or bent 
at right angles so as to work freely in a slot in the rod. 
It is also called the verge w^re, owing to the fact that older 
writers and many of the older workmen called the pallet 
fork the verge, thus continuing the older nomenclature, 
although of necessity the verge disappeared when the crown 
wheel was discarded. 

In order to avoid friction at this very important point, 
the centers of both axes of oscillation, that of the pallet 
arbor and fet of the pendulum spring, where it bends, 
should be in a straight horizontal line. If, for instance, the 
center of suspension of the pendulum be higher, then the 



88 THE MODERN CLOCK. 

fork and the pendulum describe two different arcs of circles ; 
that of the pendulum will be greater than that of the fork 
at their meeting point. If, however, the center of suspen- 
sion of the pendulum be lower than that of the fork, they 
will also describe two different arcs, and that of the pendu- 
lum will be smaller than that of the fork at their point of 
meeting. This, as can be readily understood, will cause 
friction in the fork, the pendulum going up and down in it. 
This is prevented when, as stated before, the center of sus- 
pension of the pendulum is in the prolonged straight imagin- 
ary line going through the center of the pivots of the fork, 
which will cause the arcs described by the fork and the pen- 
dulum to be the same. It will be well understood from the 
foregoing that the pendulum should neither be suspended 
higher nor lower, nor to the left, nor to the right of the 
fork. 

If the centers of motion do not coincide, as is often the 
case with cheap clocks with recoil escapements, any rough- 
ness of the pendulum rod where it slides on the crutch 
will stop the clock, and repairers should always see to it 
that this point is made as smooth as possible and be very 
slightly oiled when setting up. If putting in a new verge 
wire, the workman can always tell where to bend it to form 
the loop by noticing where the rod is worn and forming the 
loop so that it will reach the center of that old crutch or 
loop mark on the pendulum rod. If the verge wire is too 
long, it will give too great an arc to the pendulum if the 
latter is hung below the pallet arbor, as is generally the case 
with recoil escapements of the cheap clocks, and if it is too 
short there will not be sufficient power applied to the pendu- 
lum when the clock gets dirty and the oil dries, in which 
case the clock will stop before the spring runs down. 

An important thing to look after when repairing is in the 
verge wire -and loop (the slot the pendulum rod goes 
through). After the clock is set up and oiled, put it on a 
level shelf; have a special adjusted shelf for this level ad- 



THE MODERN CLOCK. S9 

justing, one that is absolutely correct. Have the dial off. 
If the beat is off on one side, so that it bangs up heavily on 
one side of the escape wheel, bend the verge wire the same 
way. That will reverse the action and put it in beat. 
So far so good — but don't stop now. Just notice whether 
if that shelf were tipped forward or back, as perhaps your 
customer's may, that the pendulum should still hang plumb 
and free. Now if the top of your clock tips forward, the 
pendulum ball inclines to hang out toward the front. We 
will suppose you put two small wedges under the back of the 
case. Now notice in its hanging out whether the pendulum 
rod pinches or bears in the throat of the verge ; or if it tips 
back, see if the rod hits the other end of the slot. This 
verge slot should be long enough, with the rod hanging in 
the middle when adjusted to beat on a level, to admit of the 
clock pitching forward or back a little without creating a 
friction on the ends of the slot. This little loop should 
be open just enough to be nice and free; if open too much, 
you will notice the pallet fork will make a little jump when 
carrying the ball over by hand. This is lost motion. If this 
little bend of wire is not parallel it may be opened enough 
inside, but if pitched forward a little it will bind in the nar- 
rowest part of the V and then the clock will stop. The clock 
beat and the tipping out or in of the clock case, causing a 
binding or bearing of the pendulum rod in this verge throat, 
does more towards stopping clocks just repaired than all 
other causes. 

Putting in Beat. — To put a clock in beat, hang the clock 
in such a position that when the pendulum is at rest one 
tooth of the escape wheel will rest on the center of a pallet 
stone. Screwed on the case of the clock at the bottom of 
the pendulum there is, or should be, an index marked with 
degrees. Now, while the escape-wheel tooth is resting on 
the pallet, as explained above, the index of the pendulum 
should point to zero on the index. Move the pendulum until 



90 



THE MODERN CLOCK. 



the tooth just escapes and note how many degrees beyond 
zero the pendulum point is. Say it escapes 2° to the left; 
now move the pendulum until the next tooth escapes — it 
should escape 2° to the right. But let us suppose it does not 
■escape until the index of the pendulum registers 5° to the 
right of zero. In this case the rod attached to the pallets 
must be bent until the escape wheel teeth escape when the 
pendulum is moved an even number of degrees to the right 
and left of zero, when the clock will be in beat. 

Close Rating with Shot. — V^ery close rating of a sec- 
onds' pendulum, accompanied by records in the book, may 
be got with the nut alone, but there is the inconvenience of 
stopping the clock to make an alteration. This may be avoid- 
ed by having a small cup the size of a thimble or small pill 
box on the pendulum top. This can be lifted off and put 
back without disturbing the motion of the pendulum. In 
using it a number of small shot, selected of equal size, are 
put in, say 60, and the clock brought as nearly as possible 
to time by the nut. After a few days the cup may be 
emptied and put back, when on further trial the value of the 
60 shot in seconds a day will be found. This value divided 
by 60 will give the value of a single shot, by knowing which 
very small alterations of rate may be made with a definite 
approach towards accuracy, and in much less time than by 
putting in or taking out one or more shot at random. 



CHAPTER VI. 

TORSION PENDULUMS FOR FOUR HUNDRED DAY CLOCKS. 

As this pendulum is only found in the 400-day, or annual 
wind, or anniversary clocks (they are known by all of these 
names), it is best to describe the pendulum and movement 
together, as its relations to the work to be done may be 
more easily perceived. 

Rotating pendulums of this ki|id — that is, in which the 
bob rotates by the twisting of the suspension rod or spring 
— will not bear comparison with vibrating pendulums for ac- 
curate time keeping. They are only used when a long 
period between windings is required. Small clocks to go 
for twelve months with one winding have the torsion pen- 
dulum ribbons of flat steel about six inches long, making 15 
beats per minute. The time occupied in the beat of such a 
pendulum depends on the power of the suspending ribbon 
to resist twisting, and the weight and distance from the 
center of motion of the bob. In fact, the action of the 
bob and suspending ribbon is very analogous to that of a 
balance and balance spring. 

In order to get good time from a clock of this character, 
it should be made with a dead-beat escapement. With such 
an escapement there is no motion of the escape wheel, after 
the tooth drops on the locking face of the pallet ; the escape 
wheel is dead and does not move again until it starts to 
give the pallet impulse. This style of an escapement allows 
the pendulum as much freedom to vibrate as possible, as 
the fork in one form of this escapement may leave the 
pallet pin as soon as the latter strikes the guard pins, as 
in the ordinary lever escapement of a watch, and it will 
remain in that position until the return of the fork unlocks 

91 



93 



THE MODERN CLOCK. 



the escapement to receive another impulse. B, Fig. 17, 
represents the escape wheel; C, the pallet; E, pallet staff; 
D, the pallet pin rivetted on to the pallet staff E, which 
works in the slot or fork H; this fork is screwed fast to 

in 



L 



!=ii;iuMfj%Miii,m ^: — iMnmfi pi, i ,m i i => 



Fig. 17. 

the spring. The spring G is made of a piece of flat steel 
wire and looks like a clock hairspring straightened out. G 
is fast to the collar I and rests on a seat screwed to the 
plate of the clock, as shown at P ; the spring is also fast- 
ened to the pendulum ball O with screw?; the ball makes 



THE MODERN CLOCK, 



93 



about one and one-half revolutions each beat, which causes 
the spring to twist. It twists more at the point S than it 
does at L; as it twists at L it carries the fork with it, so 
that the latter vibrates from one side to the other^ similar 
to a fork in a watch. This fork H carries the pin D, which 
is fast to the pallet staff E, far enough to allow the teeth 
to escape. 




Fig. 18. 

In the most common form of this escapement, see Fig. 
1 8, the fork does not allow the pin D to leave the slot H, 
and the beat pins are absent, the pendulum not being as 
highly detached as in the form previously mentioned. In 
this case great care must be taken to have the edges of the 
slot, which slide on the pallet pin, smooth, parallel and 
properly beveled, so as not to bind on the pin. The pen- 
dulum ball makes from eight to sixteen vibrations a min- 
ute. Of course the number depends upon the train of the 
clock. 

In suspending the pendulum it is necessary to verify the 
drop of the teeth of the escape wheel as follows : The pen- 
dulum is suspended and the locking position of the pallets 



94 



THE MODERN CLOCK. 



marked, taking as a guiding point the long, regulating 
screw, which, fixed transversely in the support, serves for 
adjusting the small suspension block. An impulse of about 
a third of a turn is given to the pendulum while observing 
the escap'ement. If -the oscillations of the pendulum, meas- 
ured on the two sides, taking the locking point as the base, 
are symmetrical, the drop is also equal, and the rate of the 
clock regular and exact ; but if the teeth of the escape wheel 
are unlocked sooner on one side than on the other, so that 
the pendulum in its swing passes beyond the symmetrical 




Fig. 19. 



point on one of the pallets and does not reach it on the 
other, it is necessary to correct the unequal drop. 

The suspension block B, .Fig. i8, between the jaws of 
which the steel ribbon is pressed by two screw^s, has a lower 
cylindrical portion, which is fitted in a hole made in the 
seat, and is kept immovable by the screw A. If the vibra- 
tion of the pendulum passes beyond the proper point on the 
left side, it is necessary to loosen A and turn the sus- 
pension block slightly to the right. If the deviation is 
produced in the opposite direction, it is necessary to turn 



THE MODERN CLOCK, 



95 



it to the left. These corrections should be repeated until 
the drop of the escape wheel teeth on the pallets is exactly 
equal on the two sides. As the drop is often disturbed by 
the fact that the long thin steel ribbon has been twisted 
in cleaning, taking apart or handling by unskilled persons 
before coming to the watchmaker, it is desirable to test the 
escapement again, when the clock is put into position on 
the premises of the buyer. 

The timing adjustment of the pendulum is effected with 
the aid of regulating weights, placed on the ball. By mov- 
ing these away from the center by means of a right and 
left hand screw on the center of the disk (see Fig. 19), 




Fig. 20. 



the centrifugal force is augmented, the oscillations .of the 
pendulum slackened, and the clock goes slower. The con- 
trary effect is produced if the weights are brought nearer 
the center. In one form of ball the shifting of the regu- 
lating weights is accomplished by a compensating spring of 
steel and brass like the rim of a watch balance. Fig. 20. 

If necessary to replace the pendulum spring, the adjust- 
ment is commenced by shortening or lengthening the steel 
ribbon to a certain extent. For this purpose the end of 
the spring is allowed to project above the suspension block 
as a reserve until adjustment has been completed, when it 
may be cut off. If the space between the ball and the bot- 
tom of the case, or the bottom of the movement plates, does 



g6 THE MODERN CLOCK. 

not allow of attaining this end, it is necessary to increase 
or decrease the weight of the disk, adding one or several 
plates of metal in a depression made in the under side of 
the ball, and removing the plates screwed to it, which are 
too light. 

There are some peculiarities of the trains of these clocks. 
The cannon pinion is provided with a re-enforcing spring, 
serving as guide to the dial work, on which it exercises a 
sufficient pressure to assure precise working. The pressure 
of this spring is important, because if the dial work presses 
too hard on the pinion of the minute wheel, the latter en- 
gaging directly with the escape wheel, would transmit to the 
latter all the force employed in setting the hands. The 
teeth of the escape wheel would incur damage and the con- 
sequent irregularity or even stopping of the clock would 
naturally follow. 

In order that it may run for so long a time, the motive 
force is transmitted through the train by the intervention 
of three supplementary wheels between the minute wheel 
and the barrel, in order to avoid the employment of too large 
a barrel; the third wheel is omitted; the motion work is 
geared immediately with the arbor of the escape wheel. 
It is evident that the system of the three intermediate 
wheels, of which we have spoken, requires for the motive 
force a barrel spring much stronger than that of ordinary 
clocks. 

The points which we have noticed are of the most im- 
portanc-e with reference to the repair and keeping in order 
of an annual clock. It very often happens that when the 
repairer does not understand these clocks, irregularities are 
sought for where they do not exist. The pivot holes are 
bushed and the depthings altered, when a more intelligent 
examination would show that the stopping, or the irregular 
rate of the clock, proceeds only from the condition of the 
escapement. Unless, however, they are perfectly adjusted, 



THE MODERN CLOCK. 97 

a variation of five minutes a week is a close rate for them, 
and most of those in use will vary still more. 

Annual clocks are enjoying an increased favor with the 
public; their good qualities allow confidence, the rate being 
quite regular when in proper order. They are suitable for 
offices ; their silent running recommends them for the sick 
chamber, and the subdued elegance of their decoration 
causes the best of them to be valued ornaments in the home. 



-gahd e: Loo^ ih 

i^i2u't:ikRirit§''m 'AnGVtLkR MEAsuREMEWt— lidw'-- Tcf-^^^i) 
iv'^- DRAWINGS. .i^cirriGd:) 

"'We now come to a point at which, if we are to keep our 
pendulum vibrating, we must apply power to it, evenly, ac- 
curately and in small doses. In order to do this convenient- 
ly we must store up energy by raising a weight or winding 
a spring and allow the weight to fall or the spring to un- 
wind very slowly, say in thirty hours or in eight days. This 
brings about the necessity of changing rotary motion to 
reciprocating motion, and the several devices for doing this 
are called "escapements" in horology, each being further 
designated by the names of their inventors, or by some 
peculiarity of the devices themselves ; thus, the Graham is 
also called the dead beat escapement; Lepaute's is the pin 
wheel; Dennison's in its various forms is called the gravity; 
Hooke's is known as the recoil ; Brocot's as the visible 
escapement, etc. 

The Mechanical Elements. — We shall understand this 
subject more clearly, perhaps, if we first separate these 
mechanical devices into their component parts and consider 
them, not as parts of clocks, but as various forms of levers, 
which they really are. This is perhaps the best place to- 
consider the levers we are using to transmit the energy 
to the pendulum, as at this point we shall find a greater va- 
riety of forms of the lever than in any other place in the 
clock, and we shall have less difficulty in understanding the 
methods of calculating for time and power by a thorough 
preliminary understanding of leverage and the peculiarities 
of angular or circular motion. 

9S 



THE MODERN CLOCK. 



99 



If we take a bar, A, Fig. 21, and place under it a ful- 
crum, B, then by applying at C a given force, we shall be 
able to lift at D a weight whose amount will be governed 
by the relative distances of C and D from the fulcrum B. 



C 



Fig. 21. 

If the distance CB is four times that of BD, then a force 
of 10 pounds at C will lift 40 pounds at D, for one-fourth 
of the distance through which C moves, minus the power 
lost by friction. The reverse of this is also true; that is, 
it will take 40 pounds at D to exert a force of 10 pounds 



- Fig. 22. 

at C and the 10 pounds would be lifted four times as far 
as the 40 pound weight was depressed. 

If instead of a weight we substitute other levers. Fig. 22, 
the result would be the same, except that we should move 
the other levers until the ends which were in contact 
slipped apart. 

II 
^ ' J A 



^D 



Fig. 23. 



If we divide our lever and attach the long end to one 
portion of an axle, as at A, Fig. 23, and the short end to 
another part of it at B, the result will be the same as long 



lOO THE MODERN CLOCK. 

as the proportions of the lever are not changed. It will 
still transmit power or impart motion according to the 
relative lengths of the two parts of the lever. The capacity 
of our levers, Fig. 22, will be limited by that point at which 
the ends of the levers will separate, because they are held 
at the points of the fulcrums and constrained to move in 
circles by the fulcrums. If we put more levers on the 
same axles, so spaced that another set will come into action 
as the first pair are disengaged, we can continue our trans- 
mission of power. Fig. 24; and if we follow this with still 



Fig. 24. 

others until we can add no more for want of room we shall 
have wheels and pinions, the collection of short levers form- 
ing the pinion and the group of long levers forming the 
wheel, Fig. 25. Thus every wheel and pinion mounted to- 
gether on an arbor are simply a collection of levers, each 
wheel tooth and its corresponding pinion leaf forming one 
lever. This explains why the force decreases and the mo- 
tion increases in proportion to the relative lengths of the 
radii of the wheels and pinions, so that eight or ten turns of 
the barrel of a clock will run the escape wheel all day. 

We now come to the verge or anchor, and here we have 
the same sort of lever in a different form; the verge wire, 
which presses on the pendulum rod and keeps it going is 
the long arm of our lever, but instead of many there is only 
one. The short arm of our lever is the pallet, and there 
are two of these. Therefore we have a form of lever in 
which there is one long arm and two short ones ; but as the 
two are never acting at the same time they do not interfere 
with each other. 



TJIE MODERN CLOCK. 



Ol 



These systems of levers have another advantage, which 
is that one arrri need not be on the opposite side of the ful- 




ff 



Fii-. 25. 



crum from the other. It may be on the same side as in the 
verge or at any other convenient point. This enables us 
to save space in arranging our trains, as such a collection 



I02 THE MODERN CLOCK. 

of wheels and pinions is called, by placing them in any ,po- 
sition which, on account of other facts, may seem desirable. 

Peculiarities of Angular Motion. — Now our collec- 
tions of levers must move in certain directions in order to 
be serviceable and in order to describe these things prop- 
erly, we must have names for these movements so that we 
can convey our thoughts to each othei'. Let us see how 
they move. They will not move vertically (up or down) 
or horizontally (sidewise), because we have taken great 
pains to prevent them from doing so by confining the cen- 
tral bars of our levers in a fixed position by making pivots 
on their ends and fitting them carefully into pivot holes in 
the plates, so that they can move only in one plane, and 
that movement must be in a circular direction in that pre- 
determined plane. Consequently we must designate any 
movement in terms of the portions of a circle, because that 
is the only way they can move. 

These portions of a circle are called angles, which is a 
general term meaning always a portion of a circle, meas- 
ured from its center ; this will perhaps be plainer if we con- 
sider that whenever we want to be specific in mentioning 
any particular size of angle we must speak of it in degrees, 
minutes and seconds, which are the names of the standard 
parts into which a circle is divided. Now in every circle, 
large or small, there are 360 degrees, because a degree is 
I -360th part of a circle, and this measurement is always 
from its center. Consequently a degree, or any angle com- 
posed of a number of degrees, is always the same, because, 
being measured from its center, such measurements of any 
two circles will coincide as far as they go. If we draw 
two circles having their centers over each other at A, Fig. 
26, and take a tenth part of each, we shall have 36o°-^-io:= 
36°, which we shall mark out by drawing radial lines to 
the circumference of each circle, and we shall find this to 
be true: the radii of the smaller circle AB and AC will 



THE MODERN CLOCK. 



103 



coincide M^ith the radii AD and AE as far as they go. This 
is because each is the tenth part of its circle, measured from 
its center. Now that portion of the circumference of the 
circle BC will be smaller than the same portion DE of the 
larger circle, but each will be a tenth part of its ozvn circle, 
although they are not the same size when measured by a 
rule on the circumference. This is a point which has 
bothered so many people w^hen taking up the study of an- 
gular measurement that we have tried to make it absurdly 







clear. An angle never means so many feet, inches or 
millimeters ; it always means a portion of a circle, measured 
from the center. ^ v ,ji":^i 

There is one feature about these angular (of circular) 
measurements that is of great convenience, which is that 
as no definite size is mentioned, but only proportionate 
sizes, the description of the machine described need not be 
changed for any size desired, as it will fit all sizes. It thus 
becomes a flexible term, like the fraction ''one-half," chang- 
ing its size to suit the occasion. Thus, one-half of 300,000 
bushels of wheat is 150,000 bushels; one-half of 10 bush- 
els is 5 bushels ; one-half of one bushel is two pecks ; yet 
each is one-half. It is so with our angles. 

There are some other terms which we shall do well to 
investigate before we leave the subject of angular meas- 



I04 



THE MODERN CLOCK. 



urements, which are the relations between the straight and 
curved lines we shall need to study in our drawings of the 
various escapements. A radius (plural radii) is a straight 
line drawn from the center of a circle to its circumference. 
A tangent is a straight line drawn outside the circum- 
ference, touching (but not cutting) it at right angles (90 
degrees) to a radius drawn to the point of tangency (point 
where it touches the circumference). A general misun- 
derstanding of this term (tangent) has done much to hinder 
a proper comprehension of the writers who have attempted 
to make clear the mysteries of the escapements. Its im- 
portance will be seen when we recollect that about the first 
thing we do in laying out an escapement is to draw tangents 
to the pitch circle of the escape wheel and plant our pallet 
center where these tangents intersect on the line of cen- 
ters. They should always be drawn at right angles to the 
radii which mark the angles we choose for the working 
portion of our escape wheel. If properly drawn we shall 
find that the pallet arbor will then locate itself at the cor- 
rect distance from the escape wheel center for any desired 
angle of escapement. We shall also discover that it will 
take a different center distance for every different angle 
and yet each different position will be the correct one for 
its angle, Fig. 27. 

Because an angle is always the same, no matter how far 
from the center the radii defining it are carried, we are 
able to work conveniently with large drawing instruments 
on small drawings. Thus we can use an eight or ten inch 
protractor in laying off our angles, so as to get the degrees 
large enough to measure accurately, mark the degrees with 
dots on our paper and then draw our lines with a straight 
edge from the center towards the dots, as far as we wish 
to go. Thus we can lay off the angles on a one-inch 
escape wheel with a ten-inch protractor more easily and 
correctly than if we were using a smaller instrument. 



THE MODERN CLOCK. I05 







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Fig. 27, 



I06 THE MODERN CLOCK. 

Another thing which will help us in understanding these 
drawings is that the effective length of a lever is its dis- 
tance from the center to the working point, measured in 
a straight line. Thus in a pallet of a clock the distance 
of the pallets from the center of the pallet arbor is the 
effective length of that arm of the lever, no matter how 
it may be curved for ornament or for other reasons. 

The lines and circles drawn to enable us to take the 
necessary measurements of angles and center distances are 
called "'construction lines" and are generally dotted on 
the paper to enable us to distinguish them as lines for 
measurement only, while the lines which are intended to 
define the actual shapes of the pieces thus drawn are solid 
lines. By observing this distinction we are enabled to 
show the actual shapes of the objects and all their angular 
measurements clearly on the one drawing. 

With these explanations the student should be able to 
read clearly and correctly the many drawings which fol- 
low, and we will now turn our attention to the escape- 
ments. In doing this we shall meet with a constant use 
of certain terms which have a peculiar and special mean- 
ing when applied to escapements. 

The Lift is the amount of angular motion imparted to 
the verge or anchor by the teeth of the escape wheel press- 
ing against the pallets and pushing first one and then the 
other out of the way, so that the escape wheel teeth may 
pass. According as the angular motion is more or less 
the "Hft" is said to be greater or less; as this motion is 
circular, it must be expressed in degrees. The lifting 
planes are those surfaces which produce this motion; in 
clocks with pendulums the lifting planes are generally on 
the pallets, being those hard and smoothly polished sur- 
faces over which the points of the escape wheel teeth slide 
in escaping. In lever escapements the lifting planes are 
frequently on the escape wheel, the pallets being merely 



THE MODERN CLOCK. 



07 



round pins. Such an escape wheel is said to have club 
teeth, as distinguished from the pointed teeth used when 
the Hfting planes are on the pallets. In the cylinder 
escapement the lifting planes are on the escape wheel; 
they are curved instead of being straight; and there is but 
one pallet, which is on the lip of the cylinder. In the 
forms of lever escapement used in watches and some 
clocks the lift is divided, part of the lifting planes being 
also on the pallets; in this case both sets of planes are 
shorter than if they were entirely on one or the other, but 
they must be long enough so that combined they will pro- 
duce the requisite amount of angular motion of the pallets, 
so as to give the requisite impulse to the pendulum or bal- 
ance. 

The Drop is the amount of circular motion, measured 
in degrees, which the escape wheel has from the instant 
the tooth escapes from one pallet to that point at which it 
is stopped by the other pallet catching another tooth. Dur- 
ing this period the train is running down without impart- 
ing any power to the pendulum or balance, hence the drop 
is entirely lost motion. We must have it, however, as it 
requires some time for the other pallet to move far enough 
within the pitch circle of the escape wheel to safely catch 
and stop the next tooth under all circumstances. It is the 
freedom and safety of the working plan of our escape- 
ment, but it is advisable to keep the drop as small as is 
possible with safe locking. 

The Lock is also angular motion and is measured in 
degrees from the center of the pallet arbor. It is the 
distance which the pallet has moved inside of the pitch 
circle of the escape wheel before being struck by the escape 
wheel tooth. It is measured from the edge of the lifting 
plane to the point of the tooth where it rests on the lock- 
ing face of the pallet. A safe lock is necessary in order 



I08 THE MODERN CLOCK. 

to prevent the points of the escape wheel teeth butting 
against the lifting planes, stopping the clock and injuring 
the teeth. We want to point out that from the instant 
of escaping to the instant of locking we have the two parts 
of our escapement propelled by different and entirely sep- 
arate forces and moving at different speeds. The pallets, 
after having given impulse to the pendulum, are controlled 
by the pendulum and moved by it; in the case of a heavy 
pendulum ball at the end of a 40-inch lever, this control 
is very steady, powerful and quite slow. The escape 
wheel, the lightest and fastest in the train, is driven by 
the weight or spring and moves independently of the 
pallets during the drop, so that safe locking is important. 
It should never be too deep, as it would increase the swing 
of the pendulum too much; this is especially true with 
short and light pendulums and strong mainsprings. 

The Run. — After locking the pallet continues to move 
inward towards the escape wheel center as the pendulum 
continues its course, and the amount of this motion, meas- 
ured in degrees from the center of the pallet arbor, is 
called the run. 

When the escapement is properly adjusted the lifting 
planes are of the same length on both pallets, when they 
are measured in degrees of motion given to the pallet ar- 
bor. They may or may not be equal in length when 
measured by a rule on the faces of the pallets. There 
should also be an equal and safe lock on each pallet, as 
measured in degrees of movement of the pallet arbor. 
The run should also be equal. 

The reason why one lifting plane may be longer than 
the other and still give the same amount of lift is that 
some escapements are constructed with unequal lockings, 
so that one radius is longer than the other, and this, as 
we explained at length in treating of angles. Fig. 26, would 
make a difference in the length of arc traversed by the 
longer arm for the same angle of motion. 



CHAPTER VIII. 

THE GRAHAM OR DEAD BEAT ESCAPEMENT. 

This escapement is so called because the escape wheel 
remains "dead" (motionless) during the periods between 
the impulses given to the pendulum. It is the original or 
predecessor of the well known detached lever escapement 
so common in watches, and it is surprising how many 
watchmakers who are fairly well posted on the latter form 
exhibit a surprising ignorance of this escapement as used 
in clocks. It has like the latter a "lock," "lift" and "run" ; 
the only difference being that it has no "draw," the control 
by the verge wire rendering the draw unnecessary. 

It may be made to embrace any number of teeth of the 
escape wheel, but, owing to the peculiarities of angular 
motion referred to in the last chapter, see Fig. 26, B C, D E, 
the increased arcs traveled as the pallet arms lengthen in- 
troduce elements of friction which counterbalance and in 
some cases exceed the advantage gained by increasing the 
length of the lever used to propel the pendulum. Similarly, 
the too short armed escapements were found to cause in- 
creased difficulty from faulty fitting of the pivots and their 
holes, and other errors of workmanship, which errors could 
not be reduced in the same proportion as the arms were 
shortened, so that it has been determined by practice that a 
pallet embracing ninety degrees, or one-fourth of the cir- 
cumference of the escape wheel, offers perhaps the best 
escapement of this nature that can be made. Therefore the 
factories generally now make them in this way. But as 
many clocks are coming in for repair with greater or less 
5ircs of escapement and the repairers must fix them satis- 

109 



no THE MODERN CLOCK. 

factorily, we will begin at the beginning by explaining how 
to make the escapement of any angle whatever, from one 
tooth up to 140 degrees, or nearly half of the escape wheel. 

It is quite a common thing for some workmen to imagine 
that in making an escapement, the pallets ought to take 
in a given number of teeth, and that the number which they 
suppose to be right must not be departed from; but there 
seems to be no rule that necessarily prescribes any number 
of teeth to be used arbitrarily. The nearer that the center of 
motion of the pallets is to the center of the escape wheel, the 
less will be the number of teeth that will be embraced by the 
pallets. Fig. 28 is an illustration of the distances between 
the center of motion of the pallets and the center of the 
wheel required for 3, 5, 7, 9 and 11 teeth in a wheel of the 
same size as the circle; but although we have adopted 
these numbers so as to make a symmetrical diagram, any 
other numbers that may be desirable can be used with equal 
propriety. All that is necessary to be done to find the 
proper center of motion of the pallets is first to determine 
the number of teeth that are to be embraced, and draw 
lines (radii) from the points of the outside ones of the 
number to the center of the wheel, and at right angles to 
these lines draw other two lines (tangents), and the point 
where they intersect each other on the line of centers will be 
the center of motion of the pallets. 

It will be seen by the diagram. Fig. 28, that by this 
method the distance between the centers of motion of the 
pallets and that of the scape-wheel takes care of itself for a 
given number of teeth and that it is greater when eleven 
and one-half teeth are to be embraced than for eight or for 
a less number. These short pallet arms are imagined by 
some workmen to be objectionable, on the supposition that 
it will take a heavier weight to drive the clock; but it can 
easily be shown that this objection is altogether imaginary. 
Now, bearing in mind the principles of leverage, if the dis- 
tance between the pallets and escape wheel centers is very 



THE MODERN CLOCK. 



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112 THE MODERN CLOCK. 

long, as in Graham's plan, in which the pallets embraced 
138° of the escape wheel, the value of the impulse received 
from the scape-wheel and communicated through the pallets 
to the pendulum is no doubt greater with a proper length of 
verge wire, for, the lifting planes being longer, the leverage 
is applied to the pendulum for a longer arc of its vibration, 
yet we must not suppose that from this fact the clock will go 




A 

Fig. 29. Note the diflference ia length of arc for the same angle. 

with less weight, for it is easy to see that the longer the 
pallet-arms are the greater will be the distance the teeth 
of the escape wheel will have to move (run) on the circular 
part of the pallets. See Fig. 29. The extra amount of 
friction, and the consequent extra amount of resistance 
offered to the pendulum, caused by the extra distance the 
points of the teeth run on the circular locking planes of the 
pallets and back again, destroys all the value of the extra 
amount of impulse given to the pendulum in the first in- 
stance by means of the long arms of the pallets. The escape 
wheel tooth restinjy on the locking plane of the pallet is quite 
var-able in its effective action, and since it rests on the 
pallet during a part of each swing of the pendulum and the 
pendulum is called on to move the pallet back and forth 
under the tooth, any change in the- friction between the tooth 
and pallet is felt by the pendulum and when the clock gets 



THE MODERN CLOCK. II3 

dirty and the friction between the tooth and pallet is in- 
creased, the rate of the clock gets slow, as the friction holds 
the pendulum from moving as fast as it would without 
friction. Now, as this friction increases by dirt and thick- 
ening of the oil, all these forms of escapements are subject 
to changes and so change the clock's rate. An increase of 
the driving weight, or force of the mainspring, of clocks 
with dead-beat escapements always tends to make their rate 
slow, from the action mentioned. 

It is for this reason that moderately short arms are used 
in clocks having dead-beat escapements of modern con- 
struction. Most of the first-class modern makeri of astro- 
nomical clocks only embrace seven and one-half tectli, en a 
30-tooth wheel, with the centers of motion of the pallets and 
scape-wheel proportionately nearer, as it can be mathe- 
maticallv demonstrated that with the pallets embracing an 
arc of 90° the application of the power to the pendulum is at 
right angles to the rod and therefore is most effective. 

To Draw the Escapement. — In order to make the mat- 
ter clearer we show in Fig. 30 the successive stages of 
drawing an escapement and also the completed work in 
Figs. 32 and 33 embracing different numbers of teeth. Draw 
a line, A B, Fig. 30, to serve as a basis for measurements. 
With a compass draw from some point C on this line a 
circle to represent the diameter of our escape wheel. Now 
we shall require to know how many teeth there will be in 
our escape wheel. There may be 60, 40, 33, 32, 30, or any 
other number we desire to give it ; seconds pendulums gen- 
erally have 30 teeth in this wheel, because this allows the 
second hand to be mounted directly on the escape wheel 
arbor and thus avoids complications. We divide the number 
of degrees in a circle (360) by the number of teeth we have 
selected, say 30. 360 -f- 30 = 12° for each tooth and space. 
One-fourth of 360° equals 90° and one-fourth of 30 teeth 
equals seven and one-half teeth ; each tooth equaling 12 



"4 



THE MODERN CLOCKo 



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Fig. 30, 



THE MODERN CI>OCK. II5 

degrees, we have 12 X 7 = 84°> which gives us six degrees 
for drop, to ensure the safety of our actions. 

We now take 90° and, dividing it, set off 45° each side of 
our center line and draw radii, R, from the center to the cir- 
cumference of our circle ; this marks the beginnings of our 
pallets. Now to find our pallet center distance we draw 
tangents, T (at right angles), from the ends of these radii 
toward the line of centers. The point where they intersect 
on the line of centers is the pallet center. 

Now we must determine how much motion we are going 
to give our pendulum, so that we can give the proper lift to 
our pallets. Four degrees of swing is usual for a seconds 
pendulum, so we will take four degrees and, dividing it, give 
two degrees of lift to each pallet. To do this we draw a line 
two degrees inside the tangent, T (towards the escape wheel 
center), from our pallet center on the entering pallet side 
and another line from the pallet center two degrees outside 
of the tangent, T, on the exit pallet side. Next, from the 
pallet center we draw arcs of circles cutting the tangents, 
T, and the radii, R, where they intersect; this gives us the 
locking planes on which the teeth of the escape wheel "run" 
(slide) during the excursions of the pendulum, if the 
escapement is to have unequal lockings ; if the lockings are 
to be equidistant (if the pallet arms are to be of equal length) 
the arc for the entering pallet is drawn three degrees below 
(outside) the radius, R, while that on the exit pallet is 
drawn three degrees above (inside) the exit radius. Finally 
the lifting planes are drawn from the intersection of the arcs 
of circles struck from the pallet center with their tangents, 
T, to the lines, marking the limits of the lift, two degrees 
away. These lifting planes should be at an angle of 60° 
from the radii, R, and as a tangent is always at right angles 
(90°) to its radius, they are consequently at 30° to 
the tangents running to the pallet center. Thus we can 
measure these angles from either the escape wheel or the 
pallet center, as may be most convenient. 



Il6 THE MODERN CLOCK. 

When making a new pallet fork, it is most convenient to 
mark out the lifting planes on the steel at 30° from the 
tangents, T, as we then do not have to bother with the 
escape wheel further than to get its center distance and the 
degrees of arc the lifting planes are to embrace. The work- 
man who is not familiar with this rule is apt to have his 
ideas upset at first by the angles of inclination toward the 
center line which the lifting planes will take for different 
center distances, as owing to the fact that the tangents meet 
on the center line at different angles for different distances, 
the lifting planes assume different positions with regard to 
the center line and he may think that they do not "look 



06.'P''''T'-^^>P:<> 



Fig. 31. 



right." They are right, however, when drawn at 30° to 
their tangents. Fig. 31 shows several pallets with different 
arcs arranged in line for purposes of comparison, each being 
drawn according to the above rule, as measurements with a 
protractor will show. 

We have now arrived at the complete escapement, having 
finished our pallets. We have, however, nothing to hold 
them in position ; they must be rigidly held in position with 
regard to each other and the escape wheel, consequently we 
will make a yoke to connect them to the pallet arbor out of 
the same steel, giving it any desired shape that will not inter- 
fere with the working of the clock. Two of the most usual 
forms are shown at Figs. 32 and 33. 



THE MODERN CLOCK. 




Fig. 32. 



ii8 



THE MODERN CLOCK. 




Fig. 33. 



THE MODERN CLOCK. II9 

Let us see how this rule will work in repairs. Suppose 
we have a clock brought in with the pallet fork missing, 
and that the movement is one of those in which the pallet 
arbor is held by adjustable cocks which have been misplaced 
or lost, so that we don't know the center distance of the 
pallet arbor and escape wheel. We shall have to make a 
new part. 

Measure the escape wheel, getting its diameter carefully, 
take half of this as a radius, and mark out the circle with a 
fine needle point on some copper, brass or sheet steel, draw- 
ing the escapement as detailed in Figs. 30 and 32. Then 
measure carefully the angles made by the tangents with the 
center line ; take the steel which is to be used in making the 
pallets and fork ; draw on it a center line ; lay off the 
tangents and the lift lines ; draw the locking arcs and the 
lifting planes carefully from the tangents and give the rest 
of the fork a symmetrical shape. Use needle points to draw 
with and have your protractor large enough to measure 
your angles accurately. Then drill or saw out and file to 
your lines, except on the locking and lifting planes ; leave 
these large enough to stand grinding or polishing after 
hardening. Harden ; draw to a straw color and polish the 
planes. Your verge will fit if it has not warped in harden- 
ing. If this is the case, soften the center, keeping the heat 
away from the pallets, and bend or twist the arms until 
the verge will fit the drawing, when laid on top of it. In 
grinding the pallets the fork should be mounted on its arbor 
and the latter held between the centers of a rounding up 
tool while the grinding is done by a lap in the lathe. This 
insures that the planes will be parallel to the pallet arbor 
and hence square with the escape wheel teeth, so that they 
will not create an end thrust on either escape or pallet 
arbor. It is also the quickest, easiest and most reliable way 
of doing the job. When clocks come in with the pallets 
badly cut ; soften the center of the fork, place the ends be- 
tween the jaws of a vise, squeeze enough to bring them 



I20 



THE MODERN CLOCK. 









Fig. 34. Drawing escape wheel to fit a tracing from a pallet fork. 



THE MODERN CLOCK. 121 

closer, mount in the rounding up tool and lap off the cut 
planes until they are smooth and stand at the proper angle ; 
then polish. This is done quickly. 

Can we work the rule backwards? Suppose we get a 
clock in which we have the pallet arbor adjustable as before, 
and we have the pallet fork all in good shape, but we have 
lost the escape wheel, or it has been butchered by somebody 
before coming to us, so that a new one is required. 

Take off the pallet fork; lay it on a sheet of brass and 
trace around it carefully with a needle point, Fig. 34. 
Mark the center carefully at the pallet arbor hole and meas- 
ure carefully the distance between the pallets and mark that 
center. Draw a center line cutting these centers and ex- 
tending beyond. Now draw the tangent from the beginning 
of the entering pallet (as shown by the tracing on our 
brass), to the pallet center; do the same with the exit pallet. 
Now take a metal square and place it on one of the tangents 
exactly, with the end at the beginning of the entering pallet ; 
trace a line cutting the line of centers and we have the radius 
of our escape wheel. Trace a circle from the intersection of 
the radius and the center line and we have the circumference 
of our escape wheel. This circle should also cut the inter- 
section of the tangent and radius on the other side if it is 
drawn correctly; if it does not do this an error has been 
made in the drawing. 

Having found the diameter and circumference of our 
escape wheel it may be sawed out and mounted for wheel 
cutting; or, if we have no wheel cutter and must make 
the wheel, we must draw it on the brass by hand with a fine 
needle point before proceeding to saw it out by hand, Fig. 
35. Say that the wheel is to have thirty-two teeth, which 
is a common number ; then 360° -^ 32 ^ ii^° as the space 
between the points of our teeth. Take a large protractor, 
one with the degrees large enough to be divided (I use a 
ten-inch) ; place its center on the center of our escape wheel, 
set off ii^° and mark them on the brass with the needle 



122 



THE MODERN CLOCK. 




Fig. 35. Drawing an escape wheel to cut. The last drawing shows the 
complete wheel. 



THE MODERN CLOCK. I23 

point, at the edge of the protractor. Then take a straight 
edge and draw a radius from the center to the circumfer- 
ence ; change the straight edge to the other mark and mark 
the point where it crosses the circumference; set your 
dividers accurately by this mark and space off the teeth on 
your circumference. If they are set at eleven degrees and 
fifteen minutes they will come out exactly at the end. Now 
take your protractor and with its center at the junction of 
the radius and circumference set off ten degrees and draw 
a line past the center of the wheel ; set off twenty degrees 
and draw another line the same way. From the center of the 
escape wheel draw two circles just touching these lines. 
Outside of these draw two circles defining the inner and 
outer edges of the rim of the wheel. With the straight edge 
just touching the inner circle draw in the fronts of the teeth ; 
these will all be set at ten degrees from a radius, so that 
only the extreme points will touch the locking planes of 
the pallets and thus reduce the friction during the run. The 
backs of the teeth are marked out in the same way from 
the twenty-degree circle. The hub is made to coincide with 
the ten-degree circle; the spokes are traced in and we are 
ready to begin sawing out. 

If the workman has a wheel cutter the job is much 
simpler. A piece of brass is mounted on a cement brass 
with soft solder, faced off, centered and the pitch circle, 
inner and outer edges of the rim and the hub are traced with 
the T-rest and graver. The extra metal is then cut away 
and a suitable index placed on the spindle and locked. The 
wheel cutter is set up with a fine toothed, smooth cutting 
saw on the spindle, horizontal, with its upper edge at the 
line of centers of the lathe. It is then run out to the cir- 
cumference of the wheel, turned upwards ten degrees and 
the wheel cut around. Fig. 36. This makes the fronts of the 
teeth. Turn the saw ten degrees more and cut the backs 
of the teeth. Then turn the saw so that it will reach from 
the front of one tooth to the root of the back of the next 



124 "^^^ MODERN CLOCK. 




Fig. 36. Making an escape wheel with a saw, showing the successive 

cuts. 



THE MODERN CLOCK. 1 25 

one, without touching either tooth, and cut round again; 
this cuts out a triangular piece of waste metal between the 
teeth. Turn the saw again so that it reaches from the bot- 
tom of the front of a tooth to the top of the back of the next 
one and cut around again, thus removing another portion 
of the waste metal, and leaving only a small triangle be- 
tween the teeth. Lower the saw its own thickness and cut 
around the wheel again, repeating the operation until the 
waste metal is all removed and you have a smooth circular 
rim between the teeth. Fig. 36. 

Set the saw horizontally at the lathe center ; raise it one- 
half the thickness of the spokes; set the index pin of the 
lathe head firmly at O ; feed in the saw the thickness of the 
wheel and make straight cuts across from the circle of the 
inner rim to the circle marking the hub, but not cutting 
either ; set the index pin at 30 and repeat ; next lower your 
saw and cut the other side of the spokes the same way. 

Next you can mount a lap in place of the saw and smooth 
the fronts and backs of the teeth and if you have a rather 
thick disc the outer edge of the rim, between the teeth, 
may also be smoothed. 

If you have a good strong pivot polisher, mount a tri- 
angular end mill in the spindle, lock the yoke, and cut the 
arcs of circles of the hub and rim from edge to edge of 
the spokes, feeding carefully against the mill with the hand 
on the lathe pulley. 

Put on your jeweling tailstock and open the wheel to fit 
the pinion, collet, or arbor, if there is no collet. 

You now have the wheel all done, except facing the side 
that was soldered to the cement brass and trimming up the 
corners of the spokes at the rim and hub, and 3^ou have got 
it round, true and correct in much less time than you could 
have done in any other way, while an immense amount of 
work with the file and eye-glass has been avoided. It is 
true because it was soldered in position at the beginning and 
has not been removed until finished. 



126 THK MODERN CLOCK 

Sometimes what are known from their appearance as 
club-shaped teeth are used in the wheels of Graham's 
escapements. Pendulums receive their impulse from escape- 
ments made in this manner partly from the lifting planes on 
-the pallets, and partly from the planes on the scape- wheel. 
The advantage gained by this method is, that wheels made 
in this way will work with the least possible drop, and con- 
sequently, power is saved; but the power saved is thrown 
away again in the increased friction of the planes of the 
wheel against those of the pallets, which is considerably 
more than when plain-pointed teeth are used on the escape 
wheel. 

Clock pallets are usually made of steel, and on the finer 
classes of work jewels are often set into them to prevent the 
oil from drying, after the same fashion as jewels are placed 
in steel pallets in a lever watch ; but it is obvious that stone 
pallets made in this way have to be finished with polishers 
held in the hand, and that, except in factories, they cannot 
he made so perfectly regular, especially that pallet that is 
struck downwards, as the particular action of a fine Graham 
escapement requires. When great accuracy is required, the 
pallets are usually made of separate pieces, and the acting 
circles ground and polished on laps, running in a lathe. 
This method of constructing pallets also allows a means of 
adjustment which in some particular instances is very con- 
venient. 

There is also a plan of making jeweled pallets adjustable, 
which is practiced on fine work, such as astronomical and 
master clocks. The pallet fork consists of two pieces of 
thin, hard, sheet brass, cut out in the usual form and two 
mounted on one arbor. Circular grooves are cut in the 
p^des of both plates, at the proper distance, and of the 
proper size t-o receive the jewels which are the acting parte 
of the pallets. When jewels cannot be made of the desired 
size, pallets of steel are made, and the jewels are then set 
into the steel Ictrge enough for the teeth of the wheel to act 



THE MODERN CLOCK, 



127 



o 




Fig. 37. Brocot's visible escapement, escaping over 120* with pointed 
teeth. Dotted lines on pallets show where they are cut to avoid 
stopping. 



128 THE MODERN CLOCK. 

Upon. The two parts of the fork are fastened at a given 
distance apart, and the jewels, or pieces of steel, go in be- 
tween them, and, after they have been adjusted to the proper 
position, are fastened by screws that pull the frames close 
together and press against the edges of the jewels. Pallets 
made in this manner have a very elegant appearance. An- 
other method is to have only one frame, and to have it thick 
enough, where the jewels have to be set in, to allow a groove 
to be cut in its side as deep as the jewels (or the pieces of 
steel that hold the jewels) are broad, and which are held in 
their proper position by screws. This system of jeweling 
pallets is frequently adopted by the makers of fine mantel 
clocks. 

Brocoi's Visible Escapement. — Fig. ^y represents a 
system of making and jeweling pallets much used by the 
French in their small work, especially in visible escapements. 
The acting parts of the pallets are simply cylinders, gener- 
ally of colored stones, usually garnets, one-half of each 
cylinder being cut away. These cylinders extend some dis- 
tance from the front of the pallet frame, and work into the 
escape wheel the same as the pallets of a Graham escape- 
ment — the round parts of the pallets serving as impulse 
planes. The neck of the brass pallet frame is cut up in the 
center, and the width between the pallets is sometimes ad- 
justed by a screw, sometimes by bending the arms. 

Clock movements with this escapement, of a careful con- 
struction, will frequently come for repairs, accompanied by 
the complaint of constant stopping and that no attempt at 
closely regulating can succeed with them, although they 
appear to have no visible disturbing cause. In such cases 
the depthing of the escapement is generally wrong. With 
proper depthing the point of the escape wheel tooth should 
drop on the center or a little beyond the center of the pallet 
stone. If it is set in this way the clock will stop when 
wound, especially if it has a strong spring, as the light 



THE MODERN CLOCK. 



129 




Fig. 38. Brocot's visible escapement escaping over 90° with a small lift 
on the escape wheel teeth. 



130 THE MODERN CLOCK. 

pendulum will not then have momentum enough to unlock 
it against the full power of the spring. If the pallets are set 
shallow, in order to avoid this difficulty, then, the pendulum 
will take too short a swing and thus the clock will have a 
gaining rate. Generally the pendulum ball cannot be made 
enough heavier to correct the defect. 

In these movements, in which the length of the pendulum 
does not exceed 4 inches, the pallet fork embraces, generally 
about 120°, or the one-third part of the wheel; it will be 
seen that unless there are stop works on the barrel of the 
main spring no manner of regulating is possible with these 
conditions, in view of the considerable influence exercised 
by the mainspring through the train on the very light pendu- 
lum, and by replacing this unduly high anchor by a lower 
one, I have always been able to produce a very satisfactory 
rate with movements having pendulums of three and a half 
to four inches. Fig. 38 shows a 90° escapement with a 
small lift on the escape wheel teeth. 

In spite of its incontestable qualities, the visible escape- 
ment possesses one inherent fault. I refer to the formation 
of its pallets, the semi-circular shape of which renders 
unequal the action of the train in giving impulse to the 
pendulum exceeding 50 centimeters (20 inches), since to 
make it to describe arcs of from one to two degrees only, 
with pendulums of from 60 centimeters to one meter in 
length, it became necessary to make the anchor arms ex- 
tremely long, which considerably impeded the freedom of 
action, especially when the oil became thick, and this dis- 
position would, therefore, stand in direct contradiction with 
the principles of modern horology. Both stopping and 
the irregularity of rate can be obviated by changing the 
semi-circular form of the pallets for one of an inclinea 
plane, either by grinding a new plane or turning the stones 
in such manner as to offer an inclined plane to the action 
of the wheel, analagous to that of the Graham escapement. 



THE MODERN CLOCK. I3I 

See Fig. 37, the dotted lines on the pallets showing the 
portion to be ground away. 

The importance of this transformation will readily be 
understood ; it suffices to give to these planes a more or less 
large inclination in order to obtain a greater regularity of 
lifting, and, at desire, a lifting arc more or less considerable 
without being compelled to modify the proportions of the 
fork or to exaggerate the center distance of wheel and 
pallet arbor. 

In adjusting an escapement, perhaps it may be advisable 
to mention that moving the pallets closer together, or open- 
ing them wider, will only adjust the drop on one side, while 
the other drop can only be affected by altering the distance 
between the centers of the pallets and scape-wheel. This is 
accomplished in various ways. The French method con- 
sists of an eccentric bush, riveted in the frame just tight 
enough to be turned by a screw-driver. Another plan, com- 
mon in America, is simply pieces of brass (cocks) fastened 
on the sides of the frames. The pivots of the pallet axis are 
hung. in holes in these cocks, and an adjustment of great 
accuracy may be quickly obtained by loosening the clamping 
screws. Lock, drop and run should be of the same amount 
on each pallet. However, we do not approve of adjustments 
of any kind, except in the very highest class of clocks, 
where they ai^ always likely to be under the care of skillful 
people, who understand how to use the adjustments to obtain 
nicety of action in the various parts. 

In making escapements, lightness of all the parts ought 
to be an object always in view in the mind of the workman, 
and such materials should be used as will best serve that 
purpose. The scape-wheel, and the pallets and fork, should 
have no more metal in them than is necessary for stiffness. 
The pallet arbor, and also the escape-wheel arbor, should 
be left pretty thick when the wheel and pallets are placed 
in the center between the plates, to prevent their springing 
when giving impulse to the pendulum. We have often been 



132 THE MODERN CLOCK. 

puzzled to find out the necessity or the utihty of placing 
them in the center between the plates, as they are so gener- 
ally done in English clockwork. The escapement acts much 
more firmly when it is placed near one of the plates, and it 
is just as easy to make it in this way as in the other. 

It is often assumed that the friction of the teeth on the 
circular part of the pallets of a dead-beat escapement is 
small in amount and unimportant in its value. With re- 
spect to its amount, we believe it is often not far short of 
being equal to one-half of the combined retarding forces 
presented to the pendulum; and with respect to its being 
unimportant, this assumption is founded on the supposition 
that it is always a uniform force, when it is easy to show 
that it is not a uniform force. It is very well known that the 
force transmitted in clock trains, from each wheel to the 
next, is very far from being constant. Small defects in the 
forms of the teeth of the wheels and of the leaves of the 
pinions, and also in the depths to which they are set into 
each other, cause irregularities in the amount of power 
transmitted from each wheel to the next ; and the accidental 
combination of these irregularities in a train of four or five 
wheels, makes the force transmitted from the first to the last 
exceedingly variable. The wearing of the parts and the 
change in the state of the oil, are causes of further irregu- 
larities ; and, from these causes, it must be admitted that the 
propelling power of the scape-wheel on the pallets is of a 
variable amount, and a more important question for consid- 
eration than it is usually supposed to be. To avoid the con- 
sequences of this irregular pressure of the scape-wheel on 
the pallets being communicated to the pendulum, is a prob- 
lem that has puzzled skillful mechanicians for many years ; 
for, although we find the Graham escapement to be pro- 
nounced both theoretically and mechanically correct, and 
by some authorities little short of perfection, we find some of 
these same authorities — both theoretically and practically — 
testify their dissatisfaction with it by endeavoring to im- 



THE MODERN CLOCK. 



33 



prove on it. In Europe the experience of generations and 
the expenditure of small fortunes, in pursuit of this im- 
provement, through the agency of the gravity, and other 
::orms of escapements, proves this fact ; while of late years, 
in the United States, much time and money has been spent 
on the same subject, and results have been reached which 
have raised questions that ten years ago were little dreamed 
of by those clockmakers who are generally engaged on the 
highest class of work. 

While considering this class of escapements, we would 
say a few words in regard to the sizes of escape wheels 
generally used. Small wheels can now be cut as accurately 
as larger ones and there is now no reason or necessity for 
continuing the use of a wheel of the size Graham and 
Le Paute used, and which has been the size generally 
adopted by most European makers who use these escape- 
ments. The Germans and Swiss make wheels much smaller 
for Graham escapements than the English makers do ; and 
the American factories make them smaller still. On the 
continent of Europe the wheels of Le Paute's escapement 
are made much larger than they are made in England and 
in the United States. No wheel, and more especially a 
scape-wheel, should be larger than will just give sufficient 
strength for the number of teeth it has to contain, in pro- 
portion to the amount of work that it has to perform. The 
amount of work a scape-wheel has to perform in giving mo- 
tion to the pendulum is of the lightest description, and not 
more than one-tenth of what it is popularly supposed to 
be, which is shown by its variation under slight increase of 
friction ; therefore we do not consider that we take extreme 
ground in recommending wheels for these escapements to be 
made nearly half the size their originators made them, and 
the pallets drawn off in proportion to the reduced size of 
the wheel. It is plain that by reducing the size of the wheel 
its inertia will be reduced. When the teeth begin to act 
on the inclined planes of the pallets, the wheel will be set in 



134 



THE MODERN CLOCK. 



motion with greater ease, as it has a shorter leverage, and 
the amount of the dead friction of the scape-wheel teeth on 
the inclined planes and circular part of the pallets will also 
be proportionately reduced by making the wheel smaller. 
Factory experience and examination of a large number of 
clocks in repair shops have also shown that smaller and 
thicker escape .wheels will wear much longer than larger 
and thinner ones, as all the wear is at the points of the 
teeth and this is the portion to be protected. 



CHAPTER IX. 

LE PAUTE's pin wheel ESCAPEMENT. 

Probably in no other escapement, except the lever, has 
there been so many modifications as in the pin wheel ; this 
is so to such an extent that it will be found by the student 
that nearly every escapement of this kind which he will 
examine will differ from its fellows if it has been made by 
a different maker. They will be found to vary in the lengths 
of the pallet arms from three-fourths to one and a half times 
the diameter of the escape wheel; some of them will have 
the longer arm of the pallets outside and some inside; some 
will have the lift for both pallets laid out on one side of the 
perpendicular P, Fig. 39, while others will have the lift 
divided, with the perpendicular in the center. Very old 
escapements have the pallet center directly over the escape 
wheel center, while the pallet arms work at an angle of 45°, 
while others have them with the pallet center planted on a 
perpendicular, tangent to the pitch line of the escape wheel. 
Some have the circular rest or locking faces of the pallets 
rounded slightly to hold the oil in position while others have 
them flat and still others have them made of hard stone, pol- 
ished. More than half have the pins in the escape wheel cut 
away for one-half of their diameters, leaving the bottoms 
Vound, as shown in Fig. 39, while others use a wider pin and 
trim away the bottoms also, as in Fig. 40, leaving the lifting 
surface on the pins not more than one-fourth the arc of the 
circle. This is especially true of the larger escapements 
used in tower clocks, though they are also found in regu- 
lators. 

In view of the wide variation in practice, therefore, we 
have endeavored to present in Fig. 39 a conservative state- 

135 



36 



TJIE MODERN CI.OCK. 



ment of the general practice as found in existing clocks. We 
say existing, because very few of these escapements are 
made now — none at all in America — and those in use are 




Fig. 39. Pin Wheel Escapement. 



generally in imported regulators, which have come from 
Switzerland or Germany. The Waterbury Clock Co. at 
one time made this escapement for its regulators and the 



THE MODERN CLOCK. 



137 



Seth Thomas Clock Company made a number of its early 
tower clocks with it, but both have discontinued it for some 
years, and it is safe to say that any movement coming into 




Fig. 40. Pin Wheel With Flattened Teeth. 



the watchmaker's hands which has this escapement is im- 
ported; or if American, it is out of the market. 

Le Paute claimed as an advantage the fact that the im- 
pact of the escape wheel teeth is downward on both pallets, 
whereas in the gravity and recoil escapements one blow is 
struck upwards and the other downwards. He claimed that 



138 THE MODERN CLOCK. 

by this means a better action was secured after the pivot 
holes began to wear, as there was less lost motion with both 
blows in the same direction and any shake would not affect 
the amount of impulse given to the pendulum. The differ- 
ence is more theoretical than practical, however, and the 
escapement possesses one serious fault, which is that the 
pins forming! the escape wheel teeth conduct the oil away 
from thC; palliets, so that the clock changes its rate in from 
eight months H;o one year after being oiled and cleaned. The 
most effective means of counteracting this is to round the 
locking planes of the pallets slightly, so that the oil will be 
held on them by capillary attraction. Another method is 
to turn the pins so that they are thicker in diameter at the 
point of contact with the pallets, but this is seldom tried. 
The best plan is to keep the pallets as close as they can be 
to the face of the wheel without touching. 

To Draw the Escapement. — In laying out this escape- 
ment the first thing to consider is the arc of swing of the 
pendulum, because one-half of the lift is on the pin and 
consequently one-half the lift must equal one-half the diam- 
eter of the pin, as shown in Fig. 39. If the pendulum swings 
four degrees, then the diameter of each pin must equal four 
degrees of the pallet movement. This establishes the size of 
our pin ; it is measured from the pallet staff hole. There are 
30 of these pins for a second's pendulum, and unless it is a 
very large escapement the pins cannot be made less in di- 
ameter than one-fourth the distance between the pins, or 
they will be too weak and will spring; consequently 
360-4-30=12° and i2°-^4=3°, so that three degrees of 
the pitch line of the escape wheel equals the swing of the 
pallet fork. This establishes the relation as to size between 
the escape wheel and the opening, or swing of the pallet 
fork. Draw a perpendicular, P, from the pallet center and 
on one side of it lay out the lift lines L, L; draw a line at 
right angles to the perpendicular and where it crosses the 



THE MODERN CLOCK. 



39 



inner lift line draw a circle touching the outer lift line. The 
diameter of this circle equals three degrees of the circum- 
ference of the wheel, on its pitch line, and .this multiplied by 
120 gives 360° or the pitch circumference of the escape 
wheel. Dividing the sum so found by 3. 141 5 gives the di- 
ameter of the escape wheel and half of this is the radius. 
After finding the radius draw the pitch circle and set out 
the other twenty-nine teeth spaced twelve degrees apart, and 
drawn in half circles as shown in Fig. 39. 

Now to get the thickness of the pallet arms. When the 
pin shown in action in Fig. 39 has just cleared the lower 
edge of the inner pallet, the succeeding pin should fall safely 
on the upper corner of the outer pallet; consequently the 
thickness of these two arms, the pin between them, and the 
drop (clearance between the pin and the lower edge of the 
upper pallet) should just equal the distance between two 
pins, from center to center, or 12° of the escape wheel. 
With the first or inner lift line as a starting point, draw the 
lower arcs of the pallets and draw the upper or locking 
planes from the perpendicular and the outer lift line. Then 
draw the lifting planes of the pallets by connecting the ends 
of these arcs. The enlarged view above the escape wheel 
in Fig. 39 will show how this is done more clearly than the 
main drawing. 

It is best to make the pallet fork of steel, in two pieces, 
screwed to a collet on the pallet arbor, as the inner arm must 
be bent, or offset, so that it will clear the pins of the escape 
wheel, and the pallets should lie in the same plane, as close 
to the wheel as is possible without touching it. The pallets 
are hardened. 

In tower clocks the escapement is so large that a pin 
having a diameter of three degrees of the escape wheel gives 
a half pin of greater strength than is necessary for the 
work to be done and such pins are cut away on the bottom, 
as in Fig. 40. In making the wheel it should be drilled in 
the lathe with the proper index to divide the wheel and the 



140 THE MODERN CLOCK. 

pins riveted in; then the pins are cut with a wheel cutter 
as if they were teeth of a wheel. Pins should be of hard 
brass. 

Care should be used in handling clocks with this escape- 
ment while the pendulum is connected with the pallet fork, 
as, if the motion of the fork should be reversed while a pin 
was on one of the lifting planes, it would bend or break the 
pin. 



CHAPTER X. 

THE RECOIL OR ANCHOR ESCAPEMENT. 

This escapement, always a favorite with clockmakers, 
has had a long and interesting history and development. 
Because it started with a suddenly achieved reputation, and 
because it is adapted to obtain fair results with the cheapest 
and consequently most unfavorable working conditions, it 
has won its way into almost universal use in the cheaper 
classes of clock work; that is to say, it is used in about 
ninety per cent of the pendulum clocks which are manu- 
factured to-day. 

It achieved a sudden reputation at its birth, because it 
was designed to replace the old verge, which, with its ninety 
degree pallets close to the arbor, and working into the 
crown wheel, required a very large swing of the pendulum. 
This necessitated a light ball, a short rod, required a great 
force to drive it, and made it impossible to do away with 
the circular error, while leaving the clock sensitive to vari- 
ations in power. The recoil escapement was therefore the 
first considerable advance in accuracy, as its use involved 
a longer and heavier pendulum, shorter arcs of vibration 
and less motive power than was practicable with the verge ; 
and as the pendulum was less controlled by the escapement, 
it was less influenced by variations of power. 

In the early escapements the entrance pallet was convex 
and the exit pallet concave. Escapements of this description 
may still be met with among the antiquities that occasionally 
drift into the repair shop. Later on both pallets were made 
straight, as shown in Fig. 41. It will be seen by studying 
the direction of the forces that the effect is to wear off the 

141 



142 



THE MODERN CLOCK. 



points of the teeth very rapidly, and for this reason the 
pallets were both made convex (See Fig. 42), so as to bring 
the rubbing action of the recoil more on the sides of the 




Fig. 41. Recoil Escapement with Straight Lifting Planes. 



teeth and do away to a large extent with the butting on the 
points which destroyed them so rapidly. 

The rather empirical methods of laying out the recoil 
escapement, which have gained general circulation in works 
on horology, have had much to do with bad depthings of 



THE MODERN CLOCK. I43 

.this escapement and the consequent undue wear of the 
escape wheel teeth and great variation in time keeping of 
the movements in which such faulty depthings occur, par- 
ticularly in eight-day movements with short and light pen- 
dulums. The escapement will invariably drive the clock 
faster for an increase of power and slower for a decrease ; 
an unduly great depthing will greatly increase the arc of 
vibration of the pendulum, as the train exerts pressure on 
the pendulum for a longer period during the vibration ; the 
consequence is that instead of the pendulum being as highly 
detached as possible, we have the opposite state of affairs 
and a combination of a strong spring, light pendulum and 
excessive depthing will easily make a variation of five min- 
utes a week in an eight-day clock. 

The generally accepted method of laying out this escape- 
ment is shown in Figs. 41 and 42, as follows : "Draw a 
circle representing the escape wheel ; multiply the radius of 
the escape wheel by 1.4 and set off this as the center dis- 
tance between the pallet and escape wheel centers. From 
the pallet staff center describe a circle with a radius equal to 
half the distance between escape wheel and pallet centers. 
Set off on each side of the center line one-half the number of 
teeth to be embraced by the pallets and from the points of 
the outside teeth draw lines tangent to the circle described 
from the pallet center. These lines would then form the 
faces of the pallets if they w^ere left flat." 

We wonder how much information this description and 
the drawing conveys to the average reader. How long 
should the pallets be? What is the drop? How much will 
the escape wheel recoil w^ith such a depthing? What arc 
will the pallets give the pendulum ? Why should the center 
distance always be the same (seven tenths of the diameter 
of the wheel) whether the escapement embraces eight, or ten, 
or six teeth ? As a matter of fact it should not be the same. 
We could ask a few more questions as to other details of 
this formula, but it will be seen that such a description is 



144 



THE MODERN CLOCK. 



practically useless to all but those who are already so skilled 
that they do not need it. 




Fig. 42. Recoil Escapement with Curved Lifting Planes. 



Let us analyze these drawings. A little study of Figs. 
41, 42 and 43 will show that there is really only one point of 
difference between them and Fig. 32, which shows the ele- 



THE MODERN CLOCK. 



H5 



ments of the Graham, or dead beat. The sole difference is 
in the fact that there are no separate locking planes in the 
recoil, the locking and run taking place on an extension of 
the lifting planes. Otherwise we have the same elements 
in our problem and it may therefore be laid out and handled 




V -L 



Fig. 43. Drawing the Lock Lift and Recoil of the Usual Form. 



in the same manner; indeed, if we were to set off on Fig. 
32, the amount of angular motion of the pallet fork which 
is taken up by the run of the escape wheel teeth on the 
locking planes, by drawing dotted lines above the tangents, 
T, we should then have measured all the angles necessary to 
intelligently set out the recoil escapement. We should have 
the lock at the tangent, T, the lift and the run (or recoil) 



146 



THE MODERN CLUCK. 



being defined by the lines on either side of it, and the length 
of our running and lifting planes would be found for the 
entering pallet by drawing a straight line between the points 
of the two acting teeth of the escape wheel and noting 
where this line cut the lines of recoil and lift. A similar 
line traced at right angles to this would in the same way 




Fig. 43. Show in 



lie Usual- Position in Cheap Clocks and the Verge 
Wire. 



define the limits of run and lift on the exit pallet. It will 
therefore be seen that our center distances for any desired 
angle of escapement may be found in the same way (Fig. 
28), for either escapement, and thus the method of making 
the pallets for the ordinary American clock, Fig. 43, be- 
comes readily intelligible. The sole object of curving the 
pallets, as explained previously, was to decrease the butting 
effect of the run on the points of the teeth. This is ac- 



THE MODERN CLOCK. 



147 



complished in Fig. 43 by straight planes on the pallets and 
straight sides to the teeth with 20° teeth on the escape 
wheel; merely inclining the plane of the entering pallet 
about six degrees toward the escape wheel center, thus serv- 




Fig. 44. Recoil with Curved Planes. 



ing all purposes, 'while the gain in the cost of manufacture 
by using straight instead of curved pallets and wheel teeth 
is very great. 

One factory in the United States is turning out 2,000,000 
annually of two movements, or about 1,000,000 of each 
movement; there are four other larger factories and several 



148 TJIE MODERN CLOCK. 

with a less product; so it will readily be seen that any de- 
crease in cost, however small it may be on a single move- 
ment, will run up enormously on a year's output. Suppose 
the factory mentioned were enabled to save only one-eighth 
r>f a cent on one of its million movements manufactured last 
year, this would amount to $1,250 per year, a little over 
$100 per month. Thus it will be seen that close figuring on 
costs of production is a necessity. 







Fig. 46. Drum Escapement. 

Fig. 44 shows the method of drawing the escapement 
according to the common sense deductions given above. As 
the methods of laying out the angle of escapement, lock, lift, 
and run, were given in detail in Figs. 28 to 32, they need not 
be repeated here. 

Fig. 46 shows the escapement frequently used in French 
"drum'' clocks and hence called the "Drum"' escapement. 
These are clocks fitted to go in any hole of the diameter of 
the dial and hence they have very short, light pendulums. 
An attempt is made to gain control over the pendulum by 



THE MODERN CLOCK. I49 

decreasing the arc of escapement to not more than two and 
sometimes to only one tooth. This gives an impulse to the 
pendulum only on one-half of the vibrations, the escape 
wheel teeth resting and running on the long circular locking 
pallet during alternate swings of the pendulum. The idea 
is that the friction of the long lock will tend to reduce the' 
effect of the extra force of the mainspring when the clock 
is freshly wound. Such clocks often stop when the clock 
is nearly run down, from deficiency of power, and stop 
when wound, because the friction of the escape wheel teeth 
on the locking plane is such as to destroy the momentum 
of the light pendulum. All that can be done in such cases 
is to alter the locking planes as shown by the dotted lines, 
so that the "drum" becomes virtually a recoil escapement 
of two teeth. ' 



CHAPTER XI. 

THE DENNISON OR GRAVITY ESCAPEMENT. 

The distinguishing feature of this escapement lies in the 
fact that it aims to drive the pendrlum by appl}dng to it a 
falling weight at each excursion on each side. As the weight 
is lifted by the train and applied to the pendulum on its re- 
turn stroke and there is no other connection, it follows that 
the pendulum is more highly detached than in any other 
form of pendulum escapement. This should make it a bet- 
ter time-keeper, as the application of the weight should give 
a constant impulse and hence errors and variations in the 
power which drives the train may be neglected. 

On tower clocks this is undoubtedly true, as these clocks 
are interfered with by every wind that blows against the 
hands, so that a detached pendulum enables a surplus of 
power to be applied to the train to meet all emergencies. 
With a watchmaker's regulator, however, the case is dif- 
ferent. Here every effort is made to favor the clock, vibra- 
tions, variations of temperature, variations of power, dirt, 
dust, wind pressure and irregularities of the mechanism are 
all carefully excluded and the consequence is that the spe- 
cial advantages of the gravity escapement are not apparent, 
for the reason that there are practically no variations for 
the escapement to take care of. Added to this we must con- 
sider that the double three-legged form, which is the usual 
one, is practically an escape wheel of but six teeth, so that 
another wfleel and pinion must be added to the train and this, 
with the added complications of the fan and the heavier driv- 
ing weight required, counterbalance its advantages and bring 
it back to an equality of performance with the simpler mech- 
anism of the well made and properly adjusted dead beat es- 

150 



THE MODERN CLOCK. I^I 

capement. Theoretically it should work far better than the 
dead beat, as it is more detached ; but theory is always modi- 
fied by working conditions and if the variations are lacking 
there is no special advantage in constructing a mechanism 
to take care of them. This is the reason why so many 
watchmakers have constructed for themselves a regulator 
with this escapement, used in the making all the care and 
skill of which they were capable and then been disappointed 
to find that it gave no better results with the same pendulum 
than the dead beat it was to replace. They had eliminated 
all the conditions under which the detached escapement 
would have shown superiority. 

Although the gravity escapement will not give a superior 
performance under the most favorable conditions for time- 
keeping, it is distinctly superior when these conditions are 
unfavorable and therefore fully merits its high place in the 
estimation of the horological fraternity. We have instanced 
its value in tower clock work; it has another advantage in 
running cheap and poorly made (home made) regulators 
with rough and poor trains ; therefore, it is a favorite escape- 
ment with watchmakers who build their ow^n regulators 
while they are still working at the bench, before entering 
into business for themselves. As the price. of a first-class 
clock for this purpose is about $300 and the cheapest that is 
at all reliable is about $75, it will be seen that the tempta- 
tion to build a clock is very strong and many of them are 
built annually. 

Regulators with the gravity escapement are built by the 
Seth Thomas Clock Co., the Howard, and one or two others 
in this country, but they are furnished simply to supply the 
demand and sales are never pushed for the reasons given 
previously. Clocks with this escapement are quite common 
in England and many of them have found their way to 
America. It is one of the anomalies of trade that our clock- 
makers are supplying Europe with cheap clocks, while we 
are importing practically all the high-priced clocks sold in 



153 



THE MODERN CLOCK. 




Fig. 47. 



THE MODERN CLOCK. I53 

the United States and among them are a few having the 
three-legged and four-legged gravity escapements, therefore 
the chances are that when a repairer finds such a clock it is 
likely to be either of English origin or homemade, unless it 
be a German regulator. 

Figs. 47 and 48 show plans and side views of the three- 
legged escapement. Fig. 48 also shows an enlarged view of 
the escape wheel, showing how the three-leaved pinion be- 
tween the tw^o escape wheels, is made where it is worked 
out of the solid. A, B and C and a, b and c show the escape 
wheel which is made up of two three-armed wheels, one on 
each side of a three-leaved pinion marked D^ and D^ in the 
enlarged view of Fig. 48. The pallets in this escapement 
consist of the two arms of metal suspended from points op- 
posite the point of bending of the pendulum spring and the 
lifting planes are found on the ends of the center arms in 
these pallets, which press against the three leaves of the 
pinion, while the impulse pins e^ and e-. Fig. 47 and 48 act 
directly upon the pendulum in place of the verge wire. The 
pallets act between the wheels in the same plane as each 
other. The lifting pins or pinion leaves act on the lifting 
planes after the line of centers when the long teeth or legs 
of the escape wheels have been released from the stops, F 
and G, Figs. 47 and 48, which are placed one on each side 
of the pallets and act alternately on the wheels. These pal- 
lets are pivoted one on each side of the bending point of the 
suspension spring. To lay out the escapement, draw a cir- 
cle representing the escape wheel diameter, then draw the 
line of centers and set off on the diameter of the escape 
wheel from each side of the line of centers 60° of its cir- 
cumference, thus marking the positions for the pallet stops 
120° apart. Draw radii from the center of the escape wheel 
to these positions and draw tangents from the ends of these 
radii toward the center line. The point where these meet 
will be the bending point of the pendulum spring. 



154 



THE MODERN CLOCK. 




Fig. 48. 



THE MODERN CLOCK. I55 

This is clearly shown at H, Fig. 47. The points of sus- 
pension for the pallets are planted on the line of these tan- 
gents and a little be!ow the point H, where the tangents meet 
on the line of centers. This is done to avoid the mechanical 
difficulty of having the studs for the two pallets occupy the 
same place at the same time. The arms of the pallets below 
the stops may be of any length, but they are generally con- 
structed of the same angle as the upper arms and will be 
all right if drawn parallel to these upper arms. They are in 
some instances continued further down, but this is largely 
a matter of taste and the lower portion of the escapement is 
generally drawn so as to be symmetrical. 

The impulse of the pendulum is given by having pins prO" 
jecting from the pallet arms and bearing upon the pendulum 
rod, which pins may be of brass, steel or ivory. In the 
heavier escapements they are made of ivory in order to avoid 
any chatter from contact with the pendulum rod of a heavy 
pendulum. These pallets should be as light as it is possible 
to make them without having them chatter under the im- 
pact of the escape wheel arms on the stops. They have only 
to counteract the force of the pendulum spring and the re- 
sistance of the air and for light pendulums this force is much 
less than is generally understood. Two ounces of impulse 
will maintain a 250-pound pendulum, but two pennyweights 
is more than sufficient for a fifty-pound pendulum. The 
reader can see that in the case of a pendulum weighing but 
eight to fourteen pounds, there w^ill be a still greater pro- 
portionate drop, as the spring itself is thinner, the rod is 
thinner, the pendulum ball oi¥ers little resistance to the air 
and the consequence is that it is difficult to get the pallet 
arms light enough for an ordinary clock. 

Watchmakers who make this escapement for themselves, 
to drive an eight to fourteen pound pendulum., generally 
make the escape wheel three inches diameter and make the 
escape wheel and pallet arms all from the steel obtained by 
buying an ordinary carpenter's saw. The lifting planes 



1^6 THE MODERN CLOCK. 

should not be more than one-eighth its diameter from the 
center of the escape wheel, as where this is the case the 
circular motion of the center pins will be so great that the 
pallet in action will be thrown out too rapidly and will chat- 
ter when striking the pendulum rod. On the other hand it 
should not be less than one-twelfth of the diameter of the 
escape wheel, or the pendulum will not be given sufficiently 
free swing and the motion will be so slow that while such a 
clock will work under favorable conditions, jarring, shak- 
ing in wind storms, etc., will have a tendency to make the 
pendulum wabble and stop the clock. From what has been 
said above, it will also be seen that the necessity for slow 
motion of the pallet arms unfits this escapement for use with 
short pendulums. 

The action of the escapement is as follows : The pendu- 
lum traveling to the right, when it has thrown the right 
pallet arm sufficiently far, will liberate the escape wheel 
tooth from the stop G and the pinion, acting on the lifting 
plane, will raise the pallet arm, allowing the pendulum to 
continue its course without doing any further work until 
it has reached nearly its extreme point of excursion, when 
the weight of the pallet will be dropped upon the pendulum 
rod and remain there, acting upon the pendulum until it has 
passed the center when the pallet arm will be stopped by the 
banking pin M^ ; exactly the same procedure takes place on 
the left side of the escapement during the swing of the pen- 
dulum to the left. The beat pins M and M^ should be set 
so that the impulse pins e^ and e^ will just touch the pen- 
dulum when the latter is hanging at rest and the escapement 
will then be in beat. The stops should be cut from sheet 
steel and the locking faces of the escape wheel arms, stops 
on the pallets, lifting planes of the pallets and the lifting pins 
should all be hardened. In some of the very fine escape- 
ments the faces of the blocks are jeweled. The arnis of the 
inner part of the escape wheel are usually set at equal an- 
gular distances between those of the outer, although this is 



THE MODERN CLOCK. 



157 



not absolutely necessary, and the lifting pins are set on radii 
to the acting faces of the arms of one of the wheels, so as to 
cross the line of centers at the distance from the center, not 
exceeding one-eighth of the radius of the wheel, for the 
reasons explained above. 




Fig. 49. 

From the comparatively great angle at which the arms are 
placed, the distance through which they have to be lifted to 
give sufficient impulse is less in this escapement than in one 
with a larger number of teeth acting in the same plane, as 
the pallets would then hang more nearly upright. This is a 
great advantage, as the contact is shorter. The unlocking is 
also easier for the same reason, and from the greater diame- 
ter of the wheel in proportion to other parts of the escape- 



138 THE MODERN CLOCK. 

ment, the pressure on the stops is considerably less. The two 
wheels must be squared on the arbor, so there will be no 
possibility of slipping. The lifting pins D are shouldered 
between them like a three-tooth lantern pinion. In small 
escapements the lifting pins are not worked out of the solid 
arbor, but are made as hardened screws to connect the two 
portions of the wheel. In tower clocks the pinion is gener- 
ally made solid on the shaft J, Fig. 48. The wheel, A, B, C, 
is made to pass over the pinion D and is fitted to a trian- 
gular seat, the size of the triangle of the leaves, D, against 
the collar on the shaft. The other wheel, a, b, c, is fitted 
to the inside triangle of the pinion, so that the leaves, D, 
form a shoulder against which it fits. The pallets, E and E^, 
also lie in one plane between the wheels, but one stop, F, 
points forward to receive the A, B, C, teeth and the other, 
G, points backward to receive the a, b, c teeth alternately. 
The distance of the pendulum top, H, or cheeks from the 
center of the escape wheel, J equals the diameter of the 
escape wheel. The lifting pins should be so placed that the 
one which is holding up a pallet and the one which is to lift 
next will be vertical over each other, on the line of centers, 
the third pin being on the level with the center, and to one 
side of it, see Fig. 48, enlarged view. 

The fly is a very essential part of this escapement, as the 
angular motion of the escape wheel is such that unless it 
were checked it would be apt to rebound and unlock; con- 
sequently, a large fly is always a feature of this escapement 
and is mounted upon the scape wheel arbor with spring fric- 
tion in such a way that the fly can continue motion after the 
scape wheel has been stopped. This is provided for by a 
spring pressure, either like the ordinary spring attachment 
of the fly of striking trains of small clocks, or as shown in 
Fig. 49 for tower clocks. This fly is effective in propor- 
tion to its length and hence a long narrow fly will be better 
than a shorter and wider one, as the resistance of the air 



THE MODERN CLOCK. 



159 




Fig, 50. 



l6o THE MODERN CLOCK. 

striking against the ends of the fly is much greater the fur- 
ther you get from the center. 

The pallet stud pins and the impulse pins should on no 
account be touched with oil or other grease of any kind, 
-but be left dry whatever they are made of, because the slight- 
est adhesion betw^een the impulse pins and the pendulum rod 
is fatal to the whole action of the escapement. Care must 
also be taken that one pallet begins to lift simultaneously 
with the resting of the other, neither before nor after. 

The gravity escapement requires a heavier weight or 
force to operate the train than a dead beat escapement, be- 
cause it must be strong enough to be sure of lifting the pal- 
lets quickly and firmly, and also because the escape wheel 
having but six teeth necessitates the use of another wheel 
and pinion between the escape and center and consequently 
the train is geared back more than it would be for a dead 
beat escapement, with the seconds hand mounted on the es- 
cape wheel arbor. But with this form of escapement the 
superfluous force does not work the pendulum and it does 
no harm if the train is good enough not to waste power in 
getting over rough places left in cutting the teeth of the 
wheels or any jamming from those which have unequal 
widths or spaces. For this reason a high numbered train is 
better than a low numbered one, as these defects are greater 
on the teeth of a low numbered train and any defect in such 
cases will show itself. 

In the gravity escapement the escape wheel must have a 
little run at the pallets before it begins to lift them and in 
order to do this the banking pins, M, M^, for the pallet arms 
to rest on, should hold them just clear of the lifting pins 
or leaves of the escape wheel. The escape wheel should be 
as light as possible, for every blow heard in the machine 
means a loss of power and wear of parts. Of course, in an 
escapement a sudden stop is expected, but the light wheel 
will reduce it to a minimum if the fan is large enough. Par- 
ticular attention should therefore be given to the length of 



THE MODERN CLOCK. 



i6i 




O 



Fig. 51. 



l62 THE MODERN CLOCK. 

this fan and if the stop of the escape wheel seems too ab- 
rupt, the fan should be lengthened. 

Figs. 50 and 51 show the same escapement with a four- 
legged wheel instead of the double three-legged. In this 
case, where there is but one wheel, the pallets must of ne- 
cessity work on opposite sides of the wheel and hence they 
are not planted in the same plane with each other, but are 
placed as close to each side of the wheel as is practicable. 

To lay out this escapement, draw the circle of the escape 
wheel as before, make your line of centers and mark off on 
the circle 6yy2° on each side of the line of centers and draw 
radii to these points, which will indicate the approximate 
position of the stops. Tangents to these radii, meeting above 
the wheel on the line of centers will give the theoretical 
point of the suspension. One set of the lifting pins is 
planted on radii to the acting faces of the teeth of the es- 
cape wheel. The opposite set, on the other side of the wheel, 
is placed midway between the first set. This secures the 
lifting at the line of centers. The wheel turns 45° at each 
beat and its arbor likewise carries a fly. 

In case the locking is not secure, the stops may be shifted 
a little up or down, care being taken to keep them 135° 
apart. In this way a draw may be given to the locking of 
the scape wheel arms similar to the draw of the pallets in 
a detached lever escapement and thus any desired resistance 
to unlocking may be secured. The stops in either escape- 
ment are generally made of steel and it is of the utmost, im- 
portance that. the arms of the escape wheel should leave them 
without imparting the least suspension of an impulse. 
Therefore, the stops and the ends of the arms should be cut 
aAvay (backed off) to rather a sharp angle to insure clear- 
ance when the arms are leaving the stops. It is also of 
equal importance that the legs of the wheels should fall on 
the stops dead true. The fit of each of the legs should be 
examined on both stops with a powerful eye glass, so that 
they should be correct and also see that when the unlock- 
ing takes pl?ce the wheel is absolutely free to turn. 



CHAPTER XII. 

THE CYLINDER ESCAPEMENT AS APPLIED TO CLOCKS. 

We remarked in a previous chapter that the Hfting planes 
were sometimes on the wheel and sometimes on the anchor. 
In another chapter we pointed out clearly that the run on the 
locking surface of the pallets had an important bearing on 
the freedom of the escapement and hence on the rate of the 
dead beat escapement. In considering the cylinder escape- 
ment, so common in carriage clocks, we shall find t'tiat the 
lift is almost entirely on the curved planes of the escape 
wheel, and that the locking planes are greatly extended, so 
that they form the outer and inner surfaces of the cylinder 
walls. Thus \ve have here a form of the dead beat escape- 
ment, which embraces but one tooth of the escape wheel 
and is adapted to operate a balance instead of a pendulum. 
Therefore the points for us to consider are as before, the 
amount of lift, lock, drop and run, and the shapes of our 
escape wheel teeth to secure the least friction, as our lock- 
ing surfaces (the run) being so greatly extended this mat- 
ter becomes important. 

Action of the Escapement. — Fig. 52 is a plan of the cyl- 
inder escapement, in which the point of a tooth of the escape 
wheel is pressing against the outside of the shell of the 
cylinder. As the cylinder, on which the balance is mounted, 
is moved around in the direction of the arrow, the wedge- 
shaped tooth of the escape wheel pushes into the cylinder, 
thereby giving it impulse. The tooth cannot escape at the 
other side of the cylinder, for the shell of the cylinder at 
this point is rather more than half a circle ; but its point 
locks against the inner side of the shell and runs there till 

163 



164 



THE MODERN CLOCK. 



the balance completes its vibration and returns, when the 
tooth which was inside the cylinder escapes, giving an im- 
pulse as it does so, and the point of the succeeding tooth 
is caught on the outside of the shell. The teeth rise on 
stalks from the body of the escape wheel, and the cylinder 
is cut away just below the acting part of the exit side, leav- 




Fig. 52. a, wheel; b, cylinder; f, stalk on which teeth are mounted. 

ing for support of the balance only one-fourth of a circle, 
in order to allow as much vibration as possible. This will 
be seen very plainly on examining Fig. 53, which is an ele- 
vation of the cylinder to an enlarged scale. 



Proportion of the Escapement.— The escape wheel has 
fifteen teeth, formed to give impulse to the cylinder during 
from 20° to 40° of its vibration each way. Lower angles 
are as a rule used with large than with small-sized escape- 



THE MODERN CLOCK. 



165 



rrtents, but to secure the best result either extreme must be 
avoided. In the escapement with very slight inclines to the 
wheel teeth, the first part of the tooth does no work, as the 
tooth drops on to the lip of the cylinder some distance up 
the plane. On the other hand, a very steep tooth is almost 
sure to set in action as the oil thickens. The diameter of 




Fig. 53. 



the cylinder, its thickness and the length of the wheel teeth 
are all co-related. The size of the cylinder with relation to 
the wheel also varies somewhat with the angle of impulse, 
a very high angle requiring a slightly larger cylinder than 
a low one. If a cylinder of average thickness is desired for 
an escapement with medium impulse, its external diameter 
may be made equal to the extreme diameter of the escape 
wheel multiplied by 0.T15 



66 



THE MODERN CLOCK. 



Then to set out the escapement, if a Hft of say 30° be 
decided on, a circle on which the points of the teeth will 
fall is drawn within one representing the extreme diameter 
of the escape wheel, at a distance from it equal to 30'' of 
the circumference of the cylinder. Midway between these 




\i^' \ \ < 



V30» -i 




Fig. 54, 



two circles the cylinder is planted (see Fig. 54). If the 
point of one tooth is shown resting on the cylinder, a space 
of half a degree should be allowed for freedom between 
the opposite side of the cylinder and the heel of the next 
tooth. From the heel of one tooth to the heel of the next 
equal 24° of the circumference of the wheel, 360-^15=24°, 
and from the point of one tooth to the point of the next 



THE MODERN CLOCK. 167 

also equals 24° so that the teeth may now be drawn. They 
are extended within the innermost dotted circle to give them 
a little more strength, and their tips are rounded a little, 
having the points of the impulse planes on the inner or 
basing circle. The backs of the teeth diverge from a rad- 
ial line from 12° to 30°, in order to give the cylinder clear- 
ance, a high angled tooth requiring to be cut back more 
than. a low one. A curve whose radius is about two-thirds 
that of the wheel is suitable for rounding the impulse planes 
of the teeth. The internal diameter of the cylinder should 
be such as to allow a little freedom for the tooth. The 
rule in fitting cylinders is to have equal clearance inside and 
outside, so as to equalize the drop. The acting part of the 
shell of the cylinder (where the lips are placed) should be 
a trifle less than seven-twelfths of a whole circle, with the 
entering and exit lips which are really the pallets, rounded 
as shown in the enlarged plan, Fig. 55, the entering lip or 
pallet rounded both ways and the exit pallet rounded from 
the inside only. This rounding of the lips of the cylinder 
adds a little to the impulse beyond what would be given 
by the angle on the wheel teeth alone. The diameter of 
the escape wheel is usually half that of the balance, rather 
under than over. 

Size of Cylinder Pivot. — To establish the size of the 
pivot with relation to its hole i^ apparently an easy thing to 
do correctly, but to an inexperienced workman it is not so. 
The side shake in cylinder pivot holes should be greater 
than that for ordinary train holes ; one-sixth is the amount 
prescribed by Saunier ; the size of the pivot relatively to the 
cylinder about one-eighth the diameter of the body of the 
cylinder. It is very necessary that this amount of side 
shake should be correctly recognized ; if less than the amount 
stated, the escapement, though performing well while the 
oil is fresh, fails to do so when it commences to thicken. 

When the balance spring is at rest, the balance should 



THE MODERN CLOCK. 



69 



have to be moved an equal amount each way before a tooth 
escapes. By gently pressing against the fourth wheel with 
a peg this may be tried. There is generally a dot on the 
balance and three dots on the plate to assist in estimating 
the amount of lift. When the balance spring is at rest, the 
dot on the balance should be opposite to the center dot on 
the plate. The escapement will then be in heat, that is, pro- 
vided the dots are properly placed, which should be tested. 
Turn the balance from its point of rest till a tooth just drops, 
and note the position of the dot on the balance with refer- 
ence to one of the outer dots on the plate. Turn the bal- 
ance in the opposite direction till a tooth drops again, and 
if the dot on the balance is then in the same position with 
reference to the other outer dot, the escapement will be in 
beat. The two outer dots should mark the extent of the 
lifting, and the dot on the balance would then be coincident 
with them as the teeth dropped when tried in this way ; but 
the dots may be a little too wide or too close, and it will 
therefore be sufficient if the dot on the balance bears the 
same relative position to them as just explained ; bnt if it 
is found that the lift is unequal from the point of rest, the 
balance spring collet must be shifted in the direction of the 
least lift till the lift is equal. A new mark should then be 
made on the balance opposite to the central dot on the 
plate. 

When the balance is at rest, the banking pin in the balance 
should be opposite to the banking stud in the cock, so as to 
give equal vibration on both sides. This is important for 
the following reason. The banking pin allows nearly a 
turn of vibration and the shell of the cylinder is but little 
over half a turn, so that as the outside of the shell gets round 
towards the center of the escape wheel, the point of a tooth 
may escape and jam the cylinder unless the vibration is 
pretty equally divided. When the banking is properly ad- 
justed, bring the balance round till the banking pin is 
against the stud; there should then be perceptible shakL' 



170 THE MODERN CLOCK. 

between the cylinder and the plane of the escape wheeL Try 
this with the banking- pin, first against one and then against 
the other side of the stud. If there is no shake, the wheel 
may be freed by taking a little off the edge of the passage 
of the cylinder where it fouls the wheel, by means of a sap- 
phire file, or a larger banking pin may be substituted at the 
judgment of the operator. See that the banking pin and 
stud are perfectly dry and clean before leaving them : a 
sticky banking often stops a clock when nearly run down. 
Cylinder timepieces, after going for a few months, some- 
times increase their vibration so much as to persistently 
bank. To meet this fault a weaker mainspring may be 
used, or a larger balance, or a wheel with a smaller angle 
of impulse. By far the quickest and best way is to very 
slightly lap the wheel by holding a piece of Arkansas stone 
against the teeth, afterwards polishing with boxwood and 
red stuff. So little taken off the wheel in this way as to be 
hardly perceptible will have great effect. 

Sometimes the escape wheel has too much end shake. We 
must notice in the first place how the teeth are acting in the 
cylinder slot. Suppose, when the escape wheel is resting 
upon its bottom shoulder, the cylinder will ride upon the 
plane of the wheel, which will cause it to kick or give the 
wheel a trembling motion, then we know that the cylinder 
is too low for the wheel ; therefore, we have not only to 
lower the escape top cock in order to correct the end shake, 
but we must also drive the bottom cylinder plug out a little 
in order to raise the cylinder sufficient to free it from the 
plane of the wheel. Now, if the end shake of the cylinder is 
correct previous to this, we shall now either have to raise 
the cock or drive the top plug in a little. But suppose the 
end shake of the escape pinion is excessive, and is, when the 
bottom shoulder is resting on the jewel, a little too low so 
that the bottom of the escape wheel runs foul of the cylinder 
shell ; in this case we simply drive out the steady pins from 
the bottom escape wheel cock and file a piece off the cock, 



TilE MODERN CLOCK. lyi 

leaving it perfectly flat when we have enough ofi. We then 
insert the steady pins again, screw it down, and if the end 
shake is right, the escapement is mostly free and right also. 

Now let us consider the frictions ; there is the resistance 
of the pivots, which depends on their radius, on the weight 
of the balance, the balance spring, the collet, and the weight 
of the cylinder; these are called locking frictions. Then 
there are those of the planes, of the teeth of the wheel, of the 
lips of the cylinder. It is on these that the change and de- 
struction of the cylinder are produced. To prevent this 
destruction, it is necessary to render the working parts 
of the cylinder very hard and well polished, as well as the 
teeth of the escape wheel. 

The oil introduced in the cylinder is also a cause as in the 
dead beat. It may thicken; the dust proceeding from the 
impact of the escapement forms with the oil an amalgam 
which wears the cylinder. The firmness and constancy of 
the cylinder depend on the preservation and fluidity of the 
oil. 

Then there are the accidental frictions ; the too close 
opening of the cylinder, the play of the balance and of the 
wheel, with the thickening of the oil, changes the arc of 
vibration a good deal; the teeth of the wheel may not be 
sufficiently hollowed, so that the cylinder can revolve in the 
remaining space, for the oil with the dust forms a thickness 
which also changes the vibration. The drop should not be 
too great, for it is increased by the thickening of the oil 
and impedes the vibration. 

Examination of Clocks. — In this particular escape- 
ment, when used for larger timepieces than watches, it is 
astonishing the variety of methods which are employed, yet 
the same results are expected. In examining such clocks 
we will first notice that the chariot, cock, etc., are so placed, 
many of them, that the last wheel in the train is a crown 
wheel, hence it is made to work at 90° with the escape wheel 



I'Ji THK MODEIIN CLOCK. 

pinion which is set at right angles with the crown wheel 
pinion, and, as a matter of course, the cylinder is also set 
the same way. Now, this arrangement needs especial care, 
for it is quite natural that when the entire friction of the 
cylinder is only on the bottom part of the bottom pivot, the 
clock is sure to go faster than when the whole length of 
both pivots are more in contact with their jewel holes, w^hich 
is always the case when the cylinder is parallel with all the 
pinions, instead of standing upon one pivot only. Now, al- 
though there must of necessity be a very great difference in 
timing the clock in the two different positions, yet we find 
no difference in the strength of mainspring or any part of 
the train, which is a mistake, for the result is simply this: 
the clock will gain time for the first few days after wind- 
ing, and will then gradually go slower and slower until the 
mainspring is entirely exhausted. It is not very difficult to 
ascertain why it goes so fast after winding, for then the 
whole tension of the spring is on, and as there is not suffi- 
cient friction on the point of one pivot to counteract this, 
the banking pin is almost sure to knock, and will continue to 
knock for the first few days until a part of the spring's 
pressure is exhausted. Now, in this case the knocking of 
the banking pin alone would cause the clock to gain time, 
even if the extra tension of the mainspring did not assist it 
to do so. Hence, on the whole, the result is anything but 
satisfactory, for such a clock can never be properly brought 
to time. 

Having said this much about the fault (which is entirely 
through the want of a little forethought with the manu- 
facturer), I will give as good a remedy as I can suggest 
to give the reader an idea of how these faults may be put to 
right, if he is willing to spend the time upon them. In the 
first place take out the cylinder and make the bottom pivot 
oerfectly flat instead of leaving it with a round end, as they 
are mostly left, which only allows just one part of the pivot 
to be in contact with the endstone. By leaving this pivot 



THE MODERN CLOCK. I73 

flat on the bottom, there is more surface in contact ; hence, 
in a sense, more friction. 

In some cases the whole pivot left flat would not be 
sufficient to retard the mainspring's force; then we must 
resort to other methods to effect a cure. 

Well, our next method in order to try and get the clock 
to be a uniform timekeeper, is to change the mainspring for 
one well finished and not quite so strong as the original 
one. Perhaps some will say "why not do this before we go 
to the trouble of flattening the bottom pivot?" Just this; 
when a pivot • is working only upon the bottom it is best 
to have a flat surface to work upon, as the balance is then 
oscillated with more uniformity, even when the mainspring 
is not exactly uniform in its pressure; therefore we do no 
harrur-but good^by making the bottom pivot flat, and this 
alone will sometimes be sufficient to cure the fault of the 
banking knocking if nothing else. 

To my mind, when such strong mainsprings are used as 
we generally see in this class of timepiece, neither of the 
jewel holes or pivots should be so small as they usually are. 
Fancy such small pivots as are mostly seen upon the escape 
wheel pinion being driven by such a strong mainspring. 
If we allow the clock to run down while the escape wheel 
is in place, we are very liable to find one or both pivots 
broken off before it gets run down. I think all such pivots 
ought to be sufficiently strong to stand the pressure of the 
mainspring through the train of wheels without coming to 
grief. But there is another reason why these pivots are 
liable to get broken off while letting the train run down ; that 
is, the badly pitched depth we often find in the crown wheel 
and escape wheel pinion. We frequently find too much 
end shake to the' crown wheel which, while resting one 
shoulder of the arbor against the plate puts the depth too 
deep, and on the other shoulder the depth is too shallow. 
l^QW, when the train is running rapidly this crown wheel is 
jumping about in the escape wheel pinion, so that the rough- 



174 THE MODERN CLOCK. 

ness of the running all helps to break off the escape wheel 
pivots. The best way to correct this depth is to notice how 
the screws fit in the cylinder plate — for these screws have 
to act as steady pins as well. If the holes where the screws 
go through are at all large, we then notice which would be 
the most convenient side to screw it securely in order to put 
a collet upon the shoulder of the crown wheel so that the 
depth will be right by making the end shake right with only 
fixing a collet to one shoulder. This depth, when correct, 
will also cause a more uniform pressure upon the escape- 
ment, and help to make the clock keep better time. We are 
supposing that this crown wheel is perfectly true, or it is not 
much use trying to correct the depth as mentioned above, 
for even if the end shake be ever so exact and the wheel 
teeth are out of true, we shall never get the depth to act as 
it ought, neither can the clock be depended upon for keep- 
ing going, regardless of keeping time. When this crown 
wheel is out of true it is best to rivet it true, not do as I 
h;ive seen it done, placed in the lathe and topped true, and 
then the teeth rounded up by hand. This n]ethod simply 
means a faulty depth after all, for in topping the teeth, those 
teeth which require the most topping will, when they are 
finished, be shorter from the top to the base than those 
v;hich do not get topped so much; therefore, some of the 
teeth are longer than the others, while the shorter ones are 
thicker ; for when the wheel was originally cut the teeth were 
all cut alike. These remarks will apply to several kinds of 
wheels; for whenever a wheel is topped to put it true, we 
may depend w^e are making a very faulty wheel of it unless 
we have a proper wheel cutting machine. 

The crown wheel must not be too thick because we will 
find the tooth to act with the inner edge, and what is left 
outside only endangers touching the pinion leaf which is 
next to come into action. Make sure the escape pinion is 
not too large, whicji sometimes happens. If it is, it must 
be reduced in size, or better, put in a new one. The crown 



THE MODERN CLOCK. 



175 



wheel holes must fit nicely and the end shake be well ad- 
justed. Do not spare any trouble in making this depth as 
perfect as you are able, as most stoppages happen through 
the faults in this place. It would be advisable, when sure 
the depth is correct, to drill two steady pin holes through 
the escapement plateau into the edge of the plates. When 
steady pins are inserted this will always ensure the depth 
being right when put together. 

In some of these clocks it is not only the crown wheel, 
but frequently the escape wheel has too much end shake. 
The former, as I have said, can be corrected by making a 
small collet that will just fit over pivot, fasten it on 
friction tight, place the wheel in the lathe and turn 
the collet down until it is the same size as the other part of 
the arbor, then run off the end to the exact place for the end 
shake to be right. If it is properly done and a steel collet is 
used, it will not be detected that a collet has been put on. 
Now, when the escape wheel end shake is wrong we have to 
proceed differently under different circumstances for we 
must notice in the first place how the teeth are acting in 
the cylinder slot. 

See that the cylinder and wheel are perfectly upright. 
Suppose, when the escape wheel is resting upon its bottom 
shoulder, the cylinder will ride upon the plane of the wheel, 
which will cause it to kick or give the wheel a. trembling 
motion, then we know that the cylinder is too low for the 
wheel ; therefore, we have not only to lower the escape top 
cock in order to correct the end shake, but we must also 
drive the bottom cylinder plug out a little in order to raise 
the cylinder sufficient to free it from the plane of the wheel. 
Now, if the end shake of the cylinder is correct previous to 
this, we shall either have to raise the cock or drive the top 
plug in a little. But suppose the end shake of the escape 
pinion is excessive, and is, when the bottom shoulder is 
resting on the jewel, a little too low so that the bottom of 
the escape wheel runs foul of the cylinder shell ; in this case 



176 THE MODERN CLOCK. 

we simply drive out the steady pins from bottom escape 
wheel cock and file a piece off the cock, leaving it perfectly 
flat when we have got enough off. We then insert the 
steady pins again, screw it. down, and, if the end shake is 
right, the escapement is mostly free and right also. It some- 
times happens that the wheel is free of neither the top nor 
bottom plug, but should this be the case, suflicient clearance 
may be obtained by deepening the opening with a steel pol- 
isher and oilstone dust or with a sapphire file. A cylinder 
with too high an opening is bad, for the oil is drawn away 
from the teeth by the escape wheel. 

If a cylinder pivot is bent, it may very readily be straight- 
ened by placing a bushing of a proper size over it. 

These clocks are very good for the novice to exercise his 
skill in order to thoroughly understand the workings of the 
horizontal escapement. He is better able to see how the 
different parts act with each other than he is in the small 
watch. When the escape is correct he will find that the 
plane of the escape wheel will work just in the center of 
the small slot in the cylinder. 

If he will notice how the teeth stand in the cylinder when 
the banking pin is held firmly upon the fixed banking pin, 
it will give him an idea of how this should be. At one side 
the lip of the cylinder is just about to touch the inside of the 
escape tooth, but the banking pin just prevents it from doing 
so, while on the other side the cylinder goes round just 
far enough to let the point of the next tooth just get on the 
edge of the slot, but it cannot get in owing to the interven- 
tion of the banking pin. If this is allowed to get in the slot 
just here, we then have what is called "a locking," which 
is, in reality, an overturned banking. If the other side is so 
that the banking pin does not stop it soon enough, the edge 
of the slot knocks upon the inside of the teeth and causes a 
trembling of the escape wheel, and the clock left in this 
form will never keep very good time. We may easily 
remedy this by taking off the hair spring collet; holding the 



THE MODERN CEOCK. 



77 



cylinder firmly in the plyers, and with the left hand turn 
the balance a little outwards; this will bring the banking 
pins in contact before the cylinder touches the inside of the 
wheel teeth, and all is right, providing we are careful in 
not doing it too much ; if so, we shall find the banking 
knock — a fault which is quite as bad, if not worse, than the 
one we are trying to remedy. Those particulars are the 
most important of anything in connection with the cylinder 
escapement. Yet, as this kind of clock is now being made 
up at such a low price, these seem^ing little items aie fre- 
quently overlooked ; hence, when they get into the hands 
of the inexperienced, there is often more trouble with them 




Fig. 56. 

than there need be if they knew where to look for some of 
the faults which I have been endeavoring to bring to light, 
There are several other things in connection with this par- 
ticular clock, but we will not comment further just now, 
but take them up when we are considering the trains, etc. 

In the meantime we will resume our study of the cylinder 
escapement with particular reference to badly worn or other- 
wise ill fitting escape wheels, as m.any times, the other points 
being right, the wheel and cylinder may be such as to give 
either too great or too small a balance vibration. 

A poor motion can also be due to a rough or a badly pol- 
ished cylinder, but such a cylinder wc rarely find. That 
with a wrong shape of the C3dinder lips the motion is not 
much lessened can be seen in quite ordinary movements 
where the quality is certainly not of the best neither are 
the lips correctly formed, nevertheless they have rather an 



178 THE MODERN CLOCK. 

excessive motion. To cover up these defects in such move- 
ments the cylinder wheel teeth are purposely given the shape 
as shown at B in Fig. 56, and to give sufficient power a 
strong mainspring is inserted. 
' With an excessive balance vibration we can usually con- 
clude that it is an intentional deception on the part of the 
manufacturer, while a poor motion can generally be ascribed 
to careless methods in making. The continued efforts in 
making improvements to quicken and cheapen manufactur- 
ing processes very frequently result in the introduction of 
defects which are only found by the experienced and practi- 
cal watchmaker 

As to the causes which induce excessive balance vibra- 
tions? As this defect is generally found in the cheaper 
grades of cylinder escapements, having usually rather small, 
heavy, and often clumsy balances, those which have balances 
whose weight is probably less than they ought to be, need 
not here be further considered, and it only remains for us 
to look to the cylinder or the escape wheel for the causes 
which produce these excessive vibrations. It will be found 
that the cylinder is smaller in diameter than usually em- 
ployed in such a size of clock ; the escape wheel is naturally 
also smaller, and its teeth generally resemble B, Fig. 56, 
while A shows the correct shape of a tooth for a wheel of 
that diameter. 

In using small cylinders we can give the escape wheel 
teeth a somewhcit greater angle of inclination than gener- 
ally used, but thnt tlic proper amount of incline is exceeded 
is proved by the fact that the balance vibrates more than 
two-thirds of a turn, it can also be readily seen that with a 
tooth like B a greater impulse must be imparted than one 
with an easy curve like A, and the impulse is still further 
increased as the working width of the tooth B (the lift) is 
greater, indicated by line h, w^iile the same line in a correct 
width of tooth, as shown at a, is considerably shorter. 



THE MODERN CLOCK. 



179 



In addition to what has been said of these escapements, w^ 
also find them provided with very strong mainsprings to 
give the necessary power to a tooth hke B with its steeply 
inclined lifting face or impulse angle. 

To decrease the great amplitude of ^he balance vibrations 
many watchmakers simply replace the strong mainspring 
with a weaker one. But this proceedure is not advantageous 
as the power of the escape wheel tooth is insufficient to 
start the balance going and this is due to two causes. First, 
the great angle of the escape wheel tooth, and secondly, the 
inertia of the balance. It is only by violently shaking such 
a clock that, we are enabled to start it going. And the 




Fig. 57. 



Fig. 58. 



owner soon becomes dissatisfied from its frequent stoppage 
due to setting of the hands and other causes so that he will 
be often obliged to shake it until it starts going once more. 
For properly correcting these defects the best method to 
pursue is to replace the cylinder wheel with another one, 
whose teeth are of the shape as shown at Fig. 55 and with- 
out question a good workman will always replace the 
escape wheel if the clock is of fair quality. But if a low 
grade one, we would hardly be justified in going to the ex- 
pense of putting in new wheels, as the low prices for which 
these clocks are sold preclude such an alteration. As we 
must improve the wheel some way to get a fair escapement 
action we can place it in a lathe and while turning, hold 



l8o THE MODERN CLOCK. 

an oil stone slip against it, we can remove the point S, Fig. 
56. After removing- the point the tooth will now have the 
form as shown at tooth C, Fig. 57. We now take a thin 
and rather broad watch mainspring, bending a part straight 
and holding it in the line / /, and revolving the wheel in the 
direction as shown b}^ the arrow, its action being indicated 
by figures i to 8; beginning at the point of the tooth at i, 
at 2 it comes in contact with the whole of the lifting face, 
and from 3 to 8 only on the projecting corner which was left 
by the oil stone slip in removing the heel of the tooth. In 
this way all the teeth are acted upon until the corner is en- 
tirely removed. Of course oil stone dust and oil is first 
used upon the spring for grinding, after which the teeth are 
polished with diamantine. Care must be observed in using 
the spring so as not to get the end / too far into the tooth 
circle, as it would catch on the heel of the preceding tooth. 

After the foregoing operation has been completed any 
feather edge remaining on the points of the teeth must be 
removed with a sapphire file and polished ; we will now have 
a tooth as indicated by D, Fig. 57. This shape of tooth can 
hardly be said to be theoretically correct, nevertheless it 
is a close approximation of the proper form of tooth, which 
is shown by the dotted lines, and will then perform its func- 
tions much better than in its original condition.. 

Fig. 58 also shows how the spring must be moved from 
side to side — indicated by dotted lines — so that the lifting 
face will have a gentle curve instead of being flat ; R repre- 
sents the tooth. 

After the wheel has been finished, as described, and again 
placed in the clock, it will be found that the balance makes 
only two-thirds of a turn, and as a result the movement can 
be easier brought to time and closely regulated. 

In the above I have described the cause of excessive bal- 
ance vibration, the method by which it can be corrected, and 
in what follows I shall endeavor to make clear the reasons 
for a diminished balance vibration or poor motion. It has 



THE MODERN CLOCK. l8l 

been probably the experience of most watchmakers to 
repair small cylinders of a low grade, having a poor motion 
or no motion at all, and it would hardly be profitable to 
expend much time in repairing them. But considerable 
time is often wasted in improving the motion by polishing 
pivots and escape wheel teeth, possibly replacing the cap 
jewels, or even the hole jewels, increasing the escapement 
depth or making it shallower, examining the cylinder and 
finding nothing defective, and as a last effort putting in a 
stronger mainspring. But all in vain, the balance seems 
tired and with a slight pressure upon an arm of the center 
wheel it stops entirely. 




Fig. 59. 

In this case, as in a former one, in fact, it is necessary 
at all times to carefully examine the cylinder wheel. j\Iy 
reason for not considering the cylinder itself so much as the 
wheel is that the makers of them have made a considerable 
advance in their methods of manufacture, so we find the 
cylinders fairly well made and generally of the correct size. 
Even if the cylinder is incorrectly sized, either too large oi 
small, it does not necessarilv follow that the watch would 
have a bad motion, as I have frequently had old movements 
where the cylinder was incorrectly proportioned and yet the 
motion was often a good, satisfactory one. Generally 
speaking, the cylinder escapement is one which admits of the 
worst possible constructive proportions and treatment, as 
we have often examined such clocks when left for repairs, 



l82 THE MODERN CLOCK. 

that, notwithstanding their being full of dirt, worn cylinder, 
broken jewel holes, etc., they have been running until one 
of the cylinder pivots has been completely worn away. 

It only remains to look for the source of the trouble in the 
escape wheel. If we examine the wheel teeth carefully, we 
shall find them resembling those in Fig. 59, the dotted lines 
representing the correct shape of the teeth for a wheel of 
that diameter. 

Why do we find wheels having such defective teeth ? This 
is probably due to their rapid manufacture, as they very 
likely had the correct shape when first cut, but by careless 
grinding and polishing they were gfiven improper forms, 
careless treatment being very evident at tooth F, which we 
find on examination has a feather edge at the point as well 
as at the heel of the tooth. If we grind these edges of the 
tooth with a ruby file, by placing it in the position as indi- 
cated by dotted lines h and /i^, and afterwards polishing the 
tooth point, we will find that the balance makes a better 
vibration. A wheel, having teeth like E, can still be used, 
but the balance will have a very poor motion, due to the fact 
that the impulse angle of the wheel tooth is too small ; the 
impulse faces of the teeth having so small an angle, are near- 
ly incapable of any action. With a tooth like G, if we 
should remove its bent point at the dotted line d, then th^ 
tooth would be too short, and as the inclination of the im- 
pulse face is incapable to produce a proper action, a new 
wheel must be used, having teeth as shown at Fig. 55. 

The reasons why a tooth, having the shape as shown at 
F and G (Fig. 59), will cause a bad action of the escapement 
and also why in such cases with a greater force acting on 
the wheel, causes a stopping of the clock, I will endeavor 
to explain with the aid of the illustration Fig. 60. Here we 
clearly see the curved points of the- teeth resting against the 
outer and inner walls of the cylinder while the escapement is 
in action. 



THE MODERN CLOCK. 



183 



Teeth H and H^ represent the defective tooth, while K 
and K^ shows a correctly formed tooth for a wheel of the 
same size, the correct depth and positions where the tooth 
strikes the inner and outer walls of the cylinder. It will be 
readily seen that the position of the tooth point upon the 
cylinder (at c) is most favorable in reducing the resistance 
to the least possible amount. But in the case of the teeth H 
and H^ the condition is entirely different. We find that it 
v/as necessary to set the escapement very deeply in order 
that it could perform its functions at all, and, as a conse- 




Fig 



quence, we have a false proportion ; the effects being con- 
siderably increased by the worst possible position of the 
teeth H and H^, where they touch the cylinder. While the 
cylinder c is turning in the direction shown by the arrows 
i i^j the tooth does not affect the cylinder to any extent ; but 
during the reverse movement of the cylinder, in the direction 
of 0^, an excessive amount of engaging friction must take 
place. A close inspection of the drawing will enable us to 
see that there is a great tendency of the cylinder to drag 
the tooth along with it during each of these motions. It is 
evident that in such a case the friction will eventually be- 
come so great as to lock the escapement, and if greater 
pressure is applied by any means to teeth H and H^, it is 
easily seen that this eifect will take place much. more rapidly. 
Replacing the escape wheel with one of correctly formed 
teeth and size is the best means at our disposal. 



CHAPTER XIII. 

THE DETACHED LEVER ESCAPEMENT AS APPLIED TO CLOCKS. 

As the clcck repairer is almost of necessity a watch- 
maker, or hopes to become one, and as he must enter deeply 
into the study of all questions pertaining to the detached 
lever in its various forms before he can make any progress 
at all in watchmaking, it w^ould seem unnecessary to repeat 
in these pages that which has already been so well said and 
so perfectly drr.\vn, described and illustrated by such author- 
ities as Moritz Grossman, Britten, Playtner and the various 
teachers in the horological schools, to say nothing of an 
equally brilliant and more numerous coterie of writers 
among the French, Germans and Swiss, so that the reader 
is referred to these writers for the mathematics and draw- 
ings which already so fully cover the technical and theo- 
retical properties of the detached lever escapement. A few 
words as to its adaptation to clocks may, however, not be 
out of place. 

Anyone who sees the clocks of to-day would be inclined 
to suppose that the first clocks wxre constructed with pendu- 
lums, because this is evidently the most simple and reliable 
system for clocks, and that the employment of the balance 
has been suggested by the necessity for portable time pieces. 
This is, however, not the case, for the first clocks had a 
verge escapement with a crude balance consisting of tw^o 
arms, carrying shifting weights for regulation. The pendu- 
lum Avas not used until about three hundred years after the 
invention of the first clock. 

After the invention of the dead beat escapement, with its 
great gain in accuracv by the reduction of the arc of pendu- 
lum oscillation, attempts were made to combine its many 
virtues with the necessarily large vibrations of a balance and 

184 



THE MODERN CLOCK. 



'85 



thus get all the advantages of both systems. By placing the 
lever on the arbor of the anchor, it was possible to multiply 
the small angle of impulse on the pallets very considerably 
at the balance, and to make all connection between them 
cease immediately after the impulse had been given. The 
dead beat escapement was thus converted into the detached 
lever escapement and the latter made available for both 
watches and clocks. Another important feature of this 



OE 



n 



u 



no: 



3E 



fl 



U 




Fig. 61. Pin Escapement for Clocks. 



escapement is that when properly proportioned it will not set 
on the locking or lifting, but will start to go as soon as 
power is applied to the escape wheel through the train. This 
cannot be said of the cylinder, duplex, or detent escape- 
ments, and it will be seen at once that this has an important 
influence upon the cost of construction, which must always 
be considered in the manufacture of cheap clocks in enor- 
mous quantities. 



l86 THE MODERN CLOCK. 

The lever escapement with pins for pallets and the lifting 
planes on the teeth of the escape wheel, which is the one 
usually put into cheap clocks, is from the theoretical point 
of view a very perfect form, because its lifting and locking 
lake place at exactly the same center distance and at the 
same angles, which again allows for greater latitude in 
cheap construction, while still maintaining a reasonably 
accurate rate of performance. These are the main reasons 
why the pin anchor has such universal use in cheap clocks. 

As this escapement is generally centered between the 
plates, banking pins are dispensed with by extending the 
counterpoise end of the lever far enough so that its crescent 
shaped sides will perform that office by banking against the 
scape wheel arbor; see Fig. 6i. The fork end of the lever 
engages with an impulse pin carried in the balance and the 
balance arbor is cut away to pass .the guard point or dart, 
thus doing away with the roller table. In other constructions 
the roller table is supplied in the shape. of a small brass collet 
which carries the pin and has a notch for the guard point, 
thus making a single roller escapement. 

The diameter of the lifting pins is generally made equal to 
2^ degrees of the scape wheel, which gives a lift of 2 de- 
grees on the pallet arms, and the remainder of the lift, 63^ 
degrees, must be performed by the lifting planes 
of the wheel teeth. The front sides of the wheel 
teeth are generally made with 15 degrees of draw and the 
lever should bank when the center of the pin is just a little 
past the locking corner of the tooth. Other details of the 
pin anchor escapement coincide with the ordinary pallet 
form, as used in watches, and the reader is referred for them 
to the works of the various authors mentioned previously. 

The trouble with the majority of these clocks is in the 
escapement and balance pivots, and to these parts are we 
going to direct particular attention, for often, be it ever so 
clean, the balance gets up a sort of ''caterpillar motion" that 
is truly distressing, and if no more is done we may expect 



THE MODERN CLOCK. 187 

a ''come back" job in a very short time. In taking down 
the movement the face wheels are left in place, but some- 
times it may be necessary to remove the "set wheel" of the 
alarm in order to proceed as we do. Remove the screws or 
pins that hold the plates together in the vicinity of the 
escapement, leaving the others, though if screws they may 
be loosened slightly; pry up the corner of the plate over 
the lever to loosen one pivot of same and let it drop away 
from the scape wheel sufficiently to let the wheel revolve 
until it is locked by a wire or pegwood previously inserted 
in the train, after which the plates can be pried apart more 
conveniently to permit the lever being removed entirely, also 
the scape wheel and the one next following. As nickel 
clocks differ in make-up, the operator must, of course, exer- 
cise judgment as to the work in hand to accomplish this. 

Have ready a straight-sided tin pail, with cover, that will 
hold at least one-half gallon of gasoline and of diameter 
large enough to receive the largest brass clock; remove 
the wire or pegwood and immerse the clock into the fluid 
and allow it to run down; this will loosen all the dirt and 
gummy oil and clean the clock very effectually. Let it re- 
main long enough for all the dirt to settle to the bottom of 
the pail ; then remove and wipe as dry as possible with a 
soft rag ; by having no binder on the spring it is permitted 
to uncoil to its full, and thereby remove all gummy oil be- 
tween its coils. Now peg out the holes of the wheels re- 
moved and of the lever and 'that portion of our work is 
complete. 

Polish or burnish the pivots of wheels either in a split 
chuck in the lathe, or by holding in a pin vise, resting the 
pivot on a filing block (an ivory one is best), and revolving 
between the fingers, using a smooth back file for burnishing, 
after the manner of pointing up a pin tongue, only let the 
file be held flat, so as to maintain a cylindrical pivot as nearly 
as possible. The scape wheel is now polished, i. e., the teeth, 
with a revolving bristle wheel on a polishing lathe, charged 



l88 THE MODERN CLOCK. 

with kerosene oil and tripoli. This will smooth up the teeth 
in fine form, especially those wheels that work into a lever 
with pin pallets. Clean the scape wheel by dipping into 
gasoline to remove all the oil and tripoli. The other wheel 
may simply be brushed in the gasoline or dipped and then 
brushed dry. 

We now turn our attention to the lever and closely ex- 
amine the pallets with a glass; if there are the least signs 
of wear upon them they must be removed. If the lever with 
pin pallets it is better to remove the steel pins and insert new 
ones. See if the holes in the anchor where they are inserted 
will admit a punch to drive them out from the back ; if not, 
open these holes with a drill until the ends of the pins are 
reached. Put a hollow stump with a sufficiently large hole 
in the staking tool, and by placing the pins in the stump 
they can be driven out successively, being sure that the 
driving punch is no larger than the pins ; drive or insert into 
their places a couple of needles of the proper size, and then 
break off at correct lengths; this completes the job in this 
particular style of lever. 

With the other style the job is not quite so easy ; with a 
pair of small round-nose pliers grasp the brass fork close up 
to the staff and bend it back from the pallets till it lays 
parallel with the staff; treat the counter poise of the fork 
in like manner ; place a thin zinc lap into the lathe, charged 
with flour of emery, and with the fingers holding the pallets 
grind off all wheel teeth marks on both the impulse and lock- 
ing faces of the pallets. Then polish with a boxwood lap 
charged with diamantine. It is surprising how speedily this 
can be done if laps are at hand. The only care necessary 
is not to round off the corners of the pallets, and as they are 
so large they can be easily held flat against the laps with 
the thumb and finger as before stated. Bend back the fork 
and counterpoise to their original position. The fork must 
now be attended to; see that no notches are worn in the 
horns of the fork by the steel impulse pin in the balance ; if 



THE MODERN CLOCK. 189 

the}^ appear they must be dressed out and polished, also ex- 
amine and smooth if necessary the ends of the horns that 
bank against the balance staff. These may seem small mat- 
ters, but they are often what cause all the trouble. 

We now come to the balance staff and the hardened 
screws in which the staff vibrates ; their irregularities are 
often the source of much vexation, and there is only one 
way to go at it and that is with a will and determination to 
make it right. Examine the points of the staff and see if 
they are in their normial shapes and are sharp and bright ; if 
so they will probably do their work. But we will suppose 
we have a bad case in hand and will therefore treat it thor- 
oughly according to our method. We find the staff is large 
in diameter and the ends are very blunt; the notch in the 
center has a burr on each side as hard as glass, making an 
admirable cause for catching the horns of the fork in some 
of the vibrations or in a certain position ; also the round part 
of the staff back of the notch is rough and looks as if it never 
had been finished, and, in fact, it has not, for it truly appears 
as if half, if not all, the nickel clocks are made to be finished 
by the watchmaker. - Remove the hairspring and place the 
staff between the jaws of your bench vise, with the jaws 
close up to the staff, but not gripping it, the balance ''hub" 
resting on the jaws with the impulse pin also down between 
the jaws. Have a block of brass about one-fourth inch 
square ; rest it on top of the staff, or on its pivot end, if it 
may so be called, holding it with the thumb and finger of 
the left hand. Strike this block with a hammer and drive 
out the staff ; a hollow punch is apt to be split in doing this, 
and as the pivot is to be re-pointed no harm will be done to 
ihc pivot or to the end of the staff. Draw the temper so it 
will work easily, insert into a split chuck and turn up new 
points ; have them long and tapering, that is, turn the points 
to a long slant from the end of the staff to the body of same, 
or at least twice as much taper as they generally have; 
polish off the back of the notch or round part of the staff 



190 



THE MODERN CLOCK. 



with an oil stone slip. Remove from the chuck, smear all 
over with powdered boracic acid by first wetting the staff in 
water, and then heat to a bright red and plunge straight into 
water; it will now be white and hard; draw the temper 
from the staff in the vicinity of the notch, leaving the pivot 
points hard as before; re-insert into the chuck and with 
diamantine polish the points and also around the staff in the 
vicinity of the notch. The drawing of the temper from the 
center of the staff to a spring temper is to make it less 
liable to breakage while driving on the balance. Fasten 
the staff tight in the vise and with a rather stout brass tube, 
large enough to step over the largest staff, drive on the 
balance to its former position. 

If the workman has a pivot polisher with a large lap, the 
job may be done, without softening the staff or removing 
the balance, by grinding the pivots. In turning the staff we 
often find it almost impossible to hold true. We straighten 
the best we can and then turn up our pivots, and as long as 
the untruth of the staff will not cause the balance to wabble 
to such an extent as to give us a headache or cause us to 
look cross-eyed it will do. W« do not -wish to be misunder- 
stood or to give the impression that we go on the principle 
of "good enough" ; but as gold dollars cannot be bought for 
seventy-five cents, neither can a workman devote the time to 
have everything perfect for fifty cents ; and for this very 
reason do they come in such an unfinished state from the 
mianufacturers. 

Next see if the two screws in which the balance vibrates 
have properly cut countersinks ; if rough or irregular, better 
at once draw the temper, re-drill with a sharp-angled drill 
and again harden. 

Occasionally a bunch of these clocks will come in with 
both pivots and cones badly rusted. This has generally been 
caused by acid pickling, or some sort of chemical harden- 
ing at the factory ; the acid or alkali gets into the pores of 
the steel and comes out after the clock has been shipped. 



THE MODERN CLOCK. 



191 



They are generally made in such quantities that fifty or a 
hundred thousand of them have been distributed before 
finding out that they were not right and then it is a matter 
of two or three years before the factory hears the last of it. 
The trouble is attributed to bad oil, or to anything else but 
the hardening, which is the real cause, and the expense of 
taking back and refitting the balance arbors and cones, 
paying freight both ways . and standing the abuse of dis- 
gruntled jewelers, goes on until life becomes anything but 
a -bed of roses. Every jeweler should warn the factory im- 
mediately on finding rust in the cones of a shipment of new 
clocks and not attempt to fix them himself, as such a fault 
cannot be discovered at the factory and every day it con- 
tinues means more thousands of clocks distributed that will 
give trouble. 

Our clock is now ready to be put together. Wind up the 
spring and slip on the binder; then put in the wheels and 
lever ; then adjust the balance and hairspring to their proper 
places, slightly wind the mainspring and then see (by bring- 
ing either horn against the staff) whether it sticks and holds 
the balance ; if so, shorten the fork slightly by bending ; try 
this until the balance and fork act perfectly free and safe. 
Slightly oil the balance pivots; an excess will only gather 
dust and prove detrimental, as the countersinks form an ad- 
mirable place for holding the dust. Now oil the remaining 
parts and we are sadly mistaken if our clock does not make 
a motion that will be gratifying. 

The foregoing process may seem tedious and uncalled for 
and too close m.ention made of the lesser portions of the 
work, but we must not ''despise the day of small things," 
and as we are watchmakers, we are expected to do this 
work, even though troublesome and the pay small ; we 
should also bear in mind that if we only make a nickel 
clock run and keep fair time, it will be a large advertise- 
ment, and possibly repay tenfold. It takes only an hour to 



192 THE MODERN CLOCK. 

do this job complete, while in many cases only the balance 
staff needs attention. 

Sometimes such a clock will be apparently all right me- 
chanically but will continue to lose time ; then it is probable 
'that the balance does not make the proper number of vibra- 
tions, which causes the clock to lose time. There is one way 
to tell this, which will soon locate the trouble: count 
the train to ascertain the number of vibrations the balance 
should make in one minute. You do this by counting the 
number of teeth in the center wheel, which we will say is 48; 
third wheel 48; fourth wheel, 45; escape, 15. Multiply all 
teeth together, which give us 48x48x45x15 = 1,555,200. 
Now count the leaves in the third wheel pinion, which is 
6 ; fourth, 6 ; escape, 6. Multiply these together, 6x6x6 = 
216; now divide the leaves into the teeth, 1,555,200^-216 
= 7,200, w^hich is the number of whole vibrations some An- 
sonia alarm clocks make in one hour. Dividing 7,200 by 60 
gives us 120, the number of vibrations per minute. Now the 
balance must make 120 vibrations in one minute, counting 
the balance going one way. If the balance only vibrates 
118, the clock will lose time and the hairspring must be 
taken up or made shorter, until it makes the required num- 
ber of vibrations. If it should vibrate 122 the clock would 
gain ^nd the hairspring should be let out. 

Find out the number of vibrations your balance should 
make and work accordingly; and if you find that the bal- 
ance makes the proper number of vibrations in one minute, 
then the trouble must lie in the center post, which has not 
enough friction to carry the hands and dial wheels, or the 
wheel that gears into the hour wheel and regulates the 
alarm hand is too tight and holds back the hands. You 
should find some trouble about these wheels or center post, 
for where a balance makes the proper number of vibrations 
in one minute, the minute hand cannot help going around 
if everything else is correct. 



THE MODERN CLOCK. 



193 



Fig. 62 illustrates the escapement of the Western Clock 
Manufacturing Company for their cheap levers. It has 
hardened steel pallets placed in a mould and the fork cast 
around them, thus insuring exact placing of the pallets, and 
the company claim that they thus secure a detached lever 
escapement with all the advantages of hardened and polished 
pallets at a minimum cost. 

Mr. F. Dauphin, of Cassel, Germany, on page 387 of Der 
Deutsche Uhrmacher Zeitung, 1905, has described a serious 
fault of some of the cheap American alarm clocks in the 




Fig. 62. 

depthings of the escapements and how he remedied it by 
changing the position of the pins. It is to be regretted that 
Mr. Dauphin did not state the measurements of the parts as 
nearly as possible in this article and also give the manu- 
facturer's name, simply to enable others not as skilled as he 
is to do what I would do in such a case ; namely, to return 
it to the jobber and get a new and correct movement in its 
stead free of charge. The American clock manufacturers 
are very liberal in this respect and never hesitate to take 
back a movement that was not correct when it leff the fac- 
tory, even when the customer, in the attempt to correct it, 
has spoiled it ; spoiled or not, it goes to the waste pile any- 
way, when it reaches the factory. I seriously doubt the 
ability of the average watch repairer to correctly change the 
position of the pins as suggested; and to change the center 
of action of the lever is certainly a desperate job. I here- 
vvith give a correct drawing of an escape wheel and lever, 



194 



THE MODERN CLOCK. 



such as are used in the above cited clocks, made from meas- 
urements of the parts of a clock. The drawing is, of 
course, enlarged. The measurements are: Escape wheel, 
actual diameter, i8.ii mm.; original diameter, 17 mm.; 
fever, from pin to pin, outside, 9.3 mm.; distance of cen- 
ters of wheel and lever, lo.o mm. I found that all these 
measurements almost exactly agree with Grossmann's 
tables, and I do not doubt at all that they were taken from 




them. There is only one mistake visible, which is in the 
shape of the escape teeth, and I fail to see why this was 
overlooked by those in charge at the factory: the drazv is 
insufficient. It is only from seven to eight degrees, when 
it should be fifteen degrees. I show this at tooth A, in the 
drawing, where you can see both dotted lines, measuring 
the angle of draw ; line C as it is and line B as it should be. 
Notwithstanding the deficient draw, this escapement will 
work safely as long as the pivot holes are not too large, or 
t\^orn sideways ; but if you want to make it safe you should 
file the locking faces of teeth slightly under ; even if you 



THE MODERN CLOCK. I95 

do not make a model job, you have remedied the fault. 
Make a disk of i8.ii mm. diameter, put it on the arbor of 
the wheel and lay a straight edge from the point of the 
tooth to the center of the disk, so as to see how much it 
needs to be filed away. Even if this undercutting is not 
very true it will go. 

To Measure Wheels with Odd Numbers of Teeth. 
— This is a job that so frequently comes to the watchmaker 
who has to replace wheels or pinions that the following 
simple method should be generally appreciated. It de- 
pends upon the fact that the radius of a circle, R, Fig. 64, 
equals the versed sine E (dotted) plus the cosine B. If 
we stand such a wheel on the points of the teeth, A C, and 
measure it we shall get the length of the line T B only, 
when what we really need is the length of the lines T B E, 
to give us the real diameter for our wheel, and E we find has 
been cut away, so that we cannot measure it. Say it is a 
15-tooth escape wheel, then by standing the old wheel up on 
the anvil of a vertical micrometer, resting it on two of its 
teeth, as shown in Fig. 64, the measuring screw can be 
brought in contact with the tooth diametrically opposite the 
space between the two teeth on the anvil, and a measure- 
ment taken, which will be less than the full diameter by the 
versed sine of 12 degrees (half the angle included between 
two adjoining teeth). By bringing each tooth in succession 
to the top, such a wheel could be measured in fifteen differ- 
ent directions, which would vary slightly, owing to the fact 
that some of the teeth may be bent a little, but the mean 
of these measures should be what the wheel would measure 
were the teeth in their original shape. If a tooth was badly 
bent the three measures in which it was involved could be 
rejected, and the mean of the other twelve measures taken 
as the correct value and found to be, we will say, 0.732 inch. 
Consulting a table of natural sines the cosine of 12 degrees 
is found to be 0.97815, which subtracted from i gives 



196 



THE MODERN CLOCK. 



0.02185 as the versed sine. Multiplying this by 0.36 inch 
(practically one-half of our measured 0.732) to get the 
approximate radius of the wheel, we get 0.008 inch, the 
amount to be added to the micrometer measurement in 
order to get the diameter of the blank. 

At first sight it may appear like a vicious principle that 
we must know the radius of the wheel before we can deter- 




oi. Cjctting the fuU diameter. 



mine the value of the correction in question, but we only 
need to know the radius approximately in order to determine 
the correction very closely, an error of 1-20 inch in the as- 
sumed value of the radius producing an error of only o.ooi 
inch in the value of the correction. 

This method can of course be applied to all wheels and 
pinions to get the size of the blank; with other wheels than 
escape wheels, where the pitch line and the full diameter 
do not coincide, the addendum may be subtracted from the 
full diameter to get the pitch line. 

Cutters for Clock Trains. — In cutting escape wheels 
or others with wnde space between the teeth, it is a matter 



THE MODERN CLOCK. 



97 



of some difficulty with many people to enable them to set 
the cutter properly. 

Mr. E. A. Sweet calls attention to the fact that if a cutter 
be set so that its center touches the circumference of the 
wheel to be cut, said cutter will be in the proper position for 
work. For instance, if an escape wheel is to be cut, it is 
sufficient to set the cutter in such a manner that that portion 
of the cutter forming the bottom of the cut touch the cir- 
cumference of the blank at the center of the cutter. It may 
then be backed off and fed in with the certainty of being 
properly placed. 



CHAPTER XIV. 

PLATES^ PIVOTS AND TIME TRAINS. 

Before going further with the mechanism of our clocks 
we will now consider the means by which the various mem- 
bers are held in their positions, namely, the plates. Like 
most other parts of the clock these have undergone various 
changes. They have been made of wood, iron and brass 
and have varied in shapes and sizes so much that a great 
deal may be told concerning the age of a clock by examining 
the plates. 

Most of the wooden clocks had wooden plates. The 
English and American movements were simply boards of 
oak, maple or pear with the holes drilled and bushed with 
brass tubes — full plates. The Schwarzwald movements 
were generally made with top and bottom boards and 
stanchions, mortised in between them to carry the trains, 
which were always straight-line trains. The rear stanchions 
were glued in position and the front ones fitted friction- 
tight, so that they could be removed in taking down the 
clock. This gave a certain convenience in repairmg, as, for 
instance, the center (time) train could be taken down with- 
out disturbing the hour or quarter trains, or vice versa. 
Various attempts have been made since to retain their con- 
venience with brass plates, but it has always added so much 
to the cost of manufacture that it had to be abandoned. 

The older plates were cast, smoothed and then ham- 
mered to compact the metal. The modern plate is rolled 
much harder and stiflfer and it may consequently be much 
thinner than was formerly necessary. The proper thickness 
of a plate depends entirely upon its use. Where the move- 
ment rests upon a seat board in the case and carries the 



THE MODERN CLOCK. I99 

weight of a heavy penduhim. attached u one of the plates 
they must be made stiff enough to furnish a rigid support 
for the pendulum, and we find them thick, heavy and with 
large pillars, well supported at the corners, so as to be very 
stiff and solid. An example of this may be seen in that 
class of regulators which carry the pendulum on the move- 
ment. Where the pendulum is light the plates may there- 
fore be thin, as the only other reason necessary for thick- 
ness is that they may provide a proper length of bearing for 
the pivots, plus the necessary countersinking to retain the 
oil. 

In heavy machinery it is unusual to provide a length of 
box or journal bearing of more than three times the diam- 
eter of the journal. In most cases a length of twice the 
diameter is more than sufficient; in clock and other light 
work a "square" bearing is enough ; that is one in which 
the length is equal to the diameter. In clocks the pivots are 
of various sizes and so an average must be found. This is 
accomplished by using a plate thick enough to furnish a 
proper bearing for the larger pivots and countersinking the 
pivot holes for the smaller pivots until a square bearing is 
obtained. This countersinking is shaped in such a manner 
as to retain the oil and as more of it is done on the smaller 
and faster moving pivots, where there is the greatest need 
of lubrication, the arrangement works out very nicely, and 
it will be seen that with all the lighter clocks very thin plates 
may be employed while still retaining a proper length of 
bearing in the pivot holes. 

The side shake for pivots should be from .002 to .004 of 
an inch; the latter figure is seldom exceeded except in 
cuckoos and other clocks having exposed w^eights and 
pendulums. Here much greater freedom is necessary as 
the movement is exposed to dust which enters freely at the 
holes for pendulum and weight chains, so that such a clock 
would stop if given the ordinary amount of side shake. 



20O THE MODERN CLOCK. 

We are afraid that many manufacturers of the ordinary 
American clock aim to use as thin brass as possible for 
plates without paying too much attention to the length of 
bearing. If a hole is countersunk it will retain the oil 
when a flat surface will not. The idea of countersinking to 
obtain a shorter bearing will apply better to the fine clocks 
than to the ordinary. In ordinary clocks the pivots must be 
longer than the thickness of the plates for the reason that 
freight is handled so roughly that short pivots will pop out 
of the plates and cause a lot of damage, provided the springs 
are wound when the rough handling occurs. 

It will be seen by reference to Chapter VII (the mechan- 
ical elements of gearing), Figs. 21 to 25, that a wheel and 
pinion are merely a collection of levers adapted to con- 
tinuous work, that the teeth may be regarded as separate 
levers coming into contact with each other in succession; 
this brings up two points. The first is necessarily the rela- 
tive proportions of those levers, as upon these will depend 
the power and speed of the motion produced by their action. 
The second is the shapes and sizes of the ends of our levers 
so that they shall perform their work with as little friction 
and loss of power as possible. 

To Get Center Distances. — As the radii and circum- 
ferences of circles are proportional, it follows that the 
lenoths of our radii are merely the lengths of our levers 
'"^ce Fig, 24), and that the two combined (the radius of 
the wheel, plus that of the pinion) will be the distance at 
which we must pivot our levers (our staffs or arbors of our 
wheels) in order to maintain the desired proportions of 
their revolution. Consequently we can work this rule back- 
wards or forwards. 

For instance if we have a wheel and pinion which must 
work together in the proportion of 7^ to i ; then 7^ -f- i 
=r Sy2; and if we divide the space between centers into 8>4 
spaces we will have one of these spaces for the radius of the 



THE MODERN CLOCK. 20I 

i?ifch circle of the pinion and 7^. for the pitch circle of the 
wheel, Fig. 65. This is independent of the number of teeth 
so long as the proportions be observed ; thus our pinion may 
have eight teeth and the wheel sixty, 60 -f- 8 := 7.5, or 
75 -^ 10 =: 7.5, or 90-f- 12 = 7.5, or any other combination 
of teeth which will make the correct proportion between 
them and the center distances. The reason is that the teeth 
are added to the wheel to prevent slipping, and if they did 
not agree with each other and also with the proportionate 
distance between centers there would be trouble, because 
the desired proportion could not be maintained. 

Now we can also work this rule backwards. Say we 
have a wheel of 80 teeth and the pinion has 10 leaves but 
they do not work together well in the clock. Tried in the 
depthing tool they work smoothly. 80 -^- 10 := 8, conse- 
quentty our center distance must be as 8 and i. 8 -]- i = 95 
the wheel must have 8 parts and the pinion i part of the 
radius of the pitch circle of the wheel. IMeasure carefully 
the diameter of the pitch circle of the v^/heel ; half of that is 
the pitch radius, and nine-eighths of the pitch radius is the 
proper center distance for that wheel and pinion. 

Say we have lost a wheel ; the pinion has 12 teeth and we 
know the arbor should go seven and one-half times to one 
of the missing wheel; we have our center distances estab- 
lished by the pivot holes which are not worn; what size 
should the wheel be and how many teeth should it have ? 
12 X 7-5 = 90, the number of teeth necessary to contain 
the teeth of the pinion 7.5 times. 7.5 -[- i = 8.5, the sum of 
the center distances ; the pitch radius of the pinion can be 
closely measured ; then 7.5 times that is the pitch radius of 
the missing wheel of 90 teeth. Other illustrations with other 
proportions could be added indefinitely but we have, we 
think, said enough to make this point clear. 

Conversion of Numbers. — There is one other point 
which sometimes troubles the student who attempts to fol- 



202 



THE MODERN CLOCK. 



low the expositions of this subject by learned writers and 
that is the fact that a mathematician will take a totally 
difterent set of numbers for his examples, without explain- 
ing why. If you don't know why you get confused and fail 
to follow him. It is done to avoid the use of cumbersome 
fractions. To use a homely illustration: Say we have 
one foot, six inches fo^ cur wheel radius and 4.5 inches for 




Fig. G5. Spacing off center di-tances; c, ce:; cr of wlieel; e, pitch circle; 
d, dedenduni; b, addendum; a, center of pinion. 



our pinion radius. If we turn the foot into inches we have 
18 inches. 18 -f- 4.5 = 4, which is simpler to work with. 
Now the same thing can be done with fractions. In the 
above instance we got rid of our larger unit (the foot) by 
turning it into smaller units (inches) so that we had only 
one kind of units to work with. The same thing can be done 
with fractions ; for instance, in the previous example we 
can get rid of our mixed numbers by turning everything 



THE MODERN CLOCK. 203 

into fractions. Eighteen inches equals 36 halves and 4.5 
equals 9 halves ; then 36 -f- 9 = 4. This is called the con- 
version of numbers and is done to simplify operations. For 
instance in watch work we may find it convenient to turn all 
our figures into thousands of a millimeter, if we are using 
a millimeter gauge. Say we have the proportions of 7.5 to 
I to maintain, then turning all into halves, 7^. X 2 = 15 
and 1X2 = 2. 15 + 2=17 parts for our center distance, 
of which the pitch radius of the pinion takes 2 parts and that 
of the wheel 15. 

The Shapes of the Teeth. — The second part of our 
problem, as stated above, is the shapes of the ends of our 
levers or the teeth of our wheels, and here the first consid- 
eration which strikes us is that the teeth of the wheels ap- 
proach each other until they meet; roll or slide upon each 
other until they pass the line of centers and then are drawn 
apart. A moment's consideration will show that as the 
teeth are longer than the distance between centers and are 
securely held from slipping at their centers, the outer ends 
must either roll or slide after they come in contact and that 
this action will be much more severe while they are being 
driven towards each other than when they are being drawn 
apart after passing the line of centers. This is why the 
engaging friction is more damaging than the disengaging 
friction and it is this butting action which uses up the power 
if our teeth are not properly shaped or the center distances 
not right. Generally speaking this butting causes serious 
loss of power and cutting of the teeth when the pivot holes 
are worn or the pivots cut, so that there is a side shake of 
half the diameter of the pivots, and bushing or closing the 
holes, or new and larger pivots are then necessary. This is 
for common, work. For fine work the center distances 
should be restored long before the wear has reached this 
point. 



204 THE MODERN CLOCK. 

If we take two circular pieces of any material of different 
diameters and arrange them so that each can revolve around 
its center with their edges in contact, then apply power to 
the larger of the two, we find that as it revolves its motion 
i-s imparted to the other, which revolves in the opposite 
direction, and, if there is no slipping between the two sur- 
faces, with a velocity as much greater than that of the larger 
disc as its diameter is exceeded by that of the larger one. 
We have, then, an illustration of the action of a wheel and 
pinion as used in timepieces and other mechanisms. It 
would be impossible, however, to prevent slipping of these 
smooth surfaces on each other so that power (or motion) 
would be transmitted by them very irregularly. They simply 
represent the "pitch" circles or circles of contact of these 
two mobiles. If now we divide these two discs into teeth 
so spaced that the teeth of one will pass freely into the 
spaces of the other and add such an amount to the diameter 
of the larger that the points of its teeth extend inside the 
pitch circle of the smaller, a distance equal to about i^ 
times the width of one of its teeth, and to the smaller so 
that its teeth extend inside the larger one-half the width of 
a tooth, the ends of the teeth being rounded so as not to 
catch on each other and the centers of revolution being kept 
the same distance apart, on applying power to the larger of 
the two it will be set in motion and this motion will be im- 
parted to the smaller one. Both will continue to move with 
the same relative velocity as long as sufficient power is 
applied. Other pairs of mobiles may be added to these to 
infinity, each addition requiring the application of increased 
power to keep it in motion. 

These pairs of mobiles as applied to the construction of 
timepieces are usually very unequal in size and the larger 
is designated as a "wheel" while the smaller, if having less 
than 20 teeth, is called a "pinion" and its teeth "leaves." 
Now while we have established the principle of a train of 
wheels as used in various mechanisms, our gearing is very 



THE MODERN CLOCK. 



205 



defective, for while continuous motion may be transmitted 
through such a train, we will find that to do so requires 
the application of an impelling force far in excess of what 
should be required to overcome the inertia of the mobiles, 
and the amount of friction unavoidable in a mechanism 
where some of the parts move in contact with others. 

This excess of power is used in overcoming a friction 
caused by improperly shaped teeth, or when formed thus the 
teeth of the wheel come in contact with those of the pinion 
and begin driving at a point in front of what is known as the 
"line of centers," i. e., a line drawn through the centers of 
revolution of both mobiles, and as their motion continues the 
driven tooth slides on the one impelling it toward the center 
of the wheel. When this line is reached the action is re- 
versed and the point of the driving tooth begins sliding on 
the pinion leaf in a direction away from the center of the 
pinion, which action is continued until a point is reached 
where the straight face of the leaf is on a line tangential to 
the circumference of the wheel at the point of the tooth. It 
then slips off the tooth, and the driving is taken up on an- 
other leaf by the next succeeding tooth. The sliding action 
which takes place in front of the line of centers is called 
"engaging," that after this line has been passed "disengag- 
ing" friction. 

Now we know that in the construction of timepieces, fric- 
tion and excessive motive power are two of the most potent 
factors in producmg disturbances in the rate, and that, while 
som.e friction is unavoidable in any mechanism, that which we 
have just described may be almost entirely done away with. 
Let us examine carefully the action of a wheel and pinion, 
and we will see that only that part of the wheel tooth is used, 
which is outside the pitch circle, while the portion of the 
pinion leaf on which it acts is the straight face lying inside 
this circle, therefore it is to giving a correct shape to these 
parts we must devote our attention. If we form our pinion 
leaves so that the portion of the leaf inside the pitch circle 



206 



THE MODERN CLOCK, 



is a straight line pointing to the center, and give that por- 
tion of the wheel tooth lying outside the pitch circle (called 
the addenda, or ogive of the tooth) such a degree of curva- 
ture that during its entire action the straight face of the 
leaf will form a tangent to that point of the curve which it 



Showing that a hypocycloid of 



rcle is a straight line. 




Generating an epicycloid curve for a cut pinion. D, generating circle. 
Uotterl line epicycloid curve. Note how the shape varies with the 
thickness of the tooth. 

touches, no sliding action whatever will take place after the 
line of centers is passed, and if our pinion has ten or more 
leaves, the "addenda" of the wheel is of proper height, and 
the leaves of the pinion arc net too thick, there will be no 
contact in front of the I'ne of centers. With such a depth 
the only friction would be from a slight adhesion of the 
surfaces in contact, a factor too small to be taken into 
consideration. 



THE MODERN CLOCK. 



207 



Here, then, we have an ideal depth. How shall we obtain 
the same results in practice? It is comparatively an easy 
matter to so shape our cutters that the straight faces of our 
pinion leaves will be straight lines pointing to the center, 
but to secure just the proper curve for the addenda of our 
wheel teeth requires rather a more complicated manipula- 
tion. This curve does not form a segment of a circle, for it 
has no two radii of equal length, and if continued would 
form, not a circle, but a spiral. To generate this curve, we 
will cut from cardboard, wood, or sheet metal, a segment of 
a circle having a radius equal to that of our zvheel, on the 
pitch circle, and a smaller circle whose diameter is equal to 
the radius of the pinion, on the pitch circle. To the edge of 
the small circle we will attach a pencil or metal point so that 
it will trace a fine mark. Now we lay our segment flat on a 
piece of drawing paper, or sheet metal and cause the small 
circle to revolve around its edge without slipping. We find 
that the point in the edge of the small circle has traced a 
series of curves around the edge of the segment. 

These curves are called *V.p:cycloids," and have the pe- 
culiar property that if a line be drawn through the generat- 
ing point and the point of contact of the two circles, this will 
always be at right angles to a tangent of the curve at its 
[)oint of intersection. It is this property to which it owes its 
value as a shape for the acting surface of a wheel tooth, 
for it is owing to this that a tooth whose acting surface is 
bounded by such a curve can impel a pinion leaf through 
the entire lead with little sliding action between the two 
surfaces. This, then, is the curve on which we will form 
the addenda of our wheel teeth. 

In Fig. 66, the wheel has a radius of fifteen inches and the 
pinion a radius of one and one-half, and these two measure- 
ments are to be added together to find the distance apart 
of the two wheels; 16.5 inches is then the distance that the 
centers of revolution are apart of the wheels. Now, the teeth 
and leaves jointly act on one another to maintain a sure and 
equable relative revolution of the pair. 



20^ THE MODERN CLOCK. 

In Fig. 66, the pinion has its leaves radial to the center, 
inside of the pitch line D, and the ends of the leaves, or those 
parts outside of the pitch line, are a half circle, and serve no 
purpose until the depthings are changed by wear, as they 
never come in contact with the wheel ; the wheel teeth only 
touch the radial part of the pinion and that occurs wholly 
within the pitch line. So in all pinions above lo leaves in 
number the addendum or curve is a thing of no moment, 
except as it may be too large or too long. In many large 
pieces of machinery the pinions, or small driven wheels, 
have no addendum or extension beyond their pitch diameter 
and they serve every end just as well. In watches there is 
so much space or shake allowed between the teeth and 
pinions that the end of a leaf becomes a necessitv to guard 
against the pinion's recoiling out of time and striking its 
sharp corner against the wheel teeth and so marring or 
cutting them. In a similar pair of wheels in machinery there 
are very close fits used and the shake between teeth is very 
slight and does not allow of recoil, butting, or "running out 
of time." 

Running out of time is the sudden stopping and setting 
back of a pinion against the opposite tooth from the one 
just in contact or propelling. This, with pinions of sup- 
pressed ends, is a fault and it is averted by maintaining the 
ends. 

The wheel tooth drives the pinion by coming in contact 
with the straight flank of the leaf at the line of centers, that 
is a line drawn through the centers of the two wheels ; cen- 
ters of revolution. 

The curve or end of the wheel tooth outside of the pitch 
line is the only part of the tooth that ever touches the pinion 
and it is the part under friction from pressure and slipping. 
At the first point of contact the tooth drives the pinion with 
the greatest force, as it is then using the shortest leverage it 
has and is pressing on the longest lever of the leaf. As 
this action proceeds, the tooth is acted on by the pinion leaf 



THE MODERN CLOCK. 



209 



farther out on the curve of the wheel tooth, thus length- 
ening the lever of the wheel and at the same time the tooth 
thus acts nearer to the center of the pinion by touching 
the leaf nearer its center of revolution. 

By these joint actions' it will^ appear that the wheel first 
drives with the greatest force and then as its own leverage 
lengthens and its force consequently decreases, it acts on a 
shorter leverage of the pinion, as the end of a tooth, is nearer 
to the center of the pinion, or on the shortest pinion lever- 
age, just as the tooth is about ceasing to act. 

The action is thus shown from the above to be a variable 
one, which starts with a maximum of force and ends with a 
minimum. Practically the variable force in a train is not 
recognized in the escapement, as the other wheels and pin- 
ions making up the train are also in the same relations of 
maximum and minimum forces at the same time, and thus 
this theoretical and virtual variability of train force is to a 
great extent neutralized at the active or escaping end of the 
movement. 

There is another action between the tooth and leaf that is 
not easy to explain without somewhat elaborate sketches of 
the acting parts, and as this is not consistent with such an 
article, we may dismiss it, and merely state that it is the 
one of maintaining the relative angular velocities of the two 
wheels at all times during their joint revolutions. 

In Fig. 66 will be seen the teeth of the wheel, their 
heights, widths and spacing, and the epicycloidal curves. 
Also the same features of the pinion's construction. The 
curve on the end of the wheel teeth is the only curve in 
action during the rotation between wheel and pinion. Each 
flank (both teeth and leaves) is a straight line to the 
center of each. A tooth is composed of two members — the 
pillar or body of the tooth inside of the pitch line and the 
cvcloid or curve, wholly outside of this line. The pinion 
also has two members, the radial flank wholly inside of the 
pitch line, and its addendum or circle outside of this line. 



2IO 



THE MODERN CI.OCK, 




A' 




yyiteelolf^ff 



I .66 



THE MODERN CLOCK. 211 

In Fig. 66 will be seen a tooth on the line of centers A B, 
just coming in action against the pinion's flank and also one 
just ceasing action. It will be seen that the tooth just enter- 
ing is in contact at the joint pitches, or radii, of the two 
wheels, and that when the tooth has run its course and 
ceased to act, that it will be represented by tooth 2, Then 
the exit contact will be at the dotted line o o. From this 
may be seen just how far the tooth has, in its excursion, 
shoved along the leaf of the pinion and by the distance the 
line o o, is from the wheel's pitch line G, at this tooth. No. 2, 
is shown the extent of contact of the wheel tooth. By these 
dotted lines, then, it may be seen that the tooth has been 
under friction for nearly its whole curve's length, while the 
pinion's flank will have been under friction contact for less 
than half this distance. In brief, the tooth has moved about 
80-100 o'f its curved surface along the straight flank .35 of 
the surface of the pinion leaf. From this relative frictional 
surface may be seen the reason why a pinion is apt to be 
pitted by the wheel teeth and cut away. In any case it 
shows the relation between the two friction surfaces. In 
part a wheel tooth rolls as well as slides along the leaf, but 
whatever rolling there may be, the pinion is also equally 
favored by the same action, which leaves the proportions of 
individual friction still the same. 

In Fig. 66 may be seen the spaces of the teeth and pinion. 
The teeth are apart, equal to their own width and the depths 
of the spaces are the same measurement of their width — that 
is, the tooth (inside of the pitch line) is a pillar as wide as it 
is high and a space between two teeth is of like proportions 
and extent of surface. The depth of a space between two 
teeth is only for clearance and may be made much less, as 
may be seen by the pinion leaf, as the end of the circle does 
not come half way to the bottom of a space. 

The dotted line, o o, shows the point at which the tooth 
comes out of action and the pointed end outside of this line 
might be cut off without interfering with any function of 



212 THE MODERN CLOCK. 

the tooth. They generally are rounded off in common clock 
work. 

The pinion is 3 inches diameter and is divided into twelve 
spaces and twelve leaves; each leaf is two-fifths of the 
width of a space and tooth. That is one-twelfth of the cir- 
cumference of the pinion is divided into five equal parts and 
the leaf occupies two and a space three of these parts. The 
space must be greater than the width of a leaf, or the end of 
a leaf w^ould come in contact with a tooth before the line 
of centers and cause a jamming and butting action. Also 
the space is needed for dirt clearance. As watch trains 
actuated by a spring do not have any reserve force there 
must be allowance made for obstructions between the teeth 
of a train and so a large latitude is allowed in this respect, 
more than in any machinery of large caliber. As will be 
seen by Fig. 66, the spans between the leaves are deep, much 
more so than is really necessary, and a space at O C shows 
the bottom of a space, cut on a circle which strengthens a 
leaf at its root and is the best practice. 

Having determined the form of our curve, our next step 
will be to get the proper proportions. Saunier recommends 
that in all cases tooth and space should be of equal width, 
but a more modern practice is to make the space slightly 
wider, say one-tenth where the curve is epicycloidal. When 
the teeth are cut with the ordinary Swiss cutters, which, of 
course, cannot be epicycloidal, it is best to make the spaces 
one-seventh wider than the tooth. This proportion will be 
correct except in the case of a ten-leaf pinion, when, if we 
w4sh to be sure the driving will begin on the line of centers, 
the teeth must be as wide as the spaces ; but in this case 
the pinion leaf is made proportionately thinner, so that the 
requisite freedom is thus obtained. 

The height of the addenda of the wheel teeth above the 
pitch circle is usually given as one and one-eighth times the 
width of a tooth. While this is approximately correct, it is 
not entirelv so, for the reason that as we use a circle whose 



THE MODERN CLOCK. 213 

diameter is equal to the pitch radius of the pinion for gen- 
erating the curve, the height of the addenda would be differ- 
ent on the same wheel for each different numbered pinion. 
So that if a wheel of 60 were cut to drive a pinion of 8, the 
curve of this tooth would be found too flat if used to drive 
a pinion of 10. Now, since the pitch diameter of the pinion 
is to the pitch diameter of the wheel as the number of leaves 
in the pinion are to the number of teeth in the wheel, in 
order to secure perfect teeth: we must adopt for the height 
of the addenda a certain proportion of the radius or diameter 
of the pinion it is to drive, this proportion depending on the 
number of leaves in the pinion. 

A careful study of the experiments on this subject with 
models of depths constructed on a large scale, shows that 
the proportions given below com.e the nearest to perfection. 

When the pinion has six leaves the spaces should be twice 
the width of the leaves and the depth of the space a little 
more than one-half the total radius of the pinion. The ad- 
denda of the pinion should be rounded, and should extend 
outside the pitch circle a distance equal to about one-half 
the width of a leaf. The addenda of the wheel teeth should 
be epicycloidal in form and should extend outside the pitch 
circle a distance equal to five-twelfths of the pitch radius 
of the pinion. 

With these proportions, the tooth will begin driving when 
one-half the thicknesi- of a leaf is in front of the line of 
centers, and there will be engaging friction from this point 
until the line of centers is reached. 

This cannot be avoided with low-numbered pinions with- 
out introducing a train of evils more productive of faulty 
action than the one we are trying to overcome. There will 
be no disengaging friction. 

When a pinion of seven is used, the spaces of the pinion 
should be twice the width of the leaves, and the depth of a 
space about three-fifths of the total radius of the pinion. 
The addenda of the pinion leaves should be rounded, and 



214 THE MODERN CLOCK. 

should extend outside the pitch circle about one-half, the 
width of a leaf. The addenda of the wheel teeth should be 
epicycloidal, and the height of each tooth above the pitch 
circle equal to two-fiflhs of the pitch radius of the pinion. 
'There is less engaging friction when a pinion of seven is 
used than with one of six, as the driving does not begin 
until two-thirds of the leaf is past the line of centers. There 
is no disengaging friction. 

With an eight-leaf pinion the space should be twice as 
wide as the leaf, and the depth of a space about one-half the 
total radius of the pinion. The addenda of the pinion leaves 
should be rounded and about one-half the width of a leaf 
outside the pitch circle. The addenda of the wheel teeth 
should be epicycloidal, and the height of each tooth above 
the pitch circle equal to seven-twentieths of the pitch radius 
of the pinion. 

With a pinion of eight there is still less engaging friction 
than with one of seven, as three-quarters of the width of a 
leaf is past the line of centers when the driving begins. As 
there is no disengaging friction, a pinion of this number 
makes a very satisfactory depth. 

A pinion with nine leaves is sometimes, though seldom,, 
used. It should have the spaces twice the width of the 
leaves, and the depth of a space one-half the total radius. 
The addenda should be rounded, and its height above the 
pitch circle equal to one-half the width of the leaf. The 
addenda of the wheel teeth should be epicycloidal, and the 
height of each tooth above the pitch circle equal to three- 
sevenths of the total radius of the pinion. With this pinion 
the driving begins very near the line of centers, only about 
one-fifth of the width of a leaf being in front of the line. 

A pinion of ten leaves is the lowest number with which 
we can entirely eliminate engaging friction, and to do so in 
this case the proper proportions must be rigidly adhered to. 
The spaces on the pinion must be a little more than twice 
as w^de as a leaf; a leaf and space will occupy 36° of arc; 



THE MODERN CLOCK. 215 

of this 11° should be taken for the leaf and 25° for the 
space. The addenda should be rounded and should extend 
about half the width of a leaf outside the pitch circle. The 
depth of a space should be equal to about one-half the total 
radius. For the wheel, the teeth should be equal in width 
to the spaces, the addenda epicycloidal in form, and the 
"height of each tooth above the pitch circle, equal to two- 
fifths the pitch radius of the pinion. 

A pinion having eleven leaves would give a better depth, 
theoretically, than one of ten, as the leaves need not be made 
quite so thin to ensure its not coming in action in front of 
the line of centers. It is seldom seen in watch or clock 
work, but if needed the same proportions should be used 
as with one of ten, except that the leaves may be made a 
little thicker in proportion to the spaces. 

A pinion having twelve leaves is the lowest number with 
which we can secure a theoretically perfect action, without 
sacrificing the strength of the leaves or the requisite freedom 
in the depths. In this pinion, the leaf should be to the space 
as two to three, that is, we divide the arc of the circum- 
ference needed for a leaf and space into five equal parts, 
and take two of these parts for the leaf, and three for the 
space; depth of the space should be about one-half the 
total radius. The addenda of the wheel teeth should be 
epicycloidal, and the height of each tooth above the pitch 
line equal to two-sevenths the pitch radius of the pinion. 

As the number of leaves is increased up to twenty, the 
width of the space should be decreased, until when this 
number is reached the space should be one-seventh wider 
than the leaf. As these numbers are used chiefly for wind- 
ing wheels in watches, where considerable strength is re- 
quired, the bottoms of the spaces of both mobiles should be 
rounded. 

Circular Pitch. Diametral Pitch. — In large ma- 
chinery it is usual to take the circumference and divide by 
the number of teeth ; this is called the circular pitch, or dis- 



2l6 THE MODERN CLOCK. 

tance from point to point of the teeth, and is useful for de- 
scribing teeth to be cut out as patterns for casting. 

But for all small wheels it is more convenient to take the 
diameter and divide by the number of teeth. This is called 
the diametral pitch, and when the diameter of a wheel or 
pinion which is intended to work into it is desired, such 
diameter bears the same ratio or proportion as the number 
required. Both diameters are for their pitch circles. As 
the teeth of each wheel project from the pitch circle and 
enter into the other, an addition of corresponding amount 
is made to each wheel ; this is called the addendum. As the 
size of a tooth of the wheel and of a tooth of the pinion are 
the same, the amount of the addendum is equal for both ; 
consequently the outside diameter of the smaller wheel or 
pinion will be greater than the arithmetical proportion be- 
tween the pitch circles. As the diameters are measured pre- 
sumably in inches or parts of an inch, the number of a 
wheel of given size is divided by the diameter, which gives 
the number of teeth to each inch of diameter, and is called 
the diametral pitch. In all newly-designed machinery a 
whole number is used and the sizes of the wheels calculated 
accordingly, but when, as in repairing, a wheel of any size 
has any number of teeth, the diametral number may have an 
additional fraction, whicli docs not affect the principle but 
gives a little more trouble in calculation. Take for ex- 
ample a clock main wheel and center pinion : Assuming 
the wheel to be exactly three inches in diameter at the pitch 
line, and to have ninety-six teeth, the result will be 96-1-3 
= ^2, or 32 teeth to each inch of diameter, and would be 
called ^2 pitch. A pinion of 8 to gear with this wheel 
would have a diameter at the pitch line of 8 of these thirty- 
seconds of an inch or 8-32 of an inch. But possibly the 
wheel might not be of such an easily manageable size. It 
might, say, be 3.25 inches, in which case, 96 being the num- 
ber of the wheel and 8 of the pinion, the ratio is 8-96 or 1-12, 
so 1-12 of 3.25 := 0.270, the pitch diameter of the pinion. 



THE MODERN CLOCK. 217 

These two examples are given to indicate alternative meth- 
ods, the most convenient of which may be used. After 
arriving at the true pitch diameters the matter of the adden- 
dum arises, and it is for this that the diametral number is 
specially useful, as in every case when figuring by this 
system, whatever the number of a wheel or pinion, two of 
the pitch numbers are to be added. Thus with the 32 pitch, 
the outside diameter of the wheel will be 3 in. -f- 2-32, and 
if the pinion 8-32 -}- 2-32 = 10-32. With the other method 
the same exactness is more difficult of attainment, but for 
practical purposes it will be near enough if we use 2-30 of 
an inch for the addendum, when the result will be 3.25 -f- 
2-30 or 33/4 -4- 2-30 = 31-3 in. nearly and the pinion 0.270 
-f- 2-30 = 0.270 + .0666 = 0.3366 ; or to v/ork by 1-3 of 
an inch is near enough, giving the outside diameter of the 
pinion a small amount less than the theoretical, which is 
always advisable for pinions which are to be driven. 

We represent by Figs. 67 to 71 a wheel of sixty teeth 
gearing with a pinion of six leaves. The wheel, whose 
pitch diameter is represented by the line mm is the same ih 
each figure. The pinion, which has for its pitch diameter 
the line kk, is in Fig. 67, of a size proportioned to that of 
the wheel, and its center is placed at the proper distance; 
that is to say, the two pitch diameters are tangential. 

In Fig. 68 the same pinion, of the proper size, has its 
center too far off ; the depthing is too shallow. In Fig. 69 
it is too deep. Figs. 70 and 71 represent gearing in which 
the pitch circles are in contact, as the theory requires, but 
the size of the pinions is incorrect. If the wheels and pinion 
actuated each other by simple contact the velocity of the 
pinion with reference to that of the wheel would not be 
absolutely the same; but the ratio of the teeth being the 
same, the same ratio of motion obtains in practice, and 
there is necessarily bad w^orking of the teeth with the 
leaves. 



2l8 THE MODERN CLOCK. 

We will observe what passes in each of these cases, and 
refer to the suitable remedies for obtaining a passable 
depthing and a comparatively good rate, without the neces- 
sity of repairs at a cost out of all proportion with the value 
of the article repaired. 




^ \ \ J ^ ^ ' ^ — ^ '^ i'L A' > / ^"^ 



Fig. 67 

Fig. 6y represents gearing of which the wheel and pinion 
are well proportioned and at the proper distance from each 
other. Its movement is smooth, but it has little drop or 
none at all. By examining the teeth h, h', of the wheel, it 
is seen that they are larger than the interval between them. 
With a cutter FF, introduced between the teeth, they are 
reduced at d, d', which gives the necessary drop without 
changing the functions, since the pitch circles mm and kk 
have not been modified. The drop, the play between the 
tooth d' and the leaf a, is sufficiently increased for the work- 
ing of the gearing with safety. 

We have the same pair in Fig. 68, but here their pitch 
circles do not touch ; the depthing is too shallow. The 
drop is too great and butting is produced between the tooth 
h and the leaf r, which can be readily felt. The remedy is 
in changing the center distance, by closing the holes, if 



THE MODERN CLOCK. 



219 



worn, or moving one nearer the other. But in an ordinary 
clock this wheel may be replaced with a larger one, whose 
pitch circle reaches to e. The proportions of the pair are 
modified, but not sufficiently to produce inconvenience. 

It may also answer to stretch the wheel, if it is thick 
enough to be sufficiently increased in size. A cutte*^ should 
then be selected for rounding up which will allow the full 







Fig. 



width to the tooth as at p; but if it is not possible to en- 
large the wheel enough, a little of the width of the teeth 
may be taken off, as is seen at h, which will diminish the 
butting with the leaf r. 

Too great depthing. Fig. 69, can generally be recognized 
by the lack of drop. When the teeth of the wheel are nar- 
row, the drop may appear to be sufficient. When the train 
is put in action the depthing that is too great produces 
scratching or butting and the 'scape wheel trembles. This 
results from the fact that the points of the teeth of the 
wheel touch the core of the pinion and cause it to butt 
against the leaf following the one engaged, as is visible at 
r in Fig. 69. It should be noticed that in this figure the 
pitch circles mm and kk overlap each other, instead of being 
tangential. 



220 



THE MODERN CLOCK 




Fiir. CO 



nc 




^^ 



Fig. TO 



THE MODERN CLOCK. 221 

To correct this gearing, the cutter should act only on the 
addenda of the teeth of the wheel, so as to diminish them 
and bring the pitch circle mm to n. The dots in the teeth 
d, d', show the corrected gearing. It is seen that there will 
be, after this change, the necessary drop, and that the end 
of the tooth d' will not touch the leaf r. 

In the two preceding cases we have considered wheels 
and pinions of accurate proportion, and the defects of the 
gearing proceeding from the wrong center distances. We 
will not speak of the gearing in which the pinion is too 
small. The only theoretic remedy in this case, as in that 
of too large a pinion, is to replace the defective piece; but 
in practice, when time and money are to be saved, advan- 
tage must be taken, one w^ay or another, of what is in 
existence. 

The buzzing produced when the train runs in a gearing 
with top small a pinion proceeds from the fact that each 
tooth has a slight drop before engaging with the corre- 
sponding leaf. If we examine Fig. 70, it will be easy to 
see how this drop is produced. The wheel revolving in the 
direction indicated by the arrow, it can be seen that when 
the tooth h leaves the leaf r, the following tooth, p, does not 
engage with the corresponding leaf, s ; this tooth will there- 
fore have some drop before reaching the leaf. A friction 
may even be produced at the end or addendum of the tooth 
p against the following leaf v. 

To obtain a fair depthing without replacing the pinion, 
the wheels can be passed to the rounding up machine, hav- 
ing a cutter which will take off only the points of the teeth, 
as is indicated in the figure ; the result may be observed by 
the dotted lines. The tooth h being shorter, it will leave 
the leaf r of the pinion when the latter is in the dotted 
position; that is to say, a little sooner. At this moment 
the tooth p is in contact with the leaf s, and there is no risk 
of friction against the leaf v. Care must be taken to touch 
only the addendum of the tooth so as not to weaken the 



222 



THE MODERN CLOCK. 



teeth. The circumference i will be that of a pinion of ac- 
curate size, and if the pinion is replaced, it will be necessary 
to diminish the wheel so that its pitch circle shall be tan- 
gential with i. 

- With too small a pinion a passable gearing can generally 
be produced. In any case stoppage can be prevented. This 
is not so easy when the pinion is too large. In Fig. 71, the 




Fig. 71 

pinion has as its pitch circle the line k, inscead of i, which 
would be nearer the size with reference to that of the wheel. 
This is purposely drawn a little small for clearness of illus- 
tration. The essential defect of such a gearing can be seen ; 
the butting produced between the tooth p and the leaf s will 
cause stoppage. How shall this defect be corrected without 
replacing the pinion? 

To remedy the butting as far as possible, some watch- 
makers slope the teeth of the wheel by decentering the cut- 
ter on the rounding-up machine. At FF the cutter is seen 
working between the teeth d and d'. It is evident that 
when the wheel becomes smaller it is necessary to stretch it 
out, and to make use of the cutter afterwards. However, 



THE MODERN CLOCK. 



223 



the most rational method is to leave the teeth straight, and 
to give them the slenderest form possible, after having en- 
larged the wheel or having replaced it with another. The 
motive force of the wheel being sufficiently weak, the size 
of the teeth may be reduced without fear. The essential 
thing is to suppress the butting. Success will be the easiest 
when the teeth are thinner. 

In conclusion, we recommend verification of all sus- 
pected gearings by the depthing tool, which is easier and 
surer than by the clock itself. One can see better by the 
tool the working of the teeth with the leaves, and can form 
a better idea of the defect to be corrected. With the aid of 
the illustrations that have been given it can be readily 
noticed whether the depthing is too deep or too shallow, or 
the pinion too large or too small. 

The defects mentioned are of less consequence in a pinion 
of seven leaves, and they are corrected more readily. With 
pinions of higher numbers the depthings will be smoother, 
provided sufficient care has been taken in the choice of the 
rounding-up cutters. 

Rounding-Up Wheels. — It is frequently observed that 
young watchmakers, and (regretfully be it said) some of 
the older and more experienced ones, are rather careless 
when fitting wheels on pinions. In many cases the wheel is 
simply held in the fingers and the hole opened with a broach, 
and in doing this no special care is taken to keep the fiole 
truly central and of correct size to fit the pinion snugly, and 
should it be opened a little too large it is riveted on the 
pinion whether concentric or not. Many suppose the round- 
ing-up tool will then make it correct without further trouble 
and without sufficient thought of the irregularities ensuing 
when using the tool. 

To make the subject perfectly clear the subjoined but 
rather exaggerated sketch is shown, Fig. ^2. Of course, it 
is seldom required to round-up a wheel of twelve teeth, and 



224 "^^^ MODERN CLOCK. 

the eccentricity of the wheel would be hardly as great as 
shown; nevertheless, assuming such a case to occur the 
drawing will exactly indicate the imperfections arising from 
the use of a rounding-up tool. 

' Presuming from the drawing that the wheel, as shown by 
dotted lines, had originally been cut with its center at m, 
but through careless fitting had been placed on the pinion at 
o, and consequently is very much out of round when tested 
in the calipers, and to correct this defect it is put in the 

7 






6 




il '-'': 



rounding-up tool. The cutter commences to remove the 
metal from tooth y, it being the highest, next the neighbor- 
mg teeth 6 and 8, then 5 and 9, and so on until tooth i comes 
in contact with the cutter. The wheel is now round. But 
how about the size of the teeth and the pitch ? The result of 
the action of the cutter is shown by the sectionally lined 
wheel. J\Iany will ask how such a result is possible, as the 
cutter has acted equally upon all the teeth. Nevertheless, a 
little study of the action of the rounding-up cutter will soon 
make it plain why such faults arise. Naturally the spaces 
between the teeth through the action of the cutter will be 
equal, but as the cutter is compelled to remove considerable 



THE MODERN CLOCK. 22^ 

metal from the point of greatest eccentricity, i. e., at tooth 7 
and the adjoining teeth, to make the wheel round, and the 
pitch circle being smaller the teeth become thinner, as the 
space between the teeth remains the same. At tooth i no 
metal was removed, consequently it remains in its original 
condition. The pitch from each side of tooth i becomes less 
and less to tooth 7, and the teeth thinner, and the thickest 
tooth is always found opposite the thinnest. 

In the case of a wheel having a large number of teeth and 
the eccentricity of which is small, such faults as described 
cannot be readilv seen, from the fact that there are many 
teeth and the slight change in each is so gradual that the 
only way to detect the difference is by comparing opposite 
teeth. And this eccentricity becomes a serious matter when 
there are but few teeth, as before explained, especially when 
reducing an escape wheel. The only proper course to 
pursue is to cement the wheel on a chuck, by putting it in a 
step chuck or in any suitable manner so that it can be trued 
by its periphery and then opening the hole truly. This 
method is followed by all expert workmen. 

A closer examination of the drawing teaches us that an 
eccentric wheel with pointed teeth — as cycloidal teeth are 
mostly left in this condition when placed in the rounding-up 
tool, will not be made round, because when the cutter has 
just pointed the correct tooth (tooth No. i in the drawing) 
it will necessarily shorten the thinner teeth, Nos. 6, 7, 8, i. e., 
the pitch circle v/ill be smaller in diameter. We can, there- 
fore, understand why the rounding-up tool does not make 
the wheel round. 

As we have before observed, when rounding-up an eccen- 
trically riveted wheel, the thickest tooth is always opposite 
the thinnest, but with a wheel which has been stretched the 
case is somewhat different. Most wheels when stretched 
become angular, as the arcs between the arms move outward 
in a greater or less degree, which can be improved to some 
extent by carefully hammering the wheel near the arms, but 



226 



THE MODERN CLOCK. 



some inequalities will still remain. In stretching a wheel 
with five arms we therefore have five high and as many de- 
pressed parts on its periphery. If this wheel is now rounded- 
up the five high parts will contain thinner teeth than the 
depressed portions. Notwithstanding that the stretching of 
wheels, though objectionable, is often unavoidable on ac- 
count of the low price of repairs, it certainly ought not to be 
overdone. Before placing the wheel in the rounding-up tool 
it should be tested in the calipers and the low places care- 
fully stretched so that the wheel is as nearly round as can be 
made before the cutter acts upon it. 

It is hardly necessary to mention that the rounding-up tool 
will not equalize the teeth of a badly cut wheel, and further 
should there be a burr on some of the teeth which has not 
been removed, the action of the guide and cutter in entering 
a space will not move the wheel the same distance at each 
tooth, thus producing thick and thin teeth. From what has 
been said it would be wrong to conclude that the rounding- 
up tool is a useless one ; on the contrary, it is a practical and 
indispensable tool, but to render good service it must be cor- 
rectly used. 

In the use of the rounding-up tool the following rules are 
to be observed : 

1. In a new wheel enlarge the hole after truing the wheel 
from the outside and stake it concentrically on its pinion. 

2. In a rivetted but untrue wheel, stretch the deeper por- 
tions until it runs true, then reduce it in the rounding-up 
tool. The better method is to remove the wheel from its 
pinion, bush the hole, open concentrically with the outside 
and rivet, as previously mentioned in a preceding paragraph. 
But if the old riveting cannot be turned so that it can be used 
again it is best to turn it entirely away, making the pinion 
shaft conical towards the pivot, and after having bushed the 
wheel, drill a hole the proper size and drive it on the pinion. 
The wheel will be then just as secure as when rivetted, as 
in doing the latter the wheel is often distorted. With a very 



THE MODERN CLOCK. 227 

thin wheel allow the bush to project somewhat, so that it 
has a secure hold on the pinion shaft and cannot work 
loose. 

3. Should there be a feather edge on the teeth, this 
should be removed with a scratch brush before rounding it 
up, but if for some reason this cannot well be done, then 
place the wheel upon the rest with the feather edge nearest 
the latter so that the cutter does not come immediately in 
contact with it. If the feather edge is only on one side of 
the tooth — which is often the case — place the wheel in the 
tool so that the guide will turn it from the opposite side of 
the tooth ; the guide will now move the wheel the correct dis- 
tance for the cutter to act uniformly. Of course, in every 
case the guide, cutter and wheel, .must be in correct position 
to ensure good work. 

4. To obtain a smooth surface on the face of the teeth 
a high cutter speed is required, and for this reason it is ad- 
vantageous to drive the cutter spindle by a foot wheel. 

Making Single Pinions. — There are two ways of mak- 
ing clock pinions ; one is to take a solid piece of steel of the 
length and diameter needed and turn away the surplus ma- 
terial to leave the arbor and the pinion head of suitable di- 
mensions ; the other way is to make the head and the arbor 
of separate pieces; the head drilled and fixed on the arbor 
by friction. The latter plan saves a lot of work, and the cut- 
ting of the teeth may be easier. One method is as good as 
the other, as the force on the train is very slight and the 
pinion head may be driven so tightly on the arbor as to be 
perfectly safe without any other fastening, provided the 
arbor is given a very small taper, .001 inch in four inches. 
The steel for the arbor may be chosen of such a size as to re- 
quire very little turning, and hardened and tempered to a 
full or pale blue before commencing turning it, but the piece 
intended for the pinion head must be thoroughly annealed, 
or it may be found impossible to cut the teeth without de- 



228 THE MODERN CLOCK. 

stroying a cutter, which, being valuable, is worth taking 
care of. 

Pinions for ordinary work are not hardened; as they are 
left soft by the manufacturers it would be nonsense for the 
repairer to put in one hardened pinion in a clock where all 
the others were soft. Pinions on fine work are hardened. 
Turning is done between centers to insure truth. 

Before commencing work on the pinion blanks it is ad- 
visable to try the cutters on brass rod, turned to the exact 
size, and if the rod is soft enough it will be found that the 
cutter will make the spaces before it is hardened, which is 
a very important advantage, admitting of correction in the 
form of the cutter if required ; only two or three teeth need 
be cut in the brass to enable one to see if they are suitable, 
and if foimd so, or after an alteration of the cutter, the en- 
tire number may be cut round and the brass pinion made use 
of for testing its accuracy as to size and shape by laying the 
wheel along with it on a flat plate, having studs placed at 
the proper center distance. By this means the utmost re- 
finement may be made in the diameter of the brass pinion, 
which will then serve as a gauge for the diameter of the 
steel pinions, it being recollected, as mentioned in a previous 
paragraph, that a slight variation in the diameter of a pinion 
may be made to counterbalance a slight deviation from 
mathematical accuracy in the form of the wheel-teeth, such 
as is liable to occur owing to the smallness of the teeth mak- 
ing it impracticable to actually draw the true curves, the 
only way of getting them being to draw them to an enlarged 
scale on paper, and copy them on the cutter as truly as pos- 
sible by the eye. 

Supposing the cutter has been properly shaped, hardened 
and completed and the steel pinion heads all turned to the 
diameter of the brass gauge, the cutting may be proceeded 
with without fear of spoiling, or further loss of time which 
might be spent in cutting the long pinion leaves; and even 
what is of more importance in work which does not allow of 



THE MODEllN CLOCK. 229 

any imperfection, removing the temptation, which might be 
strong, to let a pinion go, knowing it to be less perfect than 
it should be. 

Assuming the pinion teeth to be satisfactorily cut, the next 
operation will be hardening and tempering. A good way of 
doing this is to enclose one at a time in a piece of gas pipe, 
filling up the space around the pinion with something to 
keep the air off the work and prevent any of the products of 
combustion attacking the steel and so injuring the surface. 
Common soap alone answers the purpose very well, or it 
may have powdered charcoal mixed with it; also the addi- 
tion of common salt helps to keep the steel clean and white. 
The heating should be slow, giving time for the pinion and 
the outside of the tube to both acquire the same heat. Over- 
heating should be carefully avoided, or there w^ill be scaling 
of the surfaces, injurious to the steel, and requiring time and 
labor to polish off. There is no better way of hardening 
than by dipping the pipe with the pinion enclosed in plain 
cold water, or if the pinion should drop out of the tube into 
the water it will do all the same. To be sure the hardening 
is satisfactory it will be as well not to trust to the clean white 
color likely to result from this treatment, but try both ends 
and the center with a file. After all this has been success- 
fully accomplished the pinions will require tempering, the 
long arbors straightening, and the teeth polishmg. 

The drilled pinion heads, if hardened at all by the method 
last mentioned, will, on account of their short lengths, be 
equally hardened all over, but if the pinion and arbor should 
be all in one piece care will be needed to ensure equal heat- 
ing all over, or one part may be burnt and another soft. 
Also, to guard against bending the long arbors, the packing 
in the tube will need to be carefully done, so as to produce 
equal pressure all over ; otherwise, while the steel is red hot, 
and consequently soft enough to bend, even by its own 
weight, it may get distorted before dropping in the water. A 
long thin rod like this almost invariably bends if heated on 



230 THE MODERN CLOCK. 

an open fire unless equally supported all along; if hardened 
so, a little tin tray may be bent up, filled with powdered 
charcoal, and the pinion bedded evenly in it. Either this way 
or with a tube the long arbor may get bent before being 
quenched; but if the arbor, though kept straight up to this 
point, should happen to be dropped sideways into the water 
the side cooled first would contract most. To avoid this, 
the arbor should be dropped endways, as vertically as pos- 
sible. • 

Tempering the Pinions. — For common cheap work the 
usual and quickest way is what is called "blazing off." That 
is done either by dipping each piece singly in thick oil and 
setting the oil on fire, allowing it to burn away, or placing 
a number of pieces in a suitably sized pan, covering with 
oil, and burning it. The result is the same either way, the 
method being simply a matter of convenience regulated 
by the number of pieces to be tempered at one time. As 
the result of blazing off is to some extent uncertain, and 
the pinions apt to be too soft, it will be advisable to ndopt 
the process of bluing, by which the temper desired may be 
produced with more accuracy. The first thing to do will 
be to clean the suriace of the arbor all along on one side ; 
the pinion head may be left alone. As the pinion head 
would get overheated before the arbor had reached the blue 
color, if the piece were simply placed on a bluing pan or 
a lump of hot iron, it will be necessary to provide a layer 
of som€ soft substance to bed the pinion on ; iron, steel or 
brass filings answer well because the heat is soon uniformly 
distributed through the mass, and by judiciously moving the 
lamp an equable temper may be got all along, as deter- 
mined by the color. There is another and very sure way 
of getting a uniform temper, in using which there is no 
need to polish the arbors. The heat of lead at the point of 
fusion happens to be just about the same as that required 
for the tempering of this work; so if a ladle full of lead 



THE MODERN CLOCKc 231 

is available each pinion may be buried in it for a few sec- 
onds, holding it down beneath the molten surface with hot 
pHers. The temper suitable is indicated by a pale blue, a 
little softer than for springs, and a piece of poHshed steel 
set floating on the lead will indicate whether the heat is 
suitable; if found too great some tin may be added, which 
will cause the metal to melt at a lower temperature. Over- 
heating the metal must be avoided: it should go no higher 
than the bare melting point. 

Straightening Bent Arbors. — When. all care has been 
taken in the hardening, the long pieces of wire are still 
apt to become bent more or less, and this is especially the 
case with solid pinions ; so before proceeding further the 
pieces must be got true, or as nearly so as possible, and it 
will be found impracticable to do this by simple bending 
when the steel is tempered. If the piece is placed between 
centers in the lathe and rotated slowly, the hollow side will 
be found; this side must be kept uppermost while the steel 
is held on a smooth anvil, and the pene, or chisel-shaped, 
end of a small hammer applied crossways with gentle 
blows, stepping evenly along so that each portion of the 
steel is struck all along the part which is hollow ; this will 
stretch the hollow side, and, by careful working, trying the 
truth from time to time, the piece can be got as true as may 
be wished, and probably keep so during the subsequent turn- 
ing and finishing, though it is advisable to keep watch on it, 
and if it shows any tendency to spring out of truth again, 
repeat the striking process, which should always be done 
gently and in such a way as to show no hammer marks. 
Having got the pieces suf^ciently true in this way, each 
arbor may have a collet of suitable size driven on to it for 
permanency, and as the collets will probably be a little out 
of truth they may have a finishing cut taken all over them 
and receive a final polish. 



232 THE MODERN CLOCK. 

Polishing. — To polish the steel arbors after turning, a 
flat metal polisher, iron or steel, is used; this with emery 
or oilstone dust and oil produces a true surface, with a 
sharp corner at the shoulder; the polisher will require fre- 
quent filing on the flat and the edge to keep it in shape 
with a sharp corner, and a grain crossing like the cuts on 
a file to hold the grinding material. The polishing of ar- 
bors is not done with the object of making them shine, but 
to get them smooth and true, so there is no need of using 
any finer stuff than emery or oilstone dust. 

An old way to polish the leaves was to use a simple 
metal polisher of a suitable thickness, placing the pinion on 
a cork or piece of wood, or even holding it in the fingers ; 
working away at a tooth at a time until a good enough pol- 
ish was obtained; but this method, while being satisfactory 
as to results, was also tedious and very slow. 4t was in 
some cases assisted by having guide pinions fitted tight on 
one or both ends of the arbors to prevent rounding of the 
teeth, the polisher resting in the guide and the tooth to be 
polished. On the American lathes an accessory is provided 
called a "wig wag." This is a rod fastened at one end to a 
pulley by a crank pin near its circumference ; the pulley 
being rotated by a belt from the counter shaft pulleys 
causes the rod to move rapidly backwards and forwards. 
On the other end of the rod a long narrow piece of lead 
or tin is fixed, the pinion being fitted by its centres into a 
simple frame held in the slide rest so that it can be rotated 
tooth by tooth; the lead soon gets cut to the form of the 
teeth, and the polishing is quickly effected. Another way 
is to take soft pine or basswood, shape it roughly to about 
the form of space between two teeth and use it as a file, 
with emery and oil or oilstone dust. The wood is soon cut 
to the exact shape of the teeth, and then makes a quick and 
perfect job. The pinion is held in the jaws of the vise and 
the wooden polisher used as a file with both hands. 



THE MODERN CLOCK. 



233 



Where there is much polishing to do a simple tool, 
which a workman can form for himself, produces a result 
which is all that can be desired. It consists of an arbor 
to work between the lathe centres, or a screw chuck for 
wood, with a round block of soft wood, of a good diameter, 
fixed on it, and turned true and square across ; this will get 
a spiral groove cut in it by the corners of the pinion leaves. 
The pinion is set between centres in a holder in the slide 
rest, with the holder set at a slight angle, so that, instead of 
circular grooves being cut in the wood a screw will be 
formed, the angle being found by trial. On the wood block 
being rotated and supplied with fine emery the pinion will 
be found to rotate, and, being drawn backwards and for- 
wards by the slide rest, can be polished straight, while the 
circular action of the polisher will cause the sides of the 
pinion leaves to be made quite smooth and entirely free 
from ridges. 

If it should be desired to face the pinions, like watch 
pinions, it may be done in the same way, by cutting hollows 
so as to leave only a fine ring round the bottoms of the 
teeth, and using a hollow polisher with a flat end held in the 
fingers while the pinion is rotating. A common cartridge 
shell with a hole larger than the arbor drilled in the center 
of the head makes a fine polisher for square facing on the 
ends of pinions, while a stick of soft wood will readily adapt 
itself to moulded ends. 

The pinion heads being finished and got quite true, the 
arbors may be turned true and polished. It is not advisable 
to turn the arbors small ; they will be better left thick so as 
to be stiff and solid, as the weight so near the center is of 
no importance, the velocity on the small circumference in 
starting and stopping being also inappreciable. The thick- 
ness of the arbors when the pinion heads are drilled is de- 
termined by the necessity of having sufficient body inside 
the bottoms of the teeth ; but when solid they may with ad- 
vantage be left thicker; however, there is no absolute size. 



234 



THE MODERN CLOCK. 



The ends on which the collets for holding the wheels are to 
be fixed may be turned to the same taper as the broach 
which will be used for opening the collet holes, while the 
other ends may be straight. 

'None of the wheels in a fine clock should be riveted 
to the pinion heads ; even the center wheel, which goes quite 
up to the pinion head, is generally fixed on a collet. The 
collets are made from brass cut off a round rod, the outside 
diameters being just inside the edges of the wheel hubs, 
and a shoulder turned to fit accurately into the center hole 
of each wheel. These collets should first have their holes 
broached to fit their arbors, allowing a little for driving on, 
as they may be made tight enough in this way without sol- 
dering. Be careful to keep the broach oiled to prevent 
sticking if you want a smooth round hole. 

The holes in the wheels being made, each collet may be 
turned to a little over its final size all over, and then driven 
on to its place on the pinion, so that a final turning may be 
made to ensure exact truth from the arbors' own centers. 
When the collets are thus finished in their places .on the ar- 
bors, and the wheels fitted to them, if it is a fine clock, such 
as a regulator, a hole may be drilled through each wheel 
and its collet to take a screw, the holes in the collet tapped, 
the holes in the wheels enlarged to allow the screw to pass 
freely through, and a countersink made to each, so that the 
screws, when finished, may be flush with the wheels. One 
hole having been thus made and the wheel fixed with a 
screw, the other two holes can be made so as to be true, 
which would not be so well accomplished if all the holes 
were attempted at once. The spacing of the three screws 
will be accurate enough if the wheel arms be taken as a 
guide. If all this has been correctly done, the wheels will 
go to their places quite true, both in the round and the flat, 
and may be taken off for polishing, and replaced true with 
certainty, any number of times. 



THE MODERN CLOCK. 235 

The polishing of the pivots should be as fine as possible ; 
all should be well burnished, to harden them and make them 
as smooth as possible if it is a common job; if a fine one 
with hardened arbors the pivots may be ground and pol- 
ished as in watch work ; if the workman has a pivot polisher 
and some thin square edged laps this is a short job and 
should be done before cutting off the centers and rounding 
the ends of the pivots. During all this work the wheels, 
as a matter of course, will be removed from the pinions, and 
m.ay now be again temporarily screwed on, the polishing of 
them being deferred till the last, as otherwise they would 
be liable to be scratched. 

Lantern Pinions. — The lantern pinion is little under- 
stood outside of clock factories and hence it is generally 
underrated, especially by watchmakers and those working 
generally in the finer branches of mechanics. It will never 
be displaced in clock work, however, on account of the fol- 
lowing specific advantages : 

I. It offers the greatest possible freedom from stoppage 
owing to dirt getting into the pinions, as if a piece large 
enough to jam and stop a clock with cut pinions, gets into 
the lantern pinion, it will either fall through at once or be 
pushed thiough between the rounds of the pinion by the 
tooth of the wheel and hence will not interfere with its 
operation. It is therefore excellently adapted to run under 
adverse circumstances, such as the majority of common 
clocks are subjected to. 

2. Without giving the reasons it is demonstrable that as 
smooth a motion may be got by a lantern pinion as by a 
solid radial pinion of twice the number, and that the force 
required to overcome the friction of the lantern is therefore 
much less than with the other. It follows that such pinions 
can be used with advantage in the construction of all cheap 
and roughly constructed clocks which are daily turned out 
in thousands to sell at a low price. 



236 THE MODERN CLOCK. 

3. We have before pointed out the enormous advantages 
of small savings per movement in clock factories which are 
turning out an annual product of millions of clocks, and 
without going into details, it is sufficient to refer to the 
fact that where eight or ten millions of clocks are to be 
made annually the difference in the cost of keeping up the 
drills and other tools for lantern pinions over the cost of 
similar work on the cutters for solid pinions is sufficient 
to have a marked influence upon the cost of the goods. 
Then the rapidity with which they can be made and the 
consequent smallness of the plant as compared with that 
which must be provided for turning out an equal number of 
cut pinions is also a factor. There are other features, but 
the above will be sufficient to show that it is unlikely that 
the lantern pinion will ever be displaced in the majority of 
common clocks. From seventy-five to ninety per cent of 
the clocks now made have lantern pinions. 

The main difference between lantern and cut pinions 
mechanically is that as there is no radial flank for the curve 
of the wheel tooth to press against in the lantern pinion 
the driving is all done on or after the line of centers, except 
in the smaller numbers, and hence the engaging or butting 
friction is entirely eliminated when the pinion is driven, 
as is always the case in clock work. Where the pinion is 
the driver, however, this condition is reversed and the driv- 
ing is all before the line of centers, so that it makes a very 
bad driver and this is the reason why it is never used as a 
driving pinion. This, of course, bars it from use in a large 
class of machinery. 

The actual making of lantern pinions will be found to 
offer no difficulties to those who possess a lathe with divid- 
ing arrangements, a slide rest, and a drill holder or pivot 
polisher to be fixed on it. The pitch circle, being through 
the centers of the pins, can be got with great accuracy by 
setting the drill point first to the center of the lathe, read- 
ing the division on the graduated head of the slide rest 



THE MODERN CLOCK. 237 

screw, and moving the drill point outwards to the exact 
amount of the semi-diameter of the pitch circle. This pre- 
supposes the slide rest screw being cut to a definite standard, 
as the inch or the meter, and all measurements of wheels' 
and pinions being worked out to the same standard, the 
choice of the standard being immaterial. If the slide rest 
screw is not standardized the pitch circle may be traced 
with a graver and the drill set to center on the line so 
traced. 

The heads of the pinions may be made either of two 
separate discs, each drilled separately, and carefully fitted 
on the arbor so that the pins may be exactly parallel with 
the arbor; or, of one solid piece bored through the center, 
turned down deep enough in the middle, and the drill sent 
right through the pin holes for both sides at one operation. 
The former way will be necessary when the number of pins 
is small, but the latter is better when the numbers are large 
enough to allow of considerable body in the center. In 
either case it is advisable to drill only part way through one 
shroud and to close the holes in the other with a thin brass 
washer pressed on the arbor and turned up to look like part 
of the shroud after the pins are fitted in the holes. This 
makes a much neater way of closing the holes than riveting 
and takes but a moment where only one or two pinions are 
being made. 

There is no essential proportion for the thickness of the 
pins or rounds. In mathematical investigations these are 
always taken at first as mere points of no thickness at all; 
then the diameters are increased to w^orkable proportions, 
and the width of the wheel-tooth correspondingly reduced 
until there is a freedom or a little shake. If much power 
has to be transmitted, the pins, or ''staves," as they are 
called in large work, have to be strong enough to stand the 
strain, but, as the strain in clockwork is very small, the pins 
need not be nearly as thick as the breadth of a wheel-tooth. 
In modern factory practice the custom is to have the diam- 



238 THE MODERN CLOCK. 

eter of the rounds equal to the thickness of the leaf of a cut 
pinion of similar size, the measurement being taken at the 
pitch circle of the cut pinion. As we have already given 
the proportions observed in good practice on cut pinions 
they need not be repeated here. Another practice is to have 
wheel teeth and spaces equal ; when this is done the spacing 
of all pinions above six leaf is to have the rounds occupy 
three parts and the space five parts. 

In some old church clocks, lantern pinions were much 
used, in many cases with the pins pivoted and working 
freely in the ends, or, as they called them, "shrouds," but 
this was a mistake, and they are never made so now. A 
simple way for clock repair work is to get some of the 
tempered steel drill rod of exactly the thickness desired, 
hold one end by a split chuck in the lathe, let the other end 
run free, and polish with a bit of fine emery paper clipped 
round it with the fingers, when the wire will be ready for 
driving through the pinion heads, the holes being made 
small enough to provide for the rounds being firmly held. 
The drill may be made of the same wire. The shrouds 
may be made either of brass or steel ; the latter need not be 
hardened, and, when the rounds are all in place and cut ofif, 
the ends may be polished as desired. In the case of a cen- 
ter wheel, where the pinion is close up to the wheel, and 
space cannot be spared, the collet on which the wheel is 
mounted may form one end of the pinion head. 

The Wheel Teeth. — The same principles of calculation 
belong to these and solid-cut pinions, the only difference 
being that the round pins require wheel teeth of a different 
shape from those suited to pinion leaves with radial sides. 
Both are derived from epicycloidal curves ; the curve used 
for lantern pinions is derived from a circle of the same size 
as the pitch circle of the pinion, while the curve for wheel 
teeth to drive radial-sided leaves is derived from a circle of 
half that diameter, so that the wheel teeth in the former 



THE MODERN CLOCK. 



239 




Fig. 73. Lantern pinion showing pitch circle. 




Fig. 74. Generating epicycloid curve for lantern pinion above ; com- 
pare with curve for cut pinion of same size pitch circle, page 206. 



240 THE MODERN CLOCK. 

are more pointed than in the latter. There also is a farther 
difference; as was explained in detail when treating of cut 
pinions, the curve of the wheel tooth presses upon the radial 
flank of the leaf inside its pitch circle. Now there is no 
radial flank in the lantern and the curve is generated from 
a circle of twice the diameter, so that it is twice as long — 
long enough to interfere — so it is cut off (rounded) just 
beyond the useful portion of the working curve of the wheel 
tooth. 

Pillars and arbors are simple parts, yet much costly ma- 
chinery is used in making them. The wire from which 
they are made is brought tothe factories in large coils, and 
is straightened and cut into lengths by machines. The 
principle on which wire is straightened in a machine is 
exactly the same as. a slightly curved piece of wire is made 
straight in the lathe by holding the side of a turning tool 
between the revolving wire and the lathe rest, which is an 
operation most of our readers must have practiced. The 
rapid revolution of the wire against the turning tool causes 
its highest side to yield, till finally it presses on the turning 
tool equally all round, and is consequently straight. How- 
ever, in straightening wire by machines the wire is not 
made to revolve, but remains stationary while the straight- 
ening apparatus revolves around it. Wire-straightening ma- 
chines are usually made in the form of a hollow cylinder, 
having arms projecting from the inside towards the center. 
The cylinder is open at both ends, and the arms are ad- 
justable to suit the different thicknesses of wire. The wire 
is passed through the ends of the cylinder, and comes in 
contact with the arms inside. A rapid rotary motion is 
then given to the cylinder, which straightens the wire in 
the most perfect manner, as it is drawn through, without 
leaving any marks on it when the machine is properly ad- 
justed. The long spiral lines that are sometimes seen on 
the w^ire w^ork of clocks is caused by this w^ant of adjust- 
ment; and they are produced in the same way as broad 



THE MODERN CLOCK. 



241 



circular marks would be made in soft iron wire if the side 
of the turning tool was held too hard against it when 
straightening it in the lathe. 

After the wire has been straightened it is cut off into 
the required lengths, and this operation is worthy of notice. 
If the thick sizes of wire that are used were to be cut by 
the aid of a file or a chisel, the ends would not be square, 
and some time and material would be lost in the operation 




Fig. 75. A Slide Gauge Lathe. 

of squaring them; and as economy of material as well as 
economy of labor is a feature in American clock manufac- 
ture, wire of all sizes is sheared or broken off into lengths, 
by being fed through round holes in the shears, which act 
the same as when a steady pin is broken when a cock or 
bridge gets a sudden blow on the side, or in the same man- 
ner as patent cutting plyers work. The wire is not bent in 
the operation, and both ends of it are smooth and flat. The 
wire for the pillars is then taken to a machine to have the 
points made and the shoulders formed for the frames to rest 
against. This machine is constructed like a machinist's 
bench lathe, with two headstocks. There is a live spindle 
running in both heads. In the ends of these spindles, that 
point towards the center of the lathe, cutters are fastened, 
and the one is shaped so that it will form the end and shoul- 



242 THE MODERN CLOCK. 

der of the pillar that is to be riveted, while the other is 
shaped so as to form the shoulder and point that is to be 
pinned. Between these two revolving cutters there is an 
arrangement, worked by a screw in the end of a handle, for 
holding the wire from which the pillar is to be made, in a 
firm and suitable position. The cutters are then made to 
act simultaneously on the ends of the wire by a lever acting 
on the spindles, and the points and shoulders are in this 
way formed in a very rapid manner, all of the same length 
and diameter. These machines are in some points auto- 
matic. The pieces of wire are arranged in quantities in a 
long narrow feed box that inclines towards the lathe, and 
the mechanism for holding the wire is so arranged that 
when its hold is loosened on the newly made pillar, the 
pillar drops out into a box beneath, and a fresh piece of 
wire drops in and occupies its place. 

In many of the factories, some clocks are manufactured 
having screws in place of pins to keep the frames together, 
and the pillars of these clocks are made in a different man- 
ner than that we have just described. The wire that is used 
is not cut into short lengths, but a turret lathe with a hol- 
low spindle is used, through which the wire passes, and is 
held by a chuck, when a little more than just the length 
that is necessary to make the pillar projects through the 
chuck. The revolving turret head of the lathe has cutting 
tools projecting from it at several points. One tool is 
adapted to bore the hole for the screw, and when it is bored 
the next tool taps the hole to receive the screw, while an- 
other forms the point and shoulder ; and after that end of 
the pillar is comipleted another tool attached to the slide 
of the lathe forms the other shoulder, prepares that end for 
riveting, and cuts it off at the same time. One thousand 
of these pillars are in this manner made in a day on each 
machine. The screws that screw into them are made on 
automatic screw machines. The latest improvements .in this 
direction being to first turn the blanks and then roll the 
threads on thread rolling machines. 



THE MODERN CLOCK. 243 

The pinion arbors, after they have been cut to length, are 
centered on one end by a milling machine having a conical 
cutter made for the purpose. The collets for the pinion 
heads, and the one to fasten the wheel by, are punched out 
of sheet brass, and a hole is drilled in their centers a little 
smaller than the wire ; and to drive them on, in most in- 




Fig. 76. Slide Gauge Tools and Rack. 

stances, is all that is necessary to hold them. At one time 
it was the practice to drive these collets by hand. One was 
placed on the point of the arbor, and the point was then 
placed over a piece of steel, with a series of holes in it 
of such depths that the collets would be in their proper 
position on the arbor when the point was driven to the 
bottom of the hole, but this method has now been super- 
seded by automatic machinery, which will be described 



244 '1'^^ MODERN CLOCK, 

later. It is impossible to give an intelligible description of 
these machines without drawings. All we can say at 
present is that they perform their work in a very rapid and 
effective manner, and are in use by all the larger clock fac- 
tories. 

The barrels of weight clocks are mostly made from 
brass castings, and slight projections are raised on the sur- 
face of their arbors by swedging, so as to prevent the 
arbors from getting loose in the barrels after repeated wind- 
ing of the clock. This swedging and all the other opera- 
tions in making arbors used to be done on separate ma- 
chines; but the largest companies now use a powerful and 
comprehensive machine that works automatically, and 
straightens any size of wire necessary to be used in a clock, 
cuts it to the length, centers it, and also swedges the pro- 
jections on the barrel arbors, or any of the other arbors 
that may be necessary. A roll of wire is placed on a reel 
at one end of the machine, first passing through a straight- 
ening apparatus, and afterwards to that portion of the ma- 
chine where the cutting, swedging and centering are exe- 
cuted, and the finished arbors drop into a box placed ready 
to receive them. The saving effected by the use of this 
machine is very great, and in some instances amounts to a 
thousand per cent over the method of straightening, cutting, 
swedging and centering on different machines, at different 
operations. 

Boring the holes in the arbors of the locking work, to 
receive the smaller wires, and the pin holes in the points 
of the pillars, is done by small twist drills, run by small 
vertical drill presses. The work is held in adjustable frames 
under the drill, and when more than one hole has to be 
bored this frame is moved backward or forward between 
horizontal slides to the desired distance, which is regulated 
by an adjustable stop, so that every hole in each piece is 
exactly in the same position. In arbors where holes have 
to be bored at right angles to each ether, the arbor is turned 



THE MODERN CLOCK. 



245 



round to the desired position by means of an index. The 
holes in the locking work arbors are bored just the size 
to fit the wire that is to go into them, and these small 







1 ' **i3l^. "" 




^i 


4 


ttiJIi- 






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f 


i 


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Fig. 77. Automatic Pinion Making Machine of the Davenport Machine 

Company. 



wires are easily and rapidly fastened in place by holding 
them in a clamp made for the purpose, and riveting them 
either with a hammer or with a hammer and punch. 



246 THE MODERN CLOCK. 

The Slide Gauge Lathe — The system of turnin;^^ with 
the sUde gauge lathe, formerly adopted for lantern pinions 
in the clock factories, would seem to the watchmaker of a 
peculiarly novel nature. The turning tools are not held in 
the hand, in the manner generally practiced, neither are 
they held in the ordinary sHde rest, but are used by a com- 
bination of both methods, which secures the steadiness of 
the one plan and the rapidity of the other. Adjustable 
knees are fastened to the head and tail stocks of the lathCj 
Figs. 75 and 76, which answer the purpose of a rest ; both 
the perpendicular and horizontal parts of these knees being 
fastened perfectly parallel with the centers of the lathe. 
A straight, round piece of iron, of equal thickness, and 
having a few inches in the center of a square shape, mor- 
tised for the reception of cutters, is laid on these knees, 
and answers the purpose of a handle to hold the cutting 
tools. Two handles will thus hold eight tools, one set for 
brass and one for steel. On every side of the square part 
of this iron bar, or what we will now call the turning tool 
handle, a number of cutting tools are fastened by set screws, 
and the method of using them is as follows : The operator 
holds the tool handle with both hands on to the knees that 
are fastened to the head and tail stocks of the lathe, with 
the turning tool that is desired to be used pointing towards 
the center, and it is allowed to come in contact with the 
work running in the lathe in the usual manner practiced in 
turning. Fig. 76 is from a photo furnished by Mr. H. E. 
Smith of the Smith Novelty Co., Hopewell, N. J., and 
shows the tools in the rack, w^hich is wound with leather 
so that the tools may be rapidly thrown in place without 
injury. 

If a plain, straight piece of work is to be turned, the 
tool is adjusted in the handle so that the work will be of 
the proper diameter when the round parts of the handle 
come in contact with the perpendicular part of the knees 
or rest; and while the handle is thus held and moved gently 



THE MODERN CI.OCK. 



247 



^]]I3 Stock advanced. 



V 



p 



First collet driven. 



Second collet driven. 



Third collet driven. 



n 



Ri 




Shoulder turned. 



First sides faced. 



Second sides faced. 




fO 



Pivots turned. 



^]=n=I 



Pivots burnished. 



Cut oft. 



Fig. 78. 



Showing Successive Steps in Turning on Automatic Pinion 
Making Machine. 



248 THE MODERN CLOCK. 

along in the corners of the knees, with the tool sliding on 
the T-rest, the work is easily turned perfectly parallel, 
smooth and true. Sometimes a roughing cut is taken by 
holding the bar loosely and then a finishing cut is made 
with the same tool by holding it firmly in place. In turning 
a pinion arbor, for instance, the wire having been previously 
straightened and cut to length and centered, and the brass 
collets to make the pinion and to fasten the wheel having 
l)een driven on, one end is held in the lathe by a spring 
chuck fastened to the spindle of the lathe, while the other 
end works in a center in the other head. One turning tool 
is shaped and adjusted in the handle for the purpose of 
turning the brass collets for the pinion to the proper diam- 
eter, another turns the sides of the brass work, while others 
are adapted for the arbors, pivots, and so on, pins being 
placed in holes in the T-rest to act as stops for the tools. 
After the brass work has been turned, the positions of the 
shoulders of the pivots are marked with a steel gauge, and 
by simply turning round the handle of the turning tool till 
the proper shaped point presents itself, each operation is 
accomplished rapidly, and the cutting is so smooth that 
even for the pivots all that is necessary to finish them is 
simply to bring them in contact with a small burnisher. 
The article is not taken from the lathe during the whole 
process of turning, and when completed the centers are 
broken off, having been previously marked pretty deep at 
the proper place wi'th a cutting point. Five hundred to 
1,200 arbors per day, per man, is the usual output. All 
the pinions, arbors, and barrels — in fact every part of an 
American clock movement that requires turning — were for- 
merly done in this manner, at long rows of lathes in rooms, 
and by workmen set apart for the purpose. But perhaps it 
may be well to mention that in the machine shops of these 
factories, where they make the tools, the ordinary methods 
of turning with the common hand tool, and by the aid of 
ordinary and special slide rests, are practiced the same as it 



THE MODERN CLOCK. 



'49 




No. 79. Automatic Pinion Drill of the Davenport Machine Company. 



250 THE MODERN CLOCK. 

is among other machinists. In the large factories automatic 
turret machines are now coming into use and these are 
shown in Figs., 77, 78 and 79. 

The lantern pinions of an American clock have long been 
a mystery to those unacquainted with the method of their 
manufacture, and the usual accuracy in the position of the 
small wires or "rounds/' combined with great cheapness, 
has often been a subject of remark. The holes for the 
wires in these pinions are drilled in a machine constructed 
as follows: An iron bed with two heads on it, Fig. 80, one 
of which is so constructed that by pulling a lever the spin- 
dle has a motion lengthwise as well as the usual circular 
motion, and on the point of this spindle, which is driven at 
22,000 revolutions, the drill is fastened that is to bore tne 
holes in the pinions ; the other head has an arbor passing 
through it with an index plate attached, having holes in the 
plate, and an index finger attached to a strong spring going 
into the holes, the same as in a wheel-cutting engine; on 
this head, and on the end of it that faces the drill, there is 
a frame fastened in which the pinion that is to be bored 
is placed between centers, and is carried round with the 
arbor of the index plate,, in the same manner as a piece of 
work is carried round in an ordinary lathe by means of a 
dog, or carrier; only in the pinion drilling machine the 
carrier is so constructed that there is no shake in any way 
between the pinion and the index arbor. This head is car- 
ried on a slide having a motion at right angles to the spindle 
of the other head, by w^iich means the pitch diameter of 
the proposed pinion is adjusted. The head is moved in the 
slide by an accurately cut screw, to which a micrometer is 
attached that enables the workman to make an alteration 
in the diameter of a pinion as small as the one-thousandth 
part of an inch. The drill that bores the holes is the ordi- 
nary flat-pointed drill, and has a shoulder on its stem that 
stops the progress of the drill when it has gone through 
the first part of the pinion head and nearly through the 



THE MODERN CLOCK. 



251 



other. All operators make their own drills and the limits 
of error are for pitch diameter .0005 inch; error of size of 
drills .0001. The reader can see that these men must know 
something of drill making. 

The action of the machine is simple. The pinion, after 
it has been turned, pivoted and dogged, is placed in its 




Fig. 80. Pinion Drilling Machine. 



position in the machine, and by pulling a lever, the drill, 
which is running at a speed of about 22,000 revolutions a 
minute, comes in contact with the brass heads of the pinion 
and bores the one through and the other nearly through. 
The lever is then let go, and a spring pulls the drill back ; 
the index is turned round a hole, and another hole bored in 
the pinion, and so on till all the holes are bored. An ordi- 
nary expert workman, with a good machine, will bore 
about fourteen hundred of medium-sized pinions in a day. 



25^ 



THE MODERN CLOCK. 



The wires or ''rounds" are cut from drill rod and are put 
into the holes by hand by girls who become very expert at 
it. This is called "filling." We have already stated that 
the holes are only bored partly through one of the pieces 
of the brass, and after the wire has been put in, the holes 
are riveted over, and in this manner the wires are fastened 
so that they cannot come out. Some factories close the 
holes by a thin brass washer forced on the arbor, instead of 
riveting. 

Figs, "j^j, 78 and 79 show the automatic pinion turning 
machine and its processes in successive operations. These 
machines are used by most of the large clock manufacturers 
of the United States and some of the European concerns 
also. They are entirely automatic, will make 1,500 pinions 
per day, as an average, and one man can run four ma- 
chines. 

Fig. 79 shows an automatic pinion drilling machine, 
which takes up the work where it is left by the' machine 
shown in Fig. ']']. This machine will drill 4,000 to 5,000 
pinions per day according to the size hole and the number 
of holes. The operator places the pinions in the special 
chain shown in the front of the machine, from which the 
transport arms ca^*-y them to the spindle, where they are 
drilled and when completed drop out. One operator can 
feed three of these machines. 

Making Solid Pinions. — The solid steel pinions are not 
hardened, but are made of Bessemer steel, which could only 
be case hardened — a thing hardly ever done. The process 
of making these pinions is as follows : Rods of Bessemer 
steel are cut into suitable lengths. The pieces obtained are 
pointed or centered on both ends. The stock not needed for 
the pinion head is cut away, leaving the arbors slightly 
tapering, for the purpose of fastening them by this means 
in a hole on the cutting machine. On the end of the arbor 
of the index plate are two deep cuts across its center, and 



THE MODERN CLOCK. 253 

at right angles to each other. These cuts are of the same 
shape that would be made by a knife-edged file. The effect 
of these cuts is to produce a taper hole in the end of the 
arbor, with four sharp corners. Into this hole the end of 
the arbor of the pinion or ratchet that is to be cut is placed, 
and a spring center presses on the other end, and the sharp 
corners in the hole hold the work firm enough to prevent it 
from turning round when the teeth are being cut. The 
marks that are to be seen on the shoulder of the back pivot 
of the arbor that carries the minute hand of a Yankee clock 
is an illustration of this method of holding the pinion when 
the leaves are being cut, and no injurious effects arise from 
it. The convenience the plan affords for fastening work in 
the engine enables twenty-five hundred of these pinions to 
be cut in a day, one at a time. The pinion head is cut sub- 
ject to the proper dividing plate by a splitting circular saw, 
and by a milling tool (running in oil) for forming the shape 
of the leaves, both of which tools are generally carried on 
the same arbor, both being shifted into their proper places 
by an adjusting attachment. Pinion leaves of the better 
class are generally shaped by two succeeding milling cut- 
ters, the second one of which does the finishing, obviating 
any other smoothing. For very cheap work the arbors re- 
ceive no further finish. The shaping of the pivots, done by 
an automatic lathe, finishes the job. 

Figure 8i shows an automatic pinion cutting machine 
which has extensive use in clock factories for cutting pinions 
up to one-half inch diameter and also the smaller wheels. 
For wheels the work is handled in stacks suited to the tra- 
verse of the machine, the work being treated as if the stacks 
were long brass pinions. 

Wheels are cut in two ways, on automatic wheel cutters 
as just described and on engines containing parallel spindles 
for the cutters, carried in a yoke which rises and falls, so 
that it clears the work while the carriage is returning to 
the starting point on each trip and engages it on the out- 



254 



THE MODERN CLOCK. 



ward trip. The cutters are about three inches in diameter 
and rapidly driven; the first is a saw, the second a roughing 
cutter, and the third a finishing cutter. The carriage is 




Fig. 81. Automatic Wheel and Pinion Cutters. 



driven by a rack and pinion operated by a crank in the 
hands of the workman and streams of soda water are used 
on the cutters and work to carry away the heat, as brass 
expands rapidly under heat, and if the stack were cut dry 



THE MODERN CLOCK. 



255 



the cut would get deeper as the cutting proceeded, owing 
to the expansion of the brass, and hence the finished wheel 
would not be round when cold, if many teeth were being 
cut. The stacks of wheels are about four inches in 
length and the slide thus travels about twenty inches in 




Fig. 82. Wheel Cutting Engine. 



order to clear the three arbors and engage with the shifter 
for the index. The last wheel of the stack has a very large 
burr formed by the cutters as they leave the brass and this 
wheel is removed from the stack when the arbor is taken 
out and placed aside to have the burrs removed by rubbing 
on emery paper. 



256 THE MODERN CLOCK. 

■This is one of the few instances in which automatic ma- 
chinery has been unable to displace hand labor, as the work 
is done so quickly that the time of the attendant would be 
nearly all taken up in placing and removing the stacks, 
and so the feeding is done by him as well. About 35,000 
wheels per day can be thus cut by one man, with girls to 
stack the blanks on the arbors, and an automatic feed would 
not release the man from attendance on the machine, so 
that the majority of clock wheels are cut to-day as they 
were forty years ago. Still, some of the factories are add- 
ing an automatic feed to the carriage in the belief that the 
increased evenness of feed will give a more accurately cut 
wheel, a proposition which the men most vigorously deny. 
Such a machine, they say, to be truly automatic, miust take 
its stacks of wheels from a magazine and discharge the 
work when done, so that one attendant could look after a 
number of machines. This would result in economy, as well 
as accuracy, but has not been done owing to the great vari- 
ations in sizes of wheels and numbers of teeth required in 
clock work. 

Figure 82 shows one of these machines, a photograph of 
which was taken especially for us by the courtesy of the 
Seth Thomas Clock Company at their factory in Thomas- 
ton, Conn. 

About every ten years some factory decides to try stamp- 
ing out the teeth of wheels at the same time they are being 
blanked ; this can, of course, be done by simply using a 
more expensive punch and die, and at first it looks very at- 
tractive ; but it is soon found that the cost of keeping up 
such expensive dies makes the wheels cost more than if 
regularly cut and for reasons of economy the return is 
made to the older and better looking cut wheels. 

After an acid dip to remove the scale on the sheet brass, 
followed by a dip in lacquer, to prevent further tarnish, 
the wheels are riveted on the pinions in a specially con- 
structed jig which keeps them central during the rivetting 



THE MODERN CLOCK. 257 

and when finished the truth of every wheel and its pinions 
and pivots are all tested before they are put into the clocks. 
The total waste on all processes in making wheels and pin- 
ions is from two to five per cent, so that it will readily be 
seen that accuracy is demanded by the inspectors. Euro- 
pean writers have often found fault with nearly everything 
else about the Yankee clock, but they all unite in agreeing 
that the cutting and centering of wheels, pinions and pivots 
(and the depthing) are perfect, while the clocks of Ger- 
many, France, Switzerland and England (particularly 
France) leave much to be desired in this respect; and much 
of the reputation of the Yankee clock in Europe corties from 
the fact that it will run under conditions which would stop 
those of European make. 

We give herewith a table of clock trains as usually manu- 
factured, from which lost wheels and pinions may be easily 
identified by counting the teeth of wheels and pinions which 
remain in the movement and referring to th-e table. It will 
also assist in getting the lengths of missing pendulums by 
counting the trains and referring to the corresponding 
length of pendulums. Thus, with 84 teeth in the center 
wheel, 70 in the third, 30 in the escape and 7-leaf pinions, 
the clock is 120 beat and requires a pendulum 9.78 inches 
from the bottom of suspension to the center of the bob. 

To Calculate Clock Trains. — Britten gives the fol- 
lowing rule: Divide the number of pendulum vibrations 
per hour by twice the number of escape wheel teeth; the 
quotient will be the number of turns of escape wheel per 
hour. Multiply this quotient by the number of escape 
pinion teeth, and divide the product by the number of third 
wheel. This quotient will be the number of times the teeth 
of third wheel pinion must be contained in center wheel. 

Take a pendulum vibrating 5,400 times an hour, escape 
wheel of 30, pinions of 8, and third wheel of ']2. Theri 
5,40CK-6o=90. And 90X8-^-72=10. That is, the center 



258 



THE MODERN CLOCK. 



Clock Trains and Lengths of Pendulums* 



" 1 


o 




to , r! 

If 


5?'2 c 


V) 


,o 


c4 <1> 


m 


III 


§ 










1 


"c 








120 90 75 


10 10 9 


Double 


*30 


156.56 


96 76 


8 


30 


114 


10.82 






31eg- 






115 100 


10 


30 


115 


10-65 






ffo' 






84 78 


7 


26 


115.9 


10.49 


120 90 90 


10 9 9 


*40 


88.07 


96 80 


8 


30 


120 


9.78 


128 120 


16 


30 


60 


39.14 


84 70 


7 


30 


120 


9.78 


112 105 


14 


30 


60 


39.14 


84 78 


7 


27 


120.3 


9.73 


96 90 


12 


30 


60 


39.14 


90 84 


8 


31 


122 


9.46 


80 75 


10 


30 


60 


39.14 


84 78 


7 


28 


124.8 


9.02 


64 60 


8 


30 


60 


39.14 


100 80 


8 


30 


125 


9.01 


68 64 


8 


30 


68 


30.49 


90 84 


8 


32 


126 


8.87 


70 64 


8 


30 


70 


28.75 


100 96 


10 


40 


128 


8.59 


72 64 


8 


30 


72 


27.17 


84 78 


7 


29 


129.3 


8.42 


75 60 


8 


32 


75 


25.05 


100 78 


8 


32 


130 


8.34 


72 65 


8 


32 


78 


23.15 


84 77 


7 


30 


132 


8.08 


75 64 


8 


32 


80 


22.01 


84 78 


7 


30 


133.7 


7.9 


84 64 


8 


30 


84 


19.97 


90 90 


8 


32 


135 


7.73 


86 64 


8 


30 


86 


19.06 


84 78 


7 


31 


138.2 


7.38 


88 64 


8 


30 


88 


18.19 


84 80 


8 


40 


140 


7.18 


84 78 


7 


20 


89.1 


17.72 


120 71 


8 


32 


142 


6.99 


80 72 


8 


30 


90 


17.39 


84 78 


7 


32 


142.6 


6.93 


84 78 


7 


21 


93.6 


16.08 


100 87 


8 


32 


145 


6.69 


94 64 


8 


30 


94 


15.94 


84 78 


7 


33 


147.1 


6.5 


84 78 


8 


■ 28 


95.5 


15.45 


100 96 


8 


30 


150 


6.26 


108 100 


12&10 


32 


96 


15.28 


84 78 


7 


34 


151.6 


6.1 


84 84 


9& 8 


30 


98 


14.66 


96 95 


8 


32 


152 


6.09 


84 78 


7 


22 


98 


14.66 


84 77 


7 


35 


154 


5.94 


84 78 


8 


29 


98.9 


14.41 


104 96 


8 


30 


156 


5.78 


80 80 


8 


30 


100 


14.09 


84 78 


7 


35 


156 


5.78 


85 72 


8 


32 


102 


13.54 


120 96 


9&8 


30 


160 


5.5 


84 78 


8 


30 


102.4 


13.44 


84 78 


7 


36 


160.5 


5.47 


84 78 


7 


23 


102.5 


13.4 


84 78 


7 


37 


164.9 


5.15 


105 100 


10 


30 


105 


12.78 


132 100 


9&8 


27 


165 


5.17 


84 78 


8 


31 


105.8 


12.59 


84 78 


7 


38 


169.4 


4.88 


84 78 


7 


24 


107 


12.3 


128 102 


8 


25 


170 


4.87 


96 72 


8 


30 


108 


12.08 


84 78 


7 


39 


173.8 


4.65 


84 78 


8 


32 


109.2 


11.82 


36 36 35 


6 


25 


175 


4.6 


88 80 


8 


30 


110 


11.64 


84 77 


7 


40 


176 


4.55 


84 77 


7 


25 


110 


11.64 


84 78 


7 


40 


178.3 


4.43 


84 78 


7 


25 


111.4 


11.35 


45 36 36 


6 


20 


180 


4.35 


84 80 


8 


32 


112 


11.22 


47 36 36 


6 


20 


188 


3.99 


84 78 


8 


33 


112.6 


11.11 













*These are good examples of turret clock trains; the great wheel (120 teeth) 
malces in both instances a rotation in three hours, From this wheel the hands 
are to be driven. This may be done by means of a pinion of 40 gearing with the 
great wheel, or a pair of bevel wheels bearing the same proportion to each 
other (three to one) may be used, the larger one being fixed to the great wheel 
arbor. The arrangement would in each case depend upon the number and posi- 
tion of the dials. The double three-legged gravity escape wheel moves through 
60° at each beat, and therefore to apply the rule given for calculating clock 
•trains it must be treated as an escape wheel of three teeth. 



THE MODERN CLOCK. 



259 



wheel must have ten times as many teeth as the third wheel 
pinion, or ten times 8=80. 

The center pinion and great wheel need not be consid- 
ered in connection with the rest of the train, but only in 
relation to the fall of the weight, or turns of mainspring, 
as the case may be. Divide the fall of the weight (or twice 
the fall, if double cord and pulley are used) by the circum- 
ference of the barrel (taken at the center of the cord) ; 
the quotient will be the number of turns the barrel must 
make. Take this number as a divisor, and the number of 
turns made by the center wheel during the period from 
winding to winding as the dividend; the quotient will be 
the number of times the center pinion must be contained in 
the great wheel. Or if the numbers of the great wheel and 
center pinion and the fall of the weight are fixed, to find 
the circumference of the barrel, divide the number of turns 
of the center wheel by the proportion between the center 
pinion and the great wheel ; take the quotient obtained as a 
divisor, and the fall of the weight as a dividend (or twice 
the fall if the pulley is used), and the quotient will be the 
circumference of the barrel. To take an ordinary regulator 
or 8-day clock as an example — 192 (number of turns of 
center pinion in 8 days)-i-i2 (proportion between center 
pinion and barrel wheel) := 16 (number of turns of barrel). 
Then if the fall of the cord^ 40 inches, 40X2-^16=5, 
which would be circumference of barrel at the center of the 
cord. 

If the numbers of the wheels are given, the vibrations per 
hour of the pendulum may be obtained by dividing the prod- 
uct of the wheel teeth multiplied together by the product of 
the pinions multiplied together, and dividing the quotient by 
twice the number of escape wheel teeth. 

The numbers generally used by clock makers for clocks 
with less than half-second pendulum are center wheel 84, 
gearing with a pinion of 7 ; third wheel 78, gearing with a 
pinion of 7. 



26o' THE MODERN CLOCK. 

■ The' product obtained by multiplying too^ether the center 
pnd third wheels=84X78=6,552. The two pinions multi- 
plied tcgether=7X7=49- Then 6,552^-49=133.7. So 
that for every turn of the center wheel the escape pinion 
turns 133.7 times. Or 133.7-^60=2.229, which is the num- 
ber of turns in a minute of the escape pinion. 

The length of the pendulum, and therefore the number 
of escape wheel teeth, in clocks of this class is generally de- 
cided with reference to the room to be had in the clock 
case, with this restriction, the escape wheel should not have 
less than 20 nor more than 40 teeth, or the performance will 
not be satisfactory. The length of the pendulum for all 
escape wheels within this limit is given in the preceding 
table. The length there stated is of course the theoretical 
length, and the ready rule adopted by clockmakers is 
to measure from the center arbor to the bottom of the 
inside of the case, in order to ascertain the greatest length 
of pendulum which can be used. For instance, if 
from the center arbor to the bottom of the case is 10 inches, 
they would decide to use a lo-inch pendulum, and cut the 
escape wheel accordingly with the number of teeth required 
as shown in the table. But they would make the pendulum 
rod of such a length as just to clear the bottom of the case 
when the pendulum was fixed in the clock. 

In the clocks just referred to the barrel or first wheel 
has 96 teeth, and gears with a pinion of eight. 

Month clocks have an intermediate wheel and pinion be- 
tween the great and center wheels. This extra wheel and 
pinion must have a proportion to each other of 4 to i to 
enable the 8-day clock to go 2i'^ days from winding to wind- 
ing. The weight will have to be four times as h^avy, plus 
the extra friction, or if the same weight is used there must 
be a proportionately longer fall. 

Six-months clock have two extra wheels and pinions be- 
tween the great and center wheels, one pair having a pro- 
portion of 4^ to I and the other of 6 to i. But there is an 



THE MODEliX CLOCK.J rlJl^j^ Af 4 o ^ 

enormous amount of extra friction generated in these clocks, 
and they are not to be recommended. 

The pivot holes and all the other holes in the frames, are 
punched at one operation after the frames have been 
blanked and flattened. They are placed in the press, and 
a large die having punches in it of the proper size and 
in the right position for the holes, comes down on the frame 
and makes the holes with great rapidity and accuracy. 
These holes are finished afterwards by a broach. In some 
kinds of clocks, where some of the pivot holes are very 
small, the small holes are simply marked with a sharp point 
in the die, and afterwards drilled by small vertical drills. 
These machines are very convenient for boring a number 
of holes rapidly. The drill is rotated with great speed, and 
a jig or plate on which the work rests is moved upwards 
towards the drill by a movement of the operator's foot. All 
the boring, countersinking, etc., in American clocks, is done 
through the agency of these drills. Bending the small 
wires for the locking work, the pendulum ball, etc., is rap- 
idly effected by forming. As no objectionable marks have 
been made on the surface of either the thick or smaller 
wires during any process of construction, all that is neces- 
sary to finish the iron work is simply to clean it well, which 
is done in a very effective manner by placing a quantity of 
work in a revolving tumbling box, which is simply a barrel 
containing a quantity of saw-dust. 

Milling the winding squares on barrel arbors is an in- 
genious operation. The machine for milling squares and 
similar work is made on the principle of a wheel-cutting en- 
gine. The work is held in a frame, attached to which is a 
small index plate, like that of a cutting engine. In the ma- 
chine two large mills or cutters, with teeth in them like a 
file, are running, and the part to be squared is moved in 
between the revolving cutters, which operation immediately 
forms two sides of the square. The work is then drawn 
back, and the index turned round, and in a like manner the 



262 THE MODERN CLOCK. 

other two sides of the square are formed. The cutting- 
sides of the mills are a little bevelled, so that they will pro- 
duce a slight taper on the squares. 

Winding keys have shown great improvements. Some 
manufacturers originally used cast iron ones, but the squares 
were never good in them, and brass ones were adopted. At 
first the squares were made by first drilling a hole and driv- 
ing a square punch in with a hammer; and to make the 
squares in eighteen hundred keys by this method was con- 
sidered a good day's work. Restless Yankee ingenuity, 
however, has contrived a device by which twenty or twen- 
ty-five thousand squares can be made in a day, while at the 
same time they are better and straighter squares than those 
by the old method; but we are not at hberty to describe 
the process at present, but only to state that it is done 
by what machinists call drilHng a square hole. 

Pendulum rods are made from soft iron wire, and the 
springs on the ends rolled out by rollers. Two operations 
are necessary. The first roughs the spring out on rollers 
of eccentric shape, and the spring is afterwards finished on 
plain smooth rollers. The pendulum balls in the best clocks 
are made of lead, on account of its weight, and cast in an 
iron mold in the same manner as lead bullets, at the rate 
of about eighteen hundred a day. A movable mandrel is 
placed in the mold to produce the hole that is in the center 
of the ball. The balls are afterwards covered with a shell 
of brass, polished with a blood-stone burnisher. The vari- 
ous cocks used in these clocks are all struck up from sheet 
brass, and the pins in the wheels in the striking part are all 
swedged into their shape from plain wire. The hands are 
die struck out of sheet steel, and afterwards polished on 
emery belts, and blued in a furnace. 

All the little pieces of these clocks are riveted together by 
hand, and the different parts of the movement, when com- 
plete, are put together by workmen continually employed 
in that department. Although the greatest vigilance is used 



THE MODERN CLOCK. 26^ 

in constructing the different parts to see that they are per- 
fect, when they come to be put together they are subjected 
to another examination, and after the movements are put 
in the, case the clocks are put to the test by actual trial be- 
fore they are packed ready for the market. As a general 
rule, all the different operations are done by workmen em- 
ployed only at one particular branch; and in the largest 
factories from thirty to fifty thousand clocks of all classes 
may be seen in the various stages of construction. 

Such is a description of the main points in which the man- 
ufacture of American clock movements differs from those 
manufactured by other systems. All admit that these clocks 
perform the duties for which they are designed in an ad- 
mirable manner, while they require but little care to m.an- 
age, and when out of order but little skill is necessar^^ to 
repair them. Of late years there has been a growing de- 
mand for ornamental mantel-piece clocks in metallic cases 
of superior quality, and large numbers of these cases of 
both bronze and gold finish are being manufactured, which, 
for beauty of design and fine execution, in many instances 
rival those of French production. The shapes of the ordi- 
nary American movements were, however, unsuitable for 
some patterns of the highest class of cases, and the full plate, 
round movements of the same size as the French, but with 
improvements in them that in some respects render them 
more simple than the French, are now manufactured. Ex- 
actly the same system is employed in the manufacture of 
the different parts of these clocks that is practiced in mak- 
ing the ordinary American movements. 



CHAPTER XV. 

SPRINGS, WEIGHTS AND POWER. 

We see by the preceding calculations that there is one 
definite point in the time train of a clock ; the center arbor, 
which carries the minute hand, must revolve once in one 
hour; from this point we may vary the train both ways, 
toward the escape wheel to suit the length of pendulum 
which we desire to use, and toward the barrel to suit the 
length of time we want the clock to run. The center arbor 
is therefore generally used as the point at which to begin 
calculations, and it is also for this reason that the number 
of teeth in the center wheel is the starting point in train 
calculations toward the escape wheel, while the center pinion 
is the starting point in calculations of the length of time the 
weight or spring is to drive the clock. Most writers on 
horology ignore this point, because it seems self-evident, 
but its omission has been the cause of much mystification 
to so many students that it is better to state it in plain terms, 
so that even temporary confusion may be avoided. 

Sometimes there is a second fixed point in a time train ; 
this occurs only when there is a seconds hand to be provided 
for; when this is the case the seconds hand must revolve 
once every minute. If it is a seconds pendulum the hand is 
generally carried on the escape wheel and the relation of 
revolutions between the hour and seconds wheels must then 
be as one is to sixty. This might be accomplished with a 
single wheel having sixty times as many teeth as the pinion 
on the seconds arbor ; but the wheel would take up so much 
room, on account of its large circumference, that the move- 
ment would become unwieldly because there would be no 
room, left for the other wheels; so it is cheaper to make 

264 



THE MODERN CLOCK. 265 

more wheels and pinions and thereby get a smaller clock. 
Now the best practical method of dividing this motion is by 
giving the wheels and pinions a relative velocity of seven 
and a half and eight, because 7.5 X 8 = 60. 

Thus if the center wheel has 80 teeth, gearing into a 
pinion of 10, the pinion will be driven eight times for each 
revolution of the center wheel, while the third wheel, with 
75 teeth, will drive its pinion of 10 leaves 7.5 times, so that 
this arbor will go 7.5 times eight, or 60 times as fast as the 
center wheel. 

If the clock has no seconds hand this second fixed point 
is not present in the calculations and other considerations 
may then govern. These are generally the securing of an 
even motion, with teeth of wheels and pinions properly 
meshing into each other, without incurring undue expense 
in manufacture by making too many teeth in the pinions 
and consequently in the wheels. For these reasons pinions 
of less than seven or more than ten leaves are rarely used 
in the common clocks, although regulators and fine clocks, 
where the depthing is important, frequently have 12, 14 or 
16 leaves in the pinions, as is also the case with tower clocks, 
where the increased size of the movement is not as impor- 
tant as a smoothly running train. Clocks without pendu- 
lums, carriage clocks, locomotive levers and nickel alarms, 
also have different trains, many of which have the six leaf 
pinion, with its attendant evils, in their trains. 

Weights. — Weights have the great advantage of driving 
a train with uniform power, which a spring does not ac- 
complish : They are therefore always used where exactness 
of time is of more importance than compactness or porta- 
bility of the clock. In making calculations for a weight 
movement, the first consideration is that as the coils of the 
cord must be side by side upon the barrel and each takes up 
a definite amount of space, a thicker movement (with longer 
arbors) will be necessary, as the barrel must give a suf- 



266 THE MODERN CI.OCK. 

ficient number of turns of the cord to run the clock the 
desired time and the length of the barrel, with the wheel and 
maintaining power all mounted upon the one arbor, will de- 
termine the thickness of the movement. If the clock is to 
have striking trains their barrels will generally be of more 
turns and consequently longer than the time barrel and in 
that case the distance between the plates is governed by 
the length of the longest barrel and its mechanism. 

The center wheel, upon the arbor of which sits the canon 
pinion with the minute hand, must, since the hand has to 
accomplish its revolution in one hour, also revolve once in 
an hour. When, therefore, the pinion of the center arbor 
has 8 leaves and the barrel wheel 144, then the 8 pinion 
leaves, which makes one revolution per hour, would require 
the advancing of 8 teeth of the barrel wheel, which is equal 
to the eighteenth part of its circumference. But when the 
eighteenth part in its advancing consumes i hour, then the 
entire barrel wheel will consume 18 hours to accomplish one 
revolution. If, now, 10 coils of the weight cord were laid 
around the barrel, the clock would then run 10 X 18 = 180 
hours, or 7^. days, before it is run down. 

Referring to what was said in a previous chapter on 
wheels being merely compound levers, it will be seen that 
as we gain motion we lose power in the same ratio. We 
shall also see that by working the rule backwards we may 
arrive at the amount of force exerted on the pendulum by 
the pallets. If we multiply the circumference of the escape 
wheel in inches by the number of its revolutions in one hour 
we will get the number of inches of motion the escape wheel 
has in one hour. Now if we multiply the weight by the 
distance the barrel wheel travels in one hour and divide by 
the first number we shall have the force exerted on the es- 
cape wheel. It will be simpler to turn the weight into grains 
before starting, as the division is less cumbersome. 

Another way is to find how many times the escape wheel 
revolves to one turn of the barrel and divide the weisrht 



THE MODERN CLOCK. 267 

by that number, which will give the proportion of weight 
at the escape wheel, or rather would do so if there were no 
power lost by friction. It is usual to estimate that three- 
quarters of the power is used up in frictions of teeth and 
pivots, so that the amount actually used for propulsion of 
the pendulum is very small, being merely sufficient to over- 
come the bending moment of the suspension spring and the 
resistance of the air. 

It is for this reason that clocks with finely cut trains and 
jeweled pivots, thus having little train friction, will run 
with very small weights. The writer knows of a Howard 
regulator with jeweled pivots and pallets running a 14- 
pound pendulum with a five-ounce driving weight. Of 
course this is an extreme instance and was the result of an 
experiment by an expert watchmaker who wanted to see 
what he could do in this direction. 

Usually the method adopted to determine the amount of 
weight that is necessary for a movement is to hang a small 
tin pail on the weight cord and fill it with shot sufficient to 
barely make the clock keep time. When this point has been 
determined, then weigh the pail of shot and make your driv- 
ing weight from eight to sixteen ounces heavier. In doing 
this be sure the clock is in beat and that it is the lack of 
power which stops the clock ; the latter point can be readily 
determined by adding or taking out shot from the pail until 
the amount of weight is determined. The extra weight is 
then added as a reserve power, to counteract the increase 
of friction produced by the thickening of the oil. 

Many clock barrels have spiral grooves turned in them 
to assist in keeping the coils from riding on each other, as 
where such riding occurs the riding coils are farther from 
the center of the barrel than the others, which gives them a 
longer leverage and greater power while they are unwinding, 
so that the power thus becomes irregular and affects the rate 
of the clock, slowing it if the escapement is dead beat and 
making it go faster if it is a recoil escapement. 



268 THE MODERN CLOCK. 

Clock cords should be attached to the barrel at the end 
which is the farthest from the pendulum, so that as they un- 
wind the weight is carried away from the pendulum. This 
is done to avoid sympathetic vibrations of the weight as it 
passes the pendulum, which interfere with the timekeeping 
when they occur. If the weight cannot be brought far 
enough away to avoid vibrations a sheet of glass may be 
drilled at its four corners and fixed with screws to posts 
placed in the back of the case at the point where vibration 
occurs, so that the glass is between the pendulum rod and 
the weight, but does not interfere with either. This looks 
well and cures the trouble. 

We have, heretofore, been speaking of weights which 
hang directly from the barrel, as was the case with the older 
clocks with long cases, so that the weight had plenty of 
room to fall. Where the cases are too short to allow of this 
method, recourse is had to hanging the weight on a pulley 
and fastening one end of the cord to the seat board. This 
involves doubling the amount of weight and also taking 
care that the end of the cord is fastened far enough from 
the slot through which it unwinds so that the cords will 
not twist, as they are likely to do if they are near together 
and the cord has been twisted too much while putting it on 
the barrel. Twisting weight cords are a frequent source of 
trouble when new cords have been put on a clock. The 
pulley is another source of trouble, especially if wire cords 
(picture cords) or cables are used. Wire cable should not 
be bent in a circle smaller than forty times its diameter if 
flexibility is to be maintained, hence pulleys which were all 
right for gut or silk frequently prove too small when wire 
is substituted and kinks, twisted and broken cables frequent- 
ly result from this cause. This is especially the case with 
the heavy weight of striking trains of hall and chiming 
clocks, where double pulleys are used, and also leads to 
trouble by jamming and cutting the cables and dropping 
of the weights in tower clocks where a new cable of larger 



THE MODERN CLOCK. 269 

size is used to replace an old one which has become unsafe 
from rust, or cut by the sheaves. 

Weight cords on the striking side of a clock should al- 
ways be left long enough so that they will not run down 
and stop before the time train has stopped. This is particu- 
larly the case with the old English hall clocks, as many of 
them will drop or push their gathering racks free of the 
gathering pinion under such conditions and then when the 
clock is wound it will go on striking continuously until the 
dial is taken off and the rack replaced in mesh with the gath- 
ering pinion. As clocks are usually wound at night, the 
watchmaker can see the disturbance that would be caused 
in a house in the "wee sma' hours" by such a clock going 
on a rampage and striking continuously. 

Oiling Cables.- — Clock cables, if of wire and small in 
size, should be oiled by dipping in vaseline thinned with 
benzine of good quality. Both benzine and vaseline must 
be free from acid, as if the latter is present it will attack the 
cable. This thinning will permit the vaseline to permeate 
the entire cable and when the benzine evaporates it will 
leave a thin film of vaseline over every wire, thus prevent- 
ing rust. Tower clock cables should be oiled with a good 
mineral oil, well soaked into them to prevent rusting. Gut 
clock cords, when dry and hard, are best treated with clock 
oil, but olive oil or sperm oil will also be found good to 
.soften and preserve them. New cords should always be 
oiled until they are soft and flexible. If the weight is under 
ten pounds silk cords are preferable to gut or wire as they 
are very soft and flexible. 

In putting on a new cable or weight cord the course of 
the weight and cord should be closely watched at all points, 
to see that they remain free and do not chafe or bind any- 
w^here and also that the coils run evenly and freely, side by 
side ; sometimes, especially with wire, a new cable gets 
kinked by riding^ the first time of winding: and is then very 



270 THE MODERN CLOCK. 

difficult to cure of this serious fault. Another point to 
watch is to see that the position of the cord when wound up 
will not cause an end thrust upon the barrel, which will in- 
terfere with the time keeping if it is overwound, so that the 
weight is jammed against the seatboard; this frequently 
happens with careless winding, if there is no stop work. 

To determine the lengths of clock cords or weights, we 
may have to approach the question from either end. If 
the clock be brought in without the cords, we first count 
the number of turns we can get on the barrel. This may be 
done by measuring the length of the barrel and dividing it 
by the thickness of the cord, if the barrel is smooth, or by 
counting the grooves if it be a grooved barrel. Next we 
caliper the diameter and add the thickness of one cord, which 
gives us the diameter of the barrel to the center of the 
cords, which is the real or working diameter. Multiply the 
distance so found by 3. 141 56, which gives the circumference 
of the barrel, or the length of cord for one turn of the bar- 
rel. Multiply the length of one turn by the number of turns 
and we have the length of cord on the barrel, when it is 
fully wound. If the cord is to be attached to the weight, 
measure the distance from the center of barrel to the bottom 
of the seat board and leave enough for tieing. If the weight 
is on a pulley it will generally require about twelve inches 
to reach from the barrel through the slot of the seat board, 
through the pulley to the point of fastening. 

To get the fall of the weight, stand it on the bottom of 
the case and measure the distance .from the top of the 
point of attachment to the bottom of the seat board. This 
will generally allow the weight to fall within two inches of 
the bottom and thus keep the cable tight when the clock runs 
down; thus avoiding kinks and over-riding when we wind 
again after allowing the clock to run down. If the weight 
has a pulley and double cord, measure from the top of the 
pulley to the seatboard, with the weight on the bottom, and 
then double this measurement for the length of the cord. 



THE MODERN CLOCK. 



71 



This measure is multiplied by as many times as there are 
pulleys in the case of additional sheaves. Striking trains 
are frequently run with two coils or layers of cord, on the 
barrel, time trains never have but one. 

Now, having the greatest available length of cord deter- 
mined according either of the above conditions, we can de- 
termine the number of turns for which we have room on 
our barrel and divide the length of cord by the number of 
turns. This will give us the length of one turn of the cord 
on our barrel and thus having found the circumference it is 
easy to find the diameter which we must give our barrel in 
suiting a movement to given dimensions of the case. This 
is frequently done where the factory may want a movement 
to fit a particular style and size of case which has proved 
popular, or when a watchmaker desires to make a movement 
for which he has, or will buy, a case already made. 

As to tower clock cables, getting the length of cable on 
the barrel is, of course, the same as given above, but the 
rest of it is an individual problem in every case, as cables 
are led so differently and the length of fall varies so that 
only the professional tower clock men are fitted to make 
the measurements for new work and they require no in- 
struction from me. It might be well to add, however, that 
in the tower clocks by far the greater part of the cable is 
always outside the clock and only the inner end coils and 
uncoils about the barrel. It is for this reason that the outer 
ends of the cables are so generally neglected by watchmakeri' 
in charge of tower clocks and allowed to cut and rust until 
they drop their weights. Caretakers of tower clocks should 
remember that the inner ends of cables are always the best 
ends ; the parts that need watching are those in the sheaves 
or leading to the sheaves. Tower clocks should have the 
cables marked where to stop to prevent overwinding. 

In chain drives for the weights of cuckoo and other clocks 
with exposed weights, we have generally a steel sprocket 
wheel with convex guiding surfaces each side of the 



272 THE MODERN CLOCK. 

sprocket and projecting flanges each side of the guides; one 
of these flanges is generally the ratchet wheel. The ratchet 
wheel, guide, sprocket, guide and flange, form a built-up 
wheel which is loose on the arbor and is pinned close to the 
great wheel, which is driven by a click on the wheel working 
into the ratchet of the drive. It must be loose on the arbor, 
because the clock is wound by pulling the sprocket and 
ratchet backward by means of the chain until the weight is 
raised clear up to the seat board. There are no squares on 
the arbors, w^hich have ordinary pivots at both ends, and 
the great wheel is fast on the arbor. The diameter of the 
convex portion of the wheel each side of the sprocket is the 
diameter of the barrel, and the chain should fit so that alter- 
nate links will fit nicely in the teeth of the sprocket ; where 
this is not the case they will miss a link occasionally and the 
weight will then fall until the chain catches again, when it 
will stop with a jerk; bent or jammed links in the chain will 
do the sam?i thing. Sometimes a light chain on a heavy 
weight will stretch or spread the links enough to make their 
action faulty. If examination shows a tendency to open the 
links, they should be soldered; if they are stretching, a 
heavier chain of correct lengths of links should be substi- 
tuted. Twisted chains are another characteristic fault and 
are usually the result of bent or jammed links. A close 
examination of such a chain will generally reveal several 
links in succession which are not quite flat and careful 
straightening of these links will generally cure the tendency 
to twist. 

Mainsprings for Clocks. — There are many points of 
difference between mainsprings for clocks and those for 
watches. They differ in size, strength, number of coils and 
in their eflfect on the rates of the clock. 

Watch springs are practically all for 30-hour lever es- 
capements, with a few cylinder, duplex and chronometer 
escapements. If a fusee watch happens into a shop nowa- 



THE MODERN CLOCK. 



273 



days it is so rare as to be a curiosity worth stopping work 
to look at. 

The clocks range all the way from 30 hours to 400 days in 
length of time between windings and include lever, cylinder, 
duplex, dead beat, half dead beat, recoil and other escape- 
ments. Furthermore some of these, even of the same form 
of escapements, will vary so in weight and the consequent 
influence of the spring that what will pass in one case will 
give a wildly erratic rate in another instance. Many of the 
small French clocks have such small and light pendulums 
that very nice management of the stop works is necessary 
to prevent the clock from gaining wildly when wound or 
stopping altogether when half run down. 

Nothing will cause a clock with a cylinder escapement 
to vary in time more than a set or gummy m.ainspring, for 
it will gain time when first wound and lose when half run 
down, or when there is but little power on the train. In 
such a case examine the mainspring and see that it is neither 
gummy nor set. If it is set, put in a new spring and you can 
probably bring it to time. 

With a clock it depends entirely on the kind of escape- 
ment that it contains, w^hether it runs fastei or slower, with 
a stronger spring; if you put a stronger mainspring in a 
clock that contains a recoil escapement the clock will gain 
time, because the extra power, transmitted to the pallets will 
cause the pendulum to take a shorter arc, therefore gain 
time, where the reverse occurs in the dead-beat escapement. 
A stronger spring will cause the dead-beat pendulum to take 
a longer arc and therefore lose time. 

If a pendulum is short and light these effects will be much 
greater than with a long and heavy pendulum. 

At all clock factories they test the mainsprings for power 
and to see that they unwind evenly ; those that do are marked 
No. I, and those that do not are called ''seconds." The sec- 
onds are used only for the striking side of the clocks, while 
the perfect ones are used for the running, or time side. 



274 



THE MODERN CLOCK. 



Sometimes, however, a seconds' spring will be put on the 
time side and will cause the clock to vary in a most erratic 
way. This changing of springs is very often done by care- 
less or ignorant workmen in cleaning and then they cannot 
locate the trouble. 

All mainsprings for both clocks and watches should be 
smooth and well polished. Proper attention to this one item 
will save many dollars' worth of time in examining move- 
ments to try to detect the cause of variations. 

A rough mainspring (that is, an emery finished main- 
spring) will lose one-third of its power from coil friction, 
and in certain instances even one-half. The deceptive fea- 
ture about this to the watchmaker is that the clock will take 
a good motion with a rough spring fully found, but v/ill fall 
off when partly unwound, and the consequence is that he 
finds a good motion when the spring is put in and w^ound, 
and he afterward neglects to examine the spring w^hen he 
examines the rate as faulty. The best springs are cheap 
enough, so that only the best quality should be used, as it 
is easy for a watchmaker to lose three or four dollars' worth 
of time looking for faults in the escapement, train and ev- 
erywhere else, except the barrel, when he has inserted a 
rough, thick, poorly made spring. The most that he can 
save on the cheaper qualities of springs is about five cents 
per spring and we will ask any watchmaker how long it 
would take to lose five cents in examination of a movement 
to see what is defective. 

Here is something which you can try yourself at the 
bench. Take a rough watch mainspring; coil it small 
enough to be grasped in the hand and then press on the 
spring evenly and steadily. You will find it difficult to make 
the coils slide on one another as the inner coils get smaller ; 
they will stick together and give way by jerks. Now open 
your hand slowly and you will feel the spring uncoiling in 
an abrupt, jerky way, sometimes exerting very little pressure 
on the hand, at other times a great deal. A dirty, gummy 



THE MODERN CLOCK. 



275 



spring will do the same thing. Now take a clean, well pol- 
ished spring and try it the same way ; notice how much more 
even and steady is the pressure required to move the coils 
upon each other, either in compressing or expanding. Now 
oil the well polished spring and try it again. You will find 
you now have something that is instantly responding, evenly 
and smoothly, to every variation of pressure. You can also 
compress the spring two or three turns farther with the 
same force. This is what goes on in the barrel of every 
clock or watch; you have merely been using your hand as 
a barrel and feeling the action of the springs. 

Now a well finished mainspring that is gummy is as ir- 
regular in its action as the worst of the springs described 
above, yet very few watchmakers will take out the springs 
of a clock if they are in a barrel. One of them once said to 
me, "Why, who ever takes out springs? I'll bet I clean a 
hundred clocks before I take out the springs of one of 
them!" Yet this same man had then a clock which had 
come back to him and which was the cause of the conver- 
sation. 

There must be in this country over 25,000 fine French 
clocks in expensive marble or onyx cases, which were given 
as wedding presents to their owners, and which have never 
run properly and in many instances cannot be made to run 
by the watchmakers to whom they were taken when they 
stopped. Let me give the history of one of them. It was an 
eight-day French marble clock which cost $25 (wholesale) 
in St. Louis and was given as a wedding present. Three 
months later it stopped and was taken to a watchmaker well 
known to be skillful and who had a fine run of expensive 
watches constantly coming to him. He cleaned the clock, 
took it home and it ran three hours ! It came back to him 
three times; during these periods he went over the move- 
ment repeatedly ; every wheel was tested in a depthing tool 
and found to be round : all the teeth were examined sepa- 
rately under a glass and found to be perfect; the pinions 



276 T'lE MODERN CLOCK. 

were subjected to the same careful scrutiny; the depthings 
were tried with each wheel and pinion separately ; the pivots 
were tested and found to be right; the movement was put 
in its case and examined there; it would run all right on 
the watchmaker's bench/ but not in the home of its owner. 
It would stop every time it was moved in dusting the man- 
tel. He became disgusted and took the clock to another 
watchmaker, a railroad time inspector; same results. In 
this way the clock moved about for three years ; whenever 
the owner heard of a man who was accounted more than 
ordinarily skillful he took him the clock and watched him 
''fall down" on it. Finally it came into the hands of an 
ex-president of the American Horological Society. He 
made it run three weeks. When he found the clock had 
stopped again he refused pay for it. Three months later he 
called and got the clock, kept it for three weeks, brought it 
back without explanation and lo, the clock ran! It would 
even run considerably out of beat! When asked what he 
had done to the clock, he merely laughed and said "Wait.'* 

A year later the clock was still going satisfactorily and he 
explained. "That was the first time I ever got anything I 
couldn't fix and it made me ashamed. I kept thinking it 
over. Finally one night in bed I got to considering why a 
clock wouldn't run when there was nothing the matter with 
it. The only reason I could see was lack of power. Next 
morning I got the clock and put in new mainsprings, the best 
I could find. The clock was cured ! None of these other 
men who had the clock took out the springs. They came 
to me all gummed up, while the rest of the clock was clean, 
bright and in perfect order, I cleaned the springs and re- 
turned the clock ; it ran three weeks. When I took it back 
I put in stronger springs, because I found them a little soft 
on testing them. If any of your friends have French clocks 
that won't go, send them to me." 

Three-quarters of the trouble with French clocks is in 
the spring box; mainspring too weak, gummy or set; stop 



THE MODERN CLOCK. 277 

works not properly adjusted, or left off by some numskull 
who thought he could make the clock keep time without it 
when the maker couldn't; mainspring rough, so that it un- 
coils by jerks ; spring too strong, so that the small and light 
pendulum cannot control it. These will account for far 
more cases than the ''flat wheel" story that so often comes 
to the front to account for a failure on the part of the work- 
man. Of course he must say something to his boss to ac- 
count for his failure and the ''wheels out of round" and 
*'.the faulty depthing" have been standard excuses for French 
clocks for a century. Of course they do occur, but not 
nearly as often as they are credited with, and even then such 
a clock may be made to perform creditably if the springs 
are right. 

Another source of trouble is buckled springs, caused by 
some workman taking them out or putting them in the bar- 
rel without a mainspring winder. There are many men 
who will tell you that they never use a winder; they can 
put any spring in without it. Perhaps they can, but there 
comes a day when they get a soft spring that is too wide for 
this treatment and they stretch one side of it, or bend, or 
kink it, and then comes coil friction with its attendant evils. 
These may not show with a heavy pendulum, but they are 
certain to do so if it happens to be an eight-day movement 
with light pendulum or balance, and this is particularly true 
of a cylinder. 

All springs should be cleaned by soaking in benzine or 
gasoHne and rubbing with a rag until all the gum is ofi^ 
them before they are oiled. Heavy springs may be wiped 
by wrapping one or two turns of a rag around them and 
pushing it around the coils. The spring should be well 
cleaned and dried before oiling. A quick way of cleaning 
is to wind the springs clear up; stick a peg in the escape 
wheel ; remove the pallet fork ; plunge the whole movement 
into a pail of gasoline large enough to cover it ; let it stand 
until the gasoline has soaked into the barrels; remove the 



278 THE MODERN CLOCK. 

peg and let the trains run down. The coils of the spring 
will scrub each other in unwinding; the pivots will clean 
the pivot holes and the teeth of wheels and pinions will clean 
each other. Then take the clock apart for repairs. Springs 
which are not in barrels should be wound up and spring 
clamps put on them before taking down the clock. About 
six sizes of these clamps (from 2^ inches to ^ inch) are 
sufficient for ordinary work. 

Rancid oilis also the cause of many "come-backs." Work- 
men will buy a large bottle of good oil and leave it standing 
uncorked, or in the sun, or too near a stove in winter time, 
until it spoils. Used in this condition it will dry or gum in 
a month or two and the clock comes back, if the owner is 
particular; if not, he simply tells his friends that you can't 
fix a clock and they had better go elsewhere with their 
watches. 

For clock mainsprings, clock oil, such as you buy from 
material dealers, is recommended, provided it is intended 
for French mainsprings. If the "lubricant is needed for 
coarse American springs, mix some vaseline with refined 
benzine and put it .on hberally. The benzine will dissolve 
the vaseline and will help to convey the lubricant all over 
the spring, leaving no part untouched. The liquid will then 
evaporate, leaving a thin coating of vaseline on the spring. 

It is best to let springs dow^n with a key made for the 
purpose. It is a key with a large, round, wooden handle, 
which fills the hand of the watchmaker when he grasps it. 
Placing the key on the arbor square, with the movement 
►held securely in a vise, wind the spring until you can "re- 
lease the click of the ratchet with a screwdriver, wire or 
other tool; hold the click free of the ratchet and let the 
handle of the key turn slowly round in the hand until the 
spring is down. Be careful not to release the pressure on 
the key too much, or it will get away from you if the spring 
is strong, and will damage the movement. This is why the 
handle is made so large, so that you can hold a strong 
spring. 



THE MODERN CLOCK. 279 

It is of great importance, if we wish to avoid variable 
coil friction, that the spring should wind, from the very 
starting, concentrically ; i. e., that the coils should commence 
to wind in regular spirals, equidistant from each other, 
around the arbor. In very many cases we find, when we 
commence to wind a spring, that the innermost coil bulges 
out on one side, causing, from the very beginning, a greater 
friction of the coils on that side, the outer ones pressing 
hard against it as you continue to wind, while on the outer 
side of the arbor they are separated from each other by 
quite a little space betw^een them, and that this bulge in the 
first coil is overcome and becomes concentric to the arbor 
only after the spring is more than half way wound up. Thia 
necessarily produces greater and more variable coil friction. 
When a spring is put into the barrel the innermost coil 
should come to the center around the arbor by a gradual 
sweep, starting from at least one turn around away irom 
the other coils. Instead of that, we more often find it lay- 
ing close to the outer coils to the very end, and ending 
abruptly in the curl in the soft end that is to be next the 
arbor. When this is the case in a spring of uniform thick- 
ness throughout, it is mainly due to the manner of first 
winding it from its straight into a spiral form. To obviate 
it, I generally wind the first coils, say tw^o or three, on a 
center in the winder, a trifle smaller than the regular one, 
which is to be of the same diameter of the arbor center in 
the barrel. You will find that the substitution of the regu- 
lar center, afterwards, will not undo the extra bending thus 
produced on the inner coils, and that the spring will abut 
by a more gradual sw^eep at the center, and wind more con- 
centrically. 

The form of spring formerly used with a fusee in Eng- 
lish carriage clocks and marine chronometers is a spring 
tapering slightly in thickness from the inner end for a dis- 
tance of two full coils, the thickness increasing as we move 
away from the end, then continuing of uniform thickness 



28o THE MODERN CLOCK. 

until within about a coil and a half from the other end, 
when it again increases in thickness by a gradual taper. 
The increase in the thickness towards the outer end will 
cause it to cling more firmly to the wall of the barrel. The 
best substitute for this taper on the outside is a brace added 
to some of the springs immediately back of the hole. With 
this brace, and the core of the winding arbor cut spirally, 
excellent results are obtained with a spring of uniform thick- 
ness throughout its entire length. Something, too, can be 
done to improve the action of a spring that has no brace, 
l)y hooking it properly to the barrel. The hole in the spring 
on the outside should never be made close to the end ; on the 
contrary, there should be from a half to three-quarters of an 
inch left beyond the hole. This end portion will act as a 
brace. 

When the spring is down, the innermost coil of it should 
form a gradual spiral curve towards the center, so as to 
meet the arbor without forcing it to one side or the other. 
This curve can be improved upon, if not correct, with suit- 
ably shaped pliers; or it can be approximated by winding 
the innermost coils first on an arbor a little smaller in diam- 
eter than the barrel arbor itself. 

Another and very important factor in the development of 
the force of the spring is the proper length and thickness 
of it. For any diameter of barrel there is but one length 
and one thickness of spring that will give the maximum 
number of turns to wind. This is conditioned by the fact 
that the volume w^hich the spring occupies when it is down 
must not be greater nor less than the volume of the empty 
space around the arbor into which it is to be wound, so that 
the outermost coil of the spring when fully wound will oc- 
cupy the same place which the innermost occupies when it 
is down. In a barrel, the diameter of whose arbor is one- 
third that of the barrel, the condition is fulfilled when the 
measure across the coils of the spring as it lays against the 
wall of the barrel, is 0.39 of the empty space, or, taking the 



THE MODERN CLOCK. 281 

diameter of the barrel as a comparison, 0.123 of the latter; 
in other words, nearly one-eighth of the diameter of the 
barrel. This is the width that will give the greatest number 
of turns to wind, whatever may be the length or thickness 
of any spring. If now we desire a spring to wind a given 
number of turns, there is but one thickness and one length 
of it that will permit it to do so. The thickness remaining 
the same, if we make the spring longer or shorter, we re- 
duce the number of turns it will wind; more rapidly by 
making it shorter, less so by making it longer. It is there- 
fore not only useless, but detrimental, to put into a barrel 
a greater number of coils, or turns, than are necessary, not 
only because it will reduce the number of turns the barrel 
will wind, but it will produce greater coil friction by filling 
up the space with more coils than are necessary. 

A mainspring in the act of uncoiling in its barrel always 
gives a number of turns equal to the difference between the 
number of coils in the up and the down positions. Thus, if 
17 be the number of coils when the spring is run down, and 
25 the number when against the arbor, the number of turns 
in uncoiling will be 8, or the difference between 17 and 2^. 

The cause of breakage is usually, that the inner coils are 
put to the greatest strain, and then the slightest flaw in the 
steel, a speck of rust, grooves cut in the edges of the spring 
by allowing a screwdriver to slip over them, or an unequal 
effect of change of temperature, causes the fracture, and 
leaves the spring free to uncoil itself with verv great rapid- 
ity. 

Now this sudden uncoiling means that the whole energy 
of the spring is expended on the barrel in a very small frac- 
tion of a second. In reality the spring strikes the inner side 
of the rim of the barrel, a violent blow in the direction the 
spring is turning, that is, backwards ; this is due to the 
mainspring's inertia and its very high mean velocity. The 
velocity is nothing at the outer end, where the spring is 
fixed, but rises to the maximum at the point of fracture, and 



282 THE MODERN CLOCK. 

the kinetic energy at various points of the spring could no 
doubt be calculated mathematically or otherwise. 

For instance, take a going barrel spring of eight and a 
half turns, breaking close up to the center while fully wound. 
A 'point in the spring at the fracture makes eight turns in 
the opposite direction to which it was wound, a point at the 
middle four turns, and a point at the outer end nothing, an 
effect similar to the whole mass of the spring making four 
turns backwards. At its greatest velocity it is suddenly 
stopped by the barrel, wheel teeth engaging its pinion; this 
stoppage or collision is what breaks center pinions, third piv- 
ots, wheel teeth, etc., unless their elasticity, or some inter- 
posed contrivance, can safely absorb the stored-up energy 
of the mainspring, the spring being, as every one knows, 
the heaviest moving part in an ordinary clock, except where 
the barrel is exceptionally massive. 

Stop Works. — Stop works are devices that are but little 
understood by the majority of workmen in the trade. They 
are added to a movement for either one or both of two dis- 
tinct purposes: First, as a safety device, to prevent injury 
to the escape wheel from over winding, or to prevent undue 
force coming on the pendulum by jamming the weight 
against the top of the seat board and causing a variation in 
time in a fine clock; or, second, to use as a compromise by 
utilizing only the middle portion of a long and powerful 
spring, which varies too much in the amount of its power 
in the up and down positions to get a good rate on the 
clock if all the force of the spring were utilized in driv- 
ing the movement. 

With weight clocks, the stop work is a safety device and 
should always be set so that it will stop the winding when 
the barrel is filled by the cord ; consequently the way to set 
them is to wind until the barrel is barely full and set the 
stops with the fingers locked so as to prevent any further 
action of the arbor in the direction of the windincr and the 



THE MODERN CLOCK. 283 

cord should then be long enough to permit the weight to be 
free. Then unwind until within half a coil of the knot in 
the cord where it is attached to the barrel and see that the 
weight is also free at the bottom of the case, when the stops 
again come into action. This will allow the full capacity 
of the barrel to be used. 

When stop work is found on a spring barrel, it may be 
taken for granted that the barrel contains more spring than 
is being wound and unwound in the operation of the clock 
and it then becomes important to know how many coils are 
thus held under tension, so that wc may put it back .cor- 
rectly after cleaning. Wind up the spring and then let it 
slowly down with the key until the stop work is locked, 
counting the number of turns, and writing it down. Then 
hold the spring with the letting down key and take a screw 
driver and remove the stop from the plate ; then count the 
number of turns until the spring is down and also write 
that down. Then take out the spring and clean it. You 
may find such a spring will give seventeen turns in the bar- 
rel without the stop work on, while it will give but ten with 
the stop work; also that the arbor turned four revolutions 
after you removed the stop. Then the spring ran the clock 
from the fourth to the fourteenth turns and there were 
four coils unused around the arbor, ten to run the clock and 
three unused at the outer end around the barrel. This 
would indicate a short and light pendulum or balance, which 
is very apt to be erratic under variations of power, and if 
the rate was complained of by the customer you can look 
for trouble unless the best adjustment of the spring is se- 
cured. Put the spring back by winding the four turns and 
putting on the stop work in the locked position ; then wind. 
If the clock gains when up and loses when down, shift the 
stop works half a turn backwards or forwards and note the 
result, making changes of the stop until you have found 
the point at which there is the least variation of power in 
the up and down positions. If the variation is still too great 
a thinner spring must be substituted. 



284 THE MODERN CLOCK. 

There are several kinds of stop work, the most common 
being what is known as the Geneva stop, a Maltese cross 
and a finger such as is commonly seen on watches. For 
watches they have five notches, but for clocks they are 
made with a greater number of notches, according to the 
number of turns desired for the arbor. The finger piece is 
mounted on a square on the barrel arbor and the star wheel 
on the stud on the plate. In setting them see that the finger 
is in line with the center of the star wheel when the stop is 
locked, or they will not work smoothly. 

There is another kind of stop work which is used in some 
American clocks, and as there is no friction with it, and no 
fear of sticking, nor any doubt of the certainty of its action, 
it is perhaps the most suitable for regulators and other fine 
clocks which have many turns of the barrel in winding. 
This stop is simple and sure. It consists of a pair of wheels 
of any numbers with the ratio of odd numbers as 7 and 6, 
9 and 10, 15 and 16, 30 and 32, 45 and 48, etc. ; the smaller 
wheel is squared on the barrel arbor and the larger mounted 
on a stud on the plate. These wheels are better if made 
with a larger number of teeth. On each wheel a finger is 
planted, projecting a little beyond the outsides of the wheel 
teeth, so that when the fingers meet they will butt securely. 
The meeting of these fingers cannot take place at every 
revolution because of the difference in the numbers of the 
teeth of the wheels ; they will pass without touching every 
time till the cycle of turns is completed, as one wheel goes 
round say sixteen times while the other goes fifteen, and 
when this occurs the fingers will engage and so stop fur- 
ther winding. When the clock has run down sixteen turns 
of the barrel the fingers will . again meet on the opposite 
side, and so the barrel will be allowed to turn backwards 
and forwards for sixteen revolutions, being stopped by the 
fingers at each extreme. When in action the fingers may 
butt either at a right or an obtuse angle, only not too obtuse, 
as this would put a strain on, tending to force the wheels 



THE MODERN CLOCK. 



apart. If preferred the fingers may be made of steel, but 
this is not necessary. 

Maintaining Powers. — x\stronomical clocks, watch- 
maker's regulators and tower clocks arc, or at least should 
be, fitted with maintaining power. A good tower clock 
should not vary in its rate more than five to ten seconds a 
week. Many of them, when favorably situated and care- 
fully tended, do not vary over five to ten seconds per month. 
It requires from five to thirty minutes to wind the time 
trains of these clocks and the reader can easily see where 




Fig. 83 

the rate would go if the power were removed from the pen- 
dulum for that length of time ; hence a maintaining power 
that will keep nearly the same pressure on the escape wheel 
as the weight does, is a necessity. Astronomical clocks and 
fine regulators have so little train friction, especially if jew- 
eled, that when the barrel is turned backwards in winding 
the friction between the barrel head and the gr^at wheel is 
sufficient to stop the train, or even run it backwards, injur- 
ing the escape wheel and, of course, destroying the rate of 
the clock; therefore they are provided with a device that 
will prevent such an occurrence. Ordinary clocks do not 
have the maintaining power because only the barrel arbor 
is reversed in winding, and that reversal is never for more 
than half a turn at a time, as the power is thrown back on 
the train every time the winder lets go of the key to turn 
his hand over for another grip. 



286 



THE MODERN CLOCK. 



Figs. 83, 84 and 85 show the various forms of main- 
taining powers, which differ only in their mechanical de- 
tails. In all of them the maintaining power consists of two 
ratchet wheels, two clicks and either one or two springs ; 
the springs vary in shape according to whether the great 
wheel is provided with spokes or left with a web. If the 
great wheel has spokes the springs are attached on the out- 
side of the large ratchet wheel so that they will press on 
opposite spokes of the great wheel and are either straight, 
curved or coiled, according to the taste of the maker of the 
clock and the amount of room. If made with a web a cir- 





Fig. 84 



cular recess is cut in the great wheel, see Fig. 83, wide and 
deep enough for a single coil of spring wire which has its 
ends bent at right angles^ to the plane of the spring and one 
end slipped in a hole of the ratchet and the other in a sim- 
ilar hole in the recess of the great wheel. A circular slot 
is cut at some portion of the recess in the great wheel 
where it will not interfere with the spring and a screw in 
the ratchet works back and forth in this slot, limiting the 
action of the spring. Stops are also provided for the spokes 
of the great wheel in the case of straight, curved or coiled 
springs, Figs. 84 and 85. These stops are set so as to give 



THE MODERN CLOCK. 2S7 

an angular movement of two or three teeth of the great 
wheel in the case of tower clocks and from six to eight 
teeth in a regulator. The springs should exert a pressure 
on the great wheel of just a little less than the pull of the 
weight on the barrel ; they will then be compressed all the 
time the weight is in action, and the stops will then transmit 
the power from the large ratchet to the great wheel, which 
drives the train. Both the great wheel and the large rat- 
chet wheel are loose on the arbor, being pinned close to the 
barrel, but free to revolve. A smaller ratchet, having its 




Fig. 85 

teeth cut in the reverse direction from those of the larger 
one, is fast to the end of the barrel. A click, called the 
winding click, on the larger ratchet acts in the teeth of the 
smaller one during the winding, holding the two ratchets 
together at all other times. A longer click, called the de- 
tent click, is pivoted to the clock plate, and drags idly over 
the teeth of the larger ratchet while the clock is being 
driven by the weight and the maintaining springs are com- 
pressed. When the power is taken off by the reversal of 
the barrel in winding, the friction between the sides of the 
two ratchets and great wheel would cause them to also turn 
backward, if it wevQ not for this detent click. W'ith its end 
fast to the plate, which drops into the teeth of the large 
ratchet and prevents it from turning backward. We now 
have the large ratchet held motionless by the detent click 
on the clock plate and the compressed springs which are 



288 



THE MODERN CLOCK. 



carried between the large ratchet and the great wheel will 
then begin to expand, driving the loose great wheel until 
their force has been expended, or until winding is com- 
pleted, when they will again be compressed by the pull of 
th-e weight. In some tower clocks curved pins are fixed to 
opposite spokes of the great wheel and coiled springs are 
wound around the pins. Fig. 85 ; eyes in the large ratchet 
engage the outer ends of the pins and compress the springs. 
The clicks for maintaining powers should not be short, 
and the planting should be done so that lines drawn from 
the barrel center to the click points and from the click cen- 
ters to the points, will form an obtuse angle, like B, Fig. 86. 




Fig. 



giving a tendency for the ratchet tooth to draw the click 
towards the barrel center. The clicks should be nicely 
formed, hardened and tempered and polished all over with 
emery. Long, thin springs will be needed to keep the wind- 
ing clicks up to the ratchet teeth. The ratchet wheel must 
run freely on the barrel arbor, being carried round by the 
clicks while the clock is going, and standing still while the 
weight is being wound up. It is retained at this time by a 
long detent click mounted on an arbor having its pivots 
fitted to holes in the clock frame. The same remark as to 
planting applies to this click as well as the others, and to all 



THE MODERN CLOCK. 



289 



clicks having similar objects; but as this chck has its own 
weight to cause it to fall no spring is required. To pre- 
vent it lying heavily on the wheel, causing wear, friction 
and a diminution of driving power, it is as well to have it 
made light. There is no absolute utility in fixing the click 
to its collet with screws, but if done, it can be taken off 
to be polished, and the appearance will be more workman- 
like. This click should have its point hardened and tem- 
pered, as there is considerable wear on it. 

If the great wheel has spokes the best form for the two 
springs for keeping the train going whilst being wound 
is that of the letter U, as shown to the left of Fig. 84, one 
end enlarged for the screw and steady pin and the blade 
tapering all along towards the end which is free. The 
springs may be made straight and bent to the form while 

n 




Fig. 87 

soft, then hardened and tempered to a full blue. They are 
best when as large as the space between two arms of the 
main wheel will allow. When screwed on the large ratchet 
the backs of both should bear exactly against the respective 
arms of the mainwheel, and a pair of pins is put in the 
ratchet, so that any opposite pair of the mainwheel arms 
may rest upon them when the springs are set up by the 
clock weight. The strength of the springs can be ad- 
justed by trial, reducing them till the weight of the clock 
sets them up easily to the banking pins. 

There are two methods of keeping the loose wheels 
against the end of the barrel, while allowing them to turn 
freely during winding ; one is a sliding plate with a keyhole 
slot, Fig. 87, to slip in a groove on the arbor, as is generally 
adopted in such house clocks as have fuzees, as well as on 



290 THE MODERN CLOCK. 

the barrels of old-fashioned weight clocks; the other is a 
collet exactly the same as on watch fuzees. They are both 
sufficiently effective, but perhaps the latter is the best of the 
two, because the collet may be fitted on the arbor with a 
pipe, and being turned true on the broad inside face, gives 
a larger and steadier surface for the mainwheel to work 
against, whereas the former only has a small bearing on the 
shoulder of the small groove in the arbor, which fitting is 
Hable to wear and allow the main and the other loose wheel 
to wobble sideways, displacing the contact with the detent 
click and causing the mainwheel to touch the collet of the 
center wheel if very near together ; so, on the whole, a col- 
let, as on a watch fuzee, seems the better arrangement, 
where there is plenty of room for it on the arbor. 

There is an older form of maintaining power which is 
sometimes met with in tower clocks and which is sometimes 
imitated on a small scale by jewelers who are using a cheap 
regulator and wish to add a maintaining power where there 
is no room between the barrel and plates for the ratchets 
and great wheel. 

The maintaining power. Fig. 88, consists of a shaft. A, a 
straight lever, B, a segment of a pinion, C, a curved, double 
lever, D, a weight, E. The shaft, A, slides endwise to en- 
gage the teeth of the pinion segment with the teeth of the 
great wheel. No. 2, the straight lever has a handle at both 
ends to assist in throwing the pinion out or in and a shield 
at the outer end to cover the end of the winding shaft. No. 
3, when the key is not on it. 

The curved lever is double, and the pinion segment turns 
loosely between the halves and on the shaft, A ; it is held 
up in its place by a light spring, F; the weight, E, is also 
held between the two halves of the double lever. 

The action is as follows : The end of the lever, B, covers 
the end of the winding shaft so that it is necessary to raise 
it before putting the key on the winding shaft; it is raised 
till it strikes a stop, and then pushed in till the pinion seg- 



THE MODERN CLOCK, 



291 




Fig. 88. Maintaining Power. 



292 THE MODERN CLOCK. 

ment engages with the going wheel of the train, when the 
weight, E, acting through the levers, furnishes power to 
drive the clock-train while the going weight is being wound 
up. Of course the weight on the maintaining power must 
be so proportioned to the leverage that it will be equal to 
the power of the going barrel and its weight, a simple prop- 
osition in mechanics. 

The number of teeth on the pinion segment, C, is suffi- 
cient to maintain power for fifteen minutes, at the end of 
which time the lever, B, will come down and again cover 
the end of the winding shaft ; or, it may be pumped out of 
gear and dropped down. In case it is forgotten, the spring, 
F, will allow the segment to pass out of gear of itself and 
will simply allow it to give a click as it slips over each 
tooth in the going wheel ; if this were not provided for, it 
would stop the clock. 



CHAPTER XVI. 

MOTION WORK AND STRIKING TRAINS. 

Motion work is the name given to the wheels and pinions 
used to make the hour hand go once around the dial while 
the minute hand goes twelve times. Here a few prelimi- 
nary observations will do much toward clearing up the 
operations of the trains. The reader will recollect that we 
started at a fixed point in the time train, the center arbor 
which must revolve once per hour, and increased this mo- 
tion by making the larger wheels drive the smaller (pin- 
ions) until we reached sixty or more revolutions of the 
escape wheel to one of the center arbor. This gearing to 
increase speed is called "gearing up" and in it the pinions 
are always driven by the wheels. In the case of the hour 
hand we have to obtain a slowing effect and we do so by 
making the smaller wheels (pinions) drive the larger ones. 
This is called "gearing back" and it is the only place in 
the clock where this method of gearing occurs. 

We drew attention to a common usage in the gearing up 
of the time trains — ^that of making the relations of the 
wheels and pinions 8 to one and 7.5 to one ; 7.5 X 8 = 60. 
So we find a like usage in our motion work, viz., 3 to one 
and 4 to one ; 3X4=12. Say the cannon pinion has 
twelve teeth; then the minute wheel generally has 36, or 
three to one, and if the minute wheel pinion has 10, the 
hour wheel will have 40, or four to one. Of course, any 
numbers of wheels and pinions may be used to obtain the 
same result, so long as the teeth of the wheels multiplied 
together give a product which is twelve times that of the 
pinions multiplied together ; but three and four to one have 

293 



294 "^^^ MODERN CLOCK. 

been settled upon, just as the usage in the train became 
fixed, and for the same reasons; that is, these proportions 
take up the least room and may be made with the least 
material. Also, the pinion with the greatest number of 
teeth, being the larger, is usually selected as the cannon 
pinion, as it gives more room to be bored out to receive the 
cannon, oi* pipe. If placed outside the clock plate, the min- 
ute wheel and pinion revolve on a stud in the clock plate: 
but if placed between the frames, they are mounted on 
arbors like the other w^heels. The method of mounting is 
merely a matter of convenience in the arrangement of the 
train and is varied according to the amount of room in the 
movement, or convenience in assembling the movement at 
the factory, little attention being paid to other considera- 
tions. 





o 



fc 



Fig. 89. Fig. 90. 

The cannon pinion is loose on the center arbor and be- 
hind it is a spring, called the center spring, or ''friction," 
Figs. 89 and 90, which is a disc that is squared on the arbor 
at its center and presses at three points on its outer edge 
against the side of the cannon pinion; or it may be two or 
three coils of brass wire. This center spring thus produces 
friction enough on the cannon to drive it and the hour 
hand, while permitting the hands to be turned backward or 
forward without interfering with the train. In French man- 
tel clocks the center spring is dispensed with and a portion 
of the pipe is thinned and pressed in so as to produce k 



THE MODERN CLOCK. 



295 



friction between the pipe and the center arbor which is 
sufficient to drive the hands ; this is similar to the friction 
of the cannon pinion in a watch. 

In some old English house clocks w^ith snail strike, the 
cannon pinion and minute wheel have the same number of 
teeth for convenience in letting off the striking work by 
means of the minute wheel, which thus turns once in an 
hour. Where this is the case the hour wheel and its pinion 






^^\ 
7/N^- 






I 





Fig. 91. 



bear a proportion to each other of twelve to one; usually 
there is a pinion of six leaves engaging a wheel of ^2 teeth, 
or seven and eighty-four are sometimes found. 

In tower clocks, where the striking is not discharged by 
the motion w'ork, the cannon pinion is tight on its arbor 
and the motion work is similar to that of watches. See 
Fig. 91. 

The cannon pinion drives the minute wheel, which, to- 
gether with its pinion, revolves loosely on a stud in the 



296 THE MODERN CLOCK. 

clock plate, or on an arbor between the frames. The mesh- 
ing of the minute wheel and cannon pinion should be as 
deep as is consistent with perfect freedom, as should also 
that of the hour wheel and minute pinion in order to prevent 
the hour hand from having too much shake, as the minute 
wheel and pinion are loose on the stud and the hour wheel 
is loose on the cannon, so that a shallow depthing here will 
give considerable back lash, which is especially noticeable 
when winding. 

The hour wheel has a short pipe and runs loosely on the 
cannon pinion in ordinary clocks. In quarter strike cuckoos 
a different train is employed and the wheels for the hands 
are both on a long stud in the plate and both have pipes; 
the minute wheel has 32 teeth and carries four pins on its 
under side to let off the quarters. The hour wheel has 64 
teeth and works close to the minute wheel, its pipe sur- 
rounding the minute wheel pipe, and held in position by a 
screw and nut on the minute pipe. A wheel of 48 and a 
pinion of 8 teeth are mounted on the sprocket arbor with a 
center spring for a friction, the wheel of 48 meshing with 
the minute wheel of 32 and the 8-leaf pinion with the hour 
wheel of 64. It will be recollected that the sprocket wheel 
takes the place of the barrel in this clock and there is no 
center arbor as it is commonly understood. The sprocket 
arbor in this case turns once in an hour and a half, hence it 
requires 48 teeth to drive the minute wheel of ^^ once in 
an hour, as it turns one-third of a revolution (or 16 teeth) 
every half hour. The sprocket arbor, turning once in an 
hour and a half, makes eight revolutions in twelve hours and 
its pinion of eight leaves working in the hour wheel of 64 
teeth turns the hour hand once in twelve hours. 

In ordinary rack and snail striking work the snail is gen- 
erally mounted on the pipe of the hour wheel, so that it will 
always agree with the position of the hour hand and the 
striking will thus be in harmony with the position of the 
hands. 



THE MODERN CLOCK. 297 

Striking Trains. — It is only natural, after finding cer- 
tain fixed relations in the calculations of time trains and 
motion work, that we should look for a similar point in 
striking trains, well assured that we shall find it here also. 
It is evident that the clock must strike the sum of the num- 
bers 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, II, 12, or 78 blows of the 
hammer, in striking from noon to midnight; this will be 
repeated from midnight to noon, making 156 blows in 24 
hours, and if it is a 30-hour clock, six hours more must be 
added; blows for these will be 21 more, making a total of 
177 blows of the hammier for a 30-hour strike train. The 
hammer is raised by pins set in the edge of a wheel, called 
the pin wheel, and as one pin must pass the hammer tail 
for every blow, it is evident that the number of pins in this 
wheel will govern the number of revolutions it must, make 
for 177 blows, so that here is the base or starting point in 
our striking train. If there are 13 pins in the pin wheel, 
it must revolve 13.5 times for 177 blows ; if there are 8 pins, 
then the wheel must revolve 22.125 times in giving 177 
blows; consequently the pinions and wheels back to the 
spring or barrel must be arranged to give the proper num- 
ber of revolutions of the pin wheel with a reasonable num- 
ber of turns of the spring or weight cord, and it is gen- 
erally desirable to give the same, or nearly the same, num- 
ber of turns to both time and striking barrels. 

If it is an eight-day clock the calculation is a little differ- 
ent. There are 156 blows every 24 hours; then as the ma- 
jority of "eight-day" clocks are realiy calculated to keep 
time for seven and a half days, although they will run 
eight, we have : 156 X 7-5 = 1,070 blows in 7.5 days. With 
13 pins we have 1,070 -f- 13 = 80 and 4-i3ths revolutions 
in the 7.5 days. If now we put an 8-leaf pinion on the pin 
wheel arbor and 84 teeth in the great wheel or barrel, we 
will get 10.5 turns of the pin wheel for every turn of the 
spring or barrel ; consequently eight turns of the spring will 



298 THE MODERN CLOCK. 

be enough to run the clock for the required time, as such 
clocks are wound every seventh day. 

Figuring forward from the pin wheel, we find that we 
shall have to lock our striking train after a stated number 
of blows of the hammer -each hour; these periods increase 
by regular steps of one blow every hour, so that we must 
have our locking mechanism in position to act after the 
passage of each pin, whether it is then used or not ; so the 
pinion that meshes with the pin wheel, and carries the lock- 
ing plate or pin on its arbor must make one revolution every 
time it passes a pin. If this is a 6-leaf pinion, the pins on 
the pin wheel must therefore be 6 teeth apart; or an 8-leaf 
pinion must have the pins 8 teeth apart; and vice versa. 
For greater convenience in registering, the pins are set in 
a radial line with the spaces of the teeth in the pin wheel, 
as this allows us to measure from the center of the pinion 
leaf. 

It will thus be seen that the calculation of an hour striking 
train is a simple matter; but if half hours are also to be 
struck from the train, it will change these calculations. 
For a 30-hour train 24 must be added to the 156 blows for 
24 hours, 180 blows being required to strike hours and half 
hours for 24 hours. These blows may be provided for by 
more turns of the spring, or different numbers of the wheels 
and pinions, which would then also vary the spacing of the 
pins. 

Half hours may also be struck directly from the center 
arbor, by putting an extra hammer tail on the hammer 
arbor, further back, where it will not interfere with the 
hammer tail for the pin wheel, and putting a cam on the 
center arbor to operate this second hammer tail. This 
simplifies the train, as it enables the use of a shorter spring 
or smaller wheels while providing a cheap and certain 
means of striking the half hours. Half-hour trains are 
frequently provided with a separate bell of different tone for 
the half hours, as with only one bell the clock strikes one 



THE MODERN CLOCK. 



299 




Fig. 92. Eight Day Hour and Half Hour Strike. 



300 THE MODERN CLOCK. 

blow at 12 .-30, I and 1 130, making the time a matter of 
doubt to one who Hstens without looking, as frequently 
happens in the night. 

Fig. 92 shows an eight-day, Seth Thomas movement, 
which strikes the hours on a count wheel train and the half 
hours from the center arbor. All the wheels, pinions, ar- 
bors, pins, levers and hooks are correctly shown in proper 
position, but the front plate has been left off for greater 
clearness. The reader will therefore be required to remem- 
ber that the escape wheel, pallets, crutch, pendulum and the 
stud for the pendulum suspension are really fixed to the 
front plate, while in the drawing they have no visible 
means of support, because the plate is left off. 

The time train occupies the right-hand side of the move- 
ment and the striking train the left-hand. Running up the 
right hand from the spring to the escape wheel, we find an 
extra wheel and pinion which is provided to secure the 
eight days' run. We also see that what would ordinarily 
be the center arbor is up in the right corner and does not 
carry the hands; further, the train is bent over at a right 
angle, in order to save space and get the escape wheel in 
the center at the top of the movement. The striking train 
is also crowded down out of a straight line, the locking 
cam being to the right of the pin wheel and the warning 
wheel and fly as close to the center as possible. This leaves 
some space between the pin wheel and the intermediate 
wheel of the time train and here we find our center arbor, 
driven from the intermediate wheel by an extra pinion on 
the minute wheel arbor, the minute wheel meshing with 
the cannon pinion on the center arbor. This rearranging 
of trains to save space is frequently done and often shows 
considerable ingenuity and skill ; it also will many times 
serve to identify the maker of a movement when its origin 
is a matter of doubt and we need some material, so that 
the planting of trains is not only a matter of interest, but 



THE MODERN CLOCK. 3OI 

should be studied, as familiarity with the methods of vari- 
ous factories is frequently of service to the watchmaker. 

Fig. 93 is the upper portion of the same striking train, 
drawn to a larger scale for the sake of clearness. It also 
shows the center arbor, both hammer tails and the stop on 
the hammer arbor, which strikes against the bottom of the 
front plate to prevent the hammer spring from throwing the 
hammer out of reach of the pins. The pin wheel, R, and 
count wheel, E, are mounted close together and are about 
the same size, so that they are shown broken away for a 
part of their circumferences for greater clearness in ex- 
plaining the action of the locking hook, 'C, and the locking 
cam, D. 

Fig. 94 shows the same - parts in the striking position, 
being shown as just about to strike the last blow of 12. 
Similar parts have similar letters in both figures. 

The count wheel, E, is loose on a stud in the Dlatc, con- 
centric with the arbor of the pin wheel, R. The pivot of R 
runs through this stud. The sole office of the count wheel 
is to regulate the distance to which the locking hook C, is 
allowed to fall. The count hook, A, and the locking hook, 
C, are mounted on the same arbor, B, so that they move in 
unison. If A is allowed to fall into a deep slot of the count 
wheel, C will fall far enough to engage the locking face of 
the cam D and stop the train, as in Fig. 93. If, on the 
contrary, A drops on the rim of the wheel, C will be held 
out of the locking position as D comes around (see Fig. 
94), and the train will keep on running. It will be seen 
that after passing the locking notch, D, Fig. 94, will in its 
turn raise the hook C, which will ride on the edge of D, 
and hold A clear of the count wheel until the locking notch 
of D is again reached, when a deep notch in the wheel will 
allow C to catch, as in Fig. 93, unless C is stopped by A 
falHng on the rim of the wheel, as in Fig. 94. 

One leaf, F, of the pinion of the locking arbor sticks out 
far enough to engage with the count wheel teeth and rotate 



302 



THE MODERN CLOCK. 




Fig. 93. Upper Portion of Striking Train Locked. 



THE MODERN CLOCK. 



303 




Fig. 94. Striking Train Unlocked and Running. 



3^4 



illK IvIODEIlN CJ.OCK. 



the wheel one tooth for each revolution of D, so that F 
forms a one-leaf pmion similar to that of a rack striking' 
train. Here we have our counting mechanism ; F and D 
go around together ; F moves E one tooth every revolution. 
A holds C out of action (Fig. 94) until A reaches a deep 
slot, when C stops the train by engaging D (Fig. 93). 

The count wheel, E, must have friction enough on its 
stud so that it will stay where the pin F leaves it, -when F 
goes out of action and thus it will be in the right "position ta 
suitably engage F on the next revolution. Too much fric- 
tion of the count wheel on its stud will use too much power 
for F to move it and thus slow the train; if there is too little 
friction here the count wheel may get in such a position 
that F will get stalled on the top of a tooth and stop the 
train. 

The count hook, A, must strike exactly in the middle of 
the deep slots, without touching the sides of the slots in 
entering or leaving, as to do this would shift the position of 
the count wheel if the rubbing were sufficient, or it might 
prevent A from falling (as A and C are both very light) 
and the clock would go on striking. If the hook A does not 
strike the middle of the spaces between the teeth of the 
count wheel, it will gradually encroach on a tooth and push 
the wheel forward or back, thus disarranging the count. 
Many a clock has struck 13 for 12 in this way because the 
hook was a little out. This did not occur in the smaller 
numbers because the action w^as not continued long enough 
to allow the hook to reach a tooth. The pin, F, should also 
mesh fairly and freely in the teeth of the count wheel, or 
a similar defect is likely to occur. 

When repairing or making new count hooks, A, Figs. 
93 and 94, ihey must be of such a length that they will enter 
the slots on a line radial with the center of the wheel. The 
proper length and direction are shown at A, Fig. 95, while 
B and C are wrong. With hooks like either B or C you 
can set or bend the hook to strike right at one and as you 



IIE MOl^EKN CLOCK. 



305 



turn the clock ahead the hook does not fall in far enough 
and at twelve it only strikes eleven. Then if you bend the 
same hook to strike right at twelve it will strike two at one 
and as you turn the clock ahead it will strike right at about 
five or seven. A, Fig. 95, being of the proper length and shape 
will give no trouble. ■ Many of-the count wheels of the older 
clocks w^ere divided by hand and are not as accurate as 
they should be ; when a wheel of this kind is found and a 
new'- w^heel cannot be substituted (because the clock is an 




Fig. 95, The proper length of the count hook. 



antique and must have the original parts preserved) it will 
sometimes require nice management of the hook A to obtain 
correc striking. A little manipulation of the pinion, F, 
Fig 93 is sometimes desirable also, if the count wheel is 
very bad. 

. The locking face of the cam, D, must also be on a line 
radial to its center, or it will either unlock too easily and 
go off on the slightest jar or movement of the clock, or the 
face will have too much draw and the hook C will not be 
unlocked when the clock is fully wound, and the spring 
pressure is greatest. In this case the clock will not strike 
when fully wound, but will do so when partly run down, 



306 THE MODERN CLOCK. 

and as the count wheel train strikes in rotation, without re- 
gard to the position of the hands, you will have irregular 
striking of a most puzzling sort. Repairs to this notch are 
sometimes required, when the corner has become rounded, 
and the best way to make them is to cut a new face on the 
cam with a sharp graver, being careful to keep the face 
radial with its center. 

Because the count wheel strikes the hours in rotation, 
regardless of the position of the hands, if the hands are 
turned backwards past the figure 12 on the dial the striking 
will be thrown out of harmony with the hands. To remedy 
this the count hook. A, has an eye on its rear end and a 
wire, shown in Fig. 92, hangs down to where it can be 
reached with the hand when the dial is on. Pulling this 
wire will lift A and C and cause the clock to strike ; by this 
means the clock may be struck around until the position of 
the striking train agrees with that of the hands. Where 
this wire is not present the striking is corrected by turning 
the hands back and forth between IX and XII until the 
proper hour is struck. 

Now we come to the releasing mechanism, which causes 
the clock to strike at stated times. I, Figs. 93 and 94, is an 
arbor pivoted between the plates and carrying three levers, 
H, K and J, in different positions on the arbor. H is directly 
under the count hook, A, and lifts A and C whenever J is 
pushed far enough to one side by L on the center arbor, 
which revolves once an hour. Thus L, through J, H and 
A, C, unlocks the train once every hour. When C is thus 
lifted the train runs until the warning pin, O, Figs. 93 and 
94, strikes against the lever K, which is on the same arbor 
with H and J. This preliminary run of the train makes a 
little noise and is called "warning," as the noise notifies 
us that the train is in position to commence striking. The 
lever K and the warning pin, O, then hold the train until 
L has been carried out of action with J and released it, when 



THE MODERN CLOCK. 307 

O will push K out of its path at every revolution and the 
clock will strike. 

The half hours are struck by L^ pressing the short ham- 
mer tail, G\ and thus raising and releasing the hammer once 
an hour. 

In setting up the striking train after cleaning, place the 
pin wheel so that the hammer tail, G, may be about one- 
fourth of the distance from the next pin, as shown in Fig. 
93 ; this allows the train to get well under way before meet- 
ing with any resistance and will insure its striking when 
nearly run down. If the hammer tail is too close to the pin, 
it might stop the train when there is but little power on. 

Then place D in the locked position, wath A in a deep 
slot of the count wheel and C in the notch of D. Next 
place the warning wheel with its pin, O, on the opposite side 
of its arbor from the lever K, see Fig. 93. This is* done to 
make sure that when it is unlocked for "warning" the train 
will run far enough to get the corner of the lock, D, safely 
past C, so that it will not allow C to fall into the notch again 
and lock the train when J, K and H are released by L. This 
is the rule followed in assembling these clocks at the fac- 
tories and is simple, correct and easily understood. A study 
of these points in Fig. 93. will enable any one to set up a 
train correctly before putting the front plate on. 

If the workman gets a clock that has been butchered by 
some one who did not understand it (and there are many 
such), he may find that when correctly set up the clock 
does not strike on the 60th minute of the hour ; in such a 
case a little bending of J, in or out as the case may be, will 
usually remedy the trouble. The same thing may have to 
be done to the hammer tails, G and G^, or the stop on the 
hammer arbor. If both hammer tails are out of position, 
bend the stop; if one is right, let the stop alone and bend 
the other tail. 

A rough, set or gummy spring will cause irregular stri- 
king. In such a case the clock will strike part of the blows 



308 THE MODERN CLOCK. 

and then stop and finally go on again and complete the 
number. Much time has been lost in examining the teeth 
of wheels and pinions in such cases when the trouble lay 
in the spring. Too strong a spring will make the move- 
ment strike too fast; too weak a spring will make it strike 
slow, especially in the latter part of the day or week, when 
it has nearly run down. 

Too small a fan, or a fan that is loose on its arbor, will 
allow the clock to strike too fast. If this fan is badly out 
of balance it will prevent the train from starting when 
there is but little power on. 

There is a class of clocks which have the count wheel 
tight on the arbor, outside the clock plate. Many of them 
are on much tighter than they should be. In such a case 
take an alcohol lamp and heat the wheel evenly, especially 
around the hub; the brass will expand twice as much as 
the steel and the wheel may then be driven off without 
injury. 

Fig. 96 shows another typical American eight-day train, 
made by the Gilbert Clock Company, and striking the half 
hours from the train. Here we notice, on comparing with 
Fig. 92, that there are many points of difference. First 
the notches on the count wheel, are twice as wide as they 
are in Fig. 92. This means that half hours are struck on 
the train; this will be explained later. Next there are two 
complete sets of notches on the wheel, which shows that 
the wheel turns only once in twenty-four hours, whereas 
the other makes two revolutions in that time. There are 
no teeth on the count wheel, so that it must be fast to its 
arbor, which is that of the great wheel and spring, while 
Fig. 92 has a separate stud and it is loose. The wheel being 
on the spring arbor and going once in 24 hours, there must 
be one turn of spring for each 24 hours which the train 
runs. There is no pin wheel in Fig. 96, but instead of this 
two pins are cut out of the locking cam to raise the hammer 
tail as they pass. There are also two locking notches in 



THE MODERN CLOCK. 



309 




Fig. 96. Half hours struck on the train. 



3IO THE MODERN CLOCK. 

the locking cam. The cams on the center arbor are stamped 
out of brass sheet, while those of Fig. 92 were of wire. 

Turning to the enlarged view in Fig. 97 and comparing 
it' with Fig. 93, we find further differences. The levers 
K and J are here made of one piece of brass, while the 
others were separate and of wire. The lifting lever, H, is 
flattened at its outer end in Fig. 93, while in Fig. 97 it is 
bent at right angles and passed under the count hook, A. 
The hook, C, Fig. 97, is added to the arbor, B, as a safety 
device, in case the locking hook should fail to enter its slot 
in the cam, D. It is shown as having just stopped the warn- 
ing pin in Fig. 96. There is but one hammer tail, G, and 
the hammer stop acts against the stud for the hammer 
spring, instead of against the bottom of the front plate, as 
in Fig. 92. 

The first important difference here is in the position of 
the count hook, A. In Figs. 92 and 93 the hook must be 
exactly in the middle of the slot, or there will be trouble. 
In trains striking half hours from the train, we must never 
allow the hook to occupy the middle of the slot, or we will 
have more trouble than we ever dreamed of. In this in- 
stance the count hook must enter the slot close to (but not 
touching) the side of the slot when the clock stops striking; 
then when the half hour is struck the count wheel will 
move a little and the hook must drop back into the same 
slot without touching; this brings it close to the opposite 
side of the same slot and the next movement will land the 
hook safely on top of the wheel for the strokes of the hour. 
Fig. 96 shows its position after striking the half hour and 
ready to strike the hour of two. Fig. 97 shows it dropping 
back after striking two. 

In setting up this train, see that the count hook, A, goes 
into the slot of the count wheel close to, but not touching, 
one side of the slot in the count wheel, and, after placing 
the intermediate, insert the locking cam, D, so that it en- 
gages the locking hook; then put in the warning wheel 



THE MODERN CLOCK. 



31^ 




Fig. 97 . Half hour strike on the count wheel. 



312 THE :modern clock. 

with the warning pin, O, safely to the left of the hook C, 
Fig. 97, so that it cannot get past that hook after striking. 
Placing the wheel with its warning pin six or eight teeth 
to' the left of the edge of the bottom plate is generally about 
right. The action of the levers, H, J, K, the hammer tail, 
G, and the cam, L, in striking the hours is the same as that 
already described in detail for Figs. 93 and 94, hence need 
not be repeated here. L^ strikes the half hours by being 
enough shorter than L to raise the hooks for one revolution, 
but not quite so high as for the hours. The cams L, L^ are 
friction tight on the center arbor and may be shifted on the 
arbor to register the striking on the 60th minute, if desired. 
When the hands and strike do not agree, turn the minute 
hand back and forward between IX and XII, thus striking 
the clock around until it agrees with the hands. 

Sometimes, if the warning pin is not far enough away, 
an eight-day clock will strike all right for a number of days 
and then commence to gain or lose on the striking side. It 
either does not strike at some hours, or half hours, or it 
may strike sometimes both hour and half hour before stop- 
ping. Take the movement out of the case and put the hands 
on; then move the minute hand around slowly until the 
clock warns. Look carefully and be sure there is no dan- 
ger of the clock striking when it warns. If this looks secure, 
then move the hand to the hour, making it strike; say it is 
going to strike 9 o'clock; when it has struck eight times, 
stop the train with your finger and let the wheels run very 
slow while striking the last one, and when the rod drops 
into the last notch stop the train again and hold it there. 

For the striking part to be correct, the warning pin on 
the wheel wants to be about one-fourth of a revolution 
away from the rod when the clock has struck the last timxC, 
or as soon as this rod falls down far enough to catch the 
pin. The object of this is so there is no chance of the 
warning pin getting past the rod at the last stroke; this it 
is liable to do if the pin is too close to the rod when the 



THE MODERN CLOCK. 313 

rod drops. If you will examine the clock as above, not only 
when it strikes IX, but all the hours from I to XII, you will 
generally find the fault. Of course, if the pin is too close 
to the rod when the rod drops, you must lift the plates apart 
and change the wheel so that the warning pin and the rod 
will be as explained. 

Ship's Bell Striking Work. — Of all the count wheel 
striking work which comes to the watchmaker, the ship's 
bell is most apt to give him trouble. This generally arises 
from ignorance as to what the system of bells on shipboard 
consists of and how they should be struck. If he goes to 
some nautical friend, he hears of long and short ''watches" 
or "full watches" and "dog watches." If he insists on de- 
tails, he gets the information that a "watch" is not a horo- 
logical mechanism, but a period of duty for a part of the 
crew. Then he is told of the "morning watch," "first dog 
w^atch," "afternoon watch," "second dog watch," "off 
watch," "on watch," etc. Now the ship's bell clock does 
not agree with these "watches" and was never intended to 
do so. As a matter of fact, it is simply a clock striking 
half hours from one to eight and then repeating through 
the twenty-four hours. 

The striking is peculiarly timed and is an imitation of 
the method in which the hours are struck on the bell of 
the ship. As this bell is also used for other purposes, such 
as tolling in fogs, fire alarms, church services, etc., it will 
readily be seen that a different method of striking for each 
purpose is desirable to avoid misunderstanding of signals. 

The method of striking for time is to give the blows in 
couples, with a short interval between the strokes of the 
couples and three times that interval between the couples. 
Odd strokes are treated as a portion of the next couple and 
separated accordingly, thus: 



314 THE MODERN CLOCK. 




Fig. 98. Ships bell clock. 



THE MODERN CLOCK. 315 

12:30 p. m. One Bell, O 

I :oo p. m. Two Bells, O O 

I :30 p. m. Three Bells, O O 

2:00 p. m. Four Bells, O O 

2:30 p. m. Five Bells, O O 

3 :oo p. m. Six Bells, O O 

3 :30 p. m. Seven Bells, O O 

4:00 p. m. Eight Bells, O O 

After striking eight bells the clock repeats, although the 
ship's bell is generally struck in accordance with the two 
dog watches (which are of two hours' duration each) be- 
fore commencing the evening watch (8 to 12 p. m.). It 
will thus be seen that the clock should strike eight at 12 m., 
4 p. m., 8 p. m., 12 p. m., 4 a. m,, and 8 a. m. 

In order to strike the blows in pairs two hammers are 
necessary, see Fig. 98; these hammers are placed close to- 
gether, but not in the same plane. The pin wheel has twenty 




















































t, ,T T I 1, I T »',T I 1, I f'.T T, i;T-I T T 



I' r' 'I ■ I • 'I LxJ "LlJI 



Fig. 100. The pins on the count wheel of the ships bell clock. 

pins, see Figs. 98, 99, 100; some of these pins are shorter 
than the others, so that they do not operate one of the ham- 
mer tails. These are shown graphically in Fig. 100 ; where 
the two oblong marks at figure i represent the tops of the 
hammer tails shown in Fig. 99. It will be seen by studying 
Fig. 100 that with the wheel moving from left to right, the 
inside hammer tail will be operated for one blow, while the 



3i6 



THE MODERN CI.OCK, 




Fig. 99. Enlarged view of striking work, ships bell clock. 



TlIK MODERN CLOCK. 317 

outer hammer tail will not De operated at all, thus giving 
but one blow, or "bell." At the next movement of the pin 
wheel, the outside hammer will be operated by the long pin 
and the inside hammer by the short pin, thus giving one 
blow of each hammer, or "two bells." 

We now have these hammer tails advanced along the 
wheel so that the outside one is opposite the figure 3 in the 
drawing, while the other is opposite the figure 2, with one 
pin between them. The next movement of the pin wheel 
advances them so that the outside hammer will pass the 
next short pin and consequently that hammer will miss one 
blow and the pair will therefore strike three — one by the 
outside hammer and two by the inside. It thus goes on 
until the cycle is completed, eight blows being struck with 
the last four pins. The striking in pairs is effected by 
having the two hammer tails close together, so that the 
pins will operate both hammer tails quickly and there will 
then be an interval of time while the wheel brings forward 
the next pins. This is so spaced that the interval between 
pairs is three times that between the blows of a pair and 
the hammer tails should not be bent out of this position, or 
if found so they should immediately be restored to it. Toll- 
ing the bells, instead of striking them properly, is very bad 
form at sea and generally leads to punishment if persisted 
in, so that the jeweler will readily perceive that his marine 
customers are very particular on this point, and he should 
go any length to obtain the proper intervals in striking. 

The pin wheel moves forward one pin for each couple 
of blows or parts of a couple, the odd blows being secured 
by the failure of the blow w^hen the hammer tail passes the 
short pin. Thus it moves as far for one bell as for two 
bells; as far for three bells as for four, etc. The result is 
that the count wheel has no odd numbers on it, but instead 
two 2's, two 4's, two 6's and tw^o 8's ; the first two are 
counted on the count wheel, but only one is struck on the 
pin wheel, owing to the short pin ; this is repeated at three, 



3l8 THE MODERN CLOCK. 

five and seven, when four, six and eight are counted on 
the wheel, but the last blow fails of delivery, owing to the 
short pin in the pin wheel at these positions. 

The center arbor carries two pins, L and L^, to unlock 
the train through the lever J, as it is really a half-hour- 
striking clock. The count hook, A ; locking hook, C ; count 
wheel, E; pins, P, and other parts have similar letters for 
similar parts as in the preceding figures and need not be 
further explained, as the mechanism is otherwise similar 
to the Seth Thomas movement shown in Fig. 92. 



CHAPTER XVIL 

CLEANING AND REPAIRING CUCKOO CLOCKS. 

The cuckoos are in a class by themselves for several rea- 
sons, all of which have to do with their construction and 
should therefore be understood by the watchmaker. They 
are bought as timepieces by but two classes of people : those 
who were used to them in their former homes in Europe 
and buy them for sentimental reasons; and those who ad- 
mire fine wood carvings as works of art and desire to pos- 
sess a finely carved cuckoo clock for the reasons which 
govern in the purchase of paintings and statuary, bronzes, 
and other art objects. For this reason cuckoos have never 
been a success when attempts have been made to cheapen 
their production by the use of imitations of wood carving in 
composition or metal. The use of cuckoos in plain cases, 
with springs instead of weights, has also been attempted 
with the idea of thereby securing an inclosed movement, 
as in ordinary clocks; but while it offers advantages in 
cleanliness and protection of the movement, such clocks have 
never become popular, as they have lost their character as 
works of art by being enclosed in plain cases, or have be- 
come rather erratic in rate by the substitution of springs 
for weights. 

The use of exposed weights and pendulum necessitates 
openings in the bottom of the case through which the dust 
enters freely and this makes necessary unusual side shake, 
end shake and freedom of depthing of the wheels and pin- 
ions and also the use of lantern pinions and an amount of 
driving weight in excess of that necessary for protected 
movements, as there must be enough weight to pull the 

319 



320 THE MODERN CLOCK. 

cuckoo movement through obstructions which would stop 
the ordinary movement. 

Repairers therefore should not attempt to close worn 
holes as snugly as in the ordinary movements, as when this 
is done the clock generally stops about three weeks after it 
has left the shop and a "comeback" is the result. Lighten- 
ing the driving weights will have the same result, as the 
movement must have sufficient power to pull it through 
when dirty. As the plates and wheels are generally of cast 
metal, cutting of pivots from running dry is frequent in 
old clocks, and where it is necessary to close the holes care 
must be taken not to overdo it. 

Another point where repairers fail is in not polishing the 
pivots. Many watchmakers seem to think that any kind 
of a pivot will do for a clock, although they take great care 
of them in their watchwork. Rough and dry pivots will 
cut the holes in a clock plate deep enough to wedge the 
pivots in the holes like a stuck reamer and stop a clock 
just after it has been repaired, when if they had been prop- 
erly polished the job would not have come back. 

The high prices of wood carving in America and the 
necessity for its genuineness, as explained above, has re- 
sulted in making it necessary to spend as little as possible 
for the movements ; hence we ordinarily find a total lack of 
finish on the movements, and this, with the great freedom 
everywhere evident in its construction and the apparent 
excess of angular motion of the levers, combine to give it 
an appearance of roughness which surprises those who see 
them but rarely. 

It has been frequently suggested by watchmakers that if 
the cases only were imported and the movements were made 
by the American factories better results should be obtained, 
in appearance at least. They forget that the bellows, pipes 
and birds, with their wires, are parts of the movements 
and the cost of having these portions made in this country 
is prohibitive, so that the whole movement is imported. 



THE MODEIiN CLOCK. 32 1 

Arrangements are now being made by at least one firm to 
have the frames and wheels made of sheet metal by auto- 
matic machinery, instead of being cast and finished in the 
usual way, and when this is done the appearance of the 
movements will be greatly improved, so that American 
watchmakers will regard them with a more kindly eye. 
So far as is known to the writer all cuckoo movements are 
im.ported, although one firm is doing a large and constantly 
growing trade in such clocks with cases made in America. 

There are a number of importing firms who sell to job- 
bers, large retailers and clock companies only, and as the 
large American clock manufacturers all list and carry 
cuckoos the clocks find their way to the consumer through 
many and devious channels. Probably more are sold in 
other ways than through the retailers for the reason that 
the average retailer does not understand the cuckoos and 
is reluctant to stock them, thereby deliberately avoiding a 
large amount of business from which he might make a 
haiidsome profit. 

Under the general term Cuckoos are listed several kinds 
of movements, all having bellows, pipes and moving fig- 
ures, such as the cuckoo, cuckoo and quail, trumpeter, etc., 
with or without the regular hammers and gongs of the ordi- 
nary movements. 

Figs. TOi and 102 show front and back views of a tmie 
train in the center with quail strike train on the left and 
cuckoo strike train at the right. The positions of arbors, 
levers, depthings of trains, etc., are exact, but the m.ove- 
ment plates have been left off for greater clearness, so that 
the arbors appear to be without support. The positions of 
the pillars are shown by the shaded circles above and below 
the trains in Fig. loi. The parts have the same letters in 
both Figs. ]Ci and 102, althoigh as the movement is turned 
around to show the rear in 102, the quail train appears on 
the right side. 



322 



THE MODERN CLOCK. 




Fig. 101. Front View of Quail and Cuckoo Strike Movement. 



THE MODEJiX CLOCK. 



NAMES OF PARTS. 



3- 



A— Quail count wheel. O— Quail Lifting pin wheel. 

B— Quail striking cam. P— Cuckoo lifting lever. 

C— r^liuute wheel. Q— Cuckoo warning lever. 

D— Quail lifting lever. R— Cuckoo lifting pin. 

E— Quail count hook. S— Cuckoo locking arm. 

F— Quail locking arm. T— Cuckoo count hook. 

G— Quail bird stick; U— Cuckoo striking cam. 

alpo called bird holder. V— Cuckoo lifting pin wheel. 

H— Quail bellows arm. W— Cuckoo count wlieel. 
I— Quail bellows lifting lever. X— Cuckoo bellows lifting lever. 

J— Quail gong hammer. Y — Cuckoo hnnimcr. 

K— Quail warning lever. Z— Cuckoo biid stick; 
L,— Quail lifting pin. also called bird holder. 

M— Quail bird stick lever. S^— Cuckoo bird stick lever. 
iS — Quail hammer lever. 

In examining a movement the student discovers a peculi- 
arity of cuckoo frames, which is that the pivot holes for 
several of the arbors of the striking levers have slots filed 
into them, reaching to the edges of the frames and nar- 
rower than the full diameter of the pivot holes. This is 
because such arbors have levers riveted into them which 
must function in front, between and at the rear of the plates 
and in setting up the movem.ent the. slots are necessary to 
allow^ the end levers to pass through the holes. Such arbors 
as have slots on the front plates are inserted and placed in 
their proper positions before setting the train wheels wdth 
which they function. The others are first inserted in the 
back plate and turned to position while putting on that 
plate. 

Both quail and cuckoo trains are set up very simply and 
surely by observing the following points : In the quail 
train, when the quail bellows lever, H, is just released from 
a pin in the pin wdieel, O, the locking lever, F, must just 
fall into the slot of the locking cam, B; the warning pin 
should then be near the fly pinion and the count hook, K, 
drop freely into the count wheel, A. 

On the cuckoo side we find two levers, X ; the upper one 
of these operates the low note of the cuckoo call and the 
lower one the high note. When this upper lever is released 



324 



THE MODERN CLOCK. 




Fig. 102. Rear View of Quail and Cuckoo Movement. 



THE MODERN CLOCK. 



3-5 



from a pin in the pin wheel, the cuckoo locking lever, S. 
must drop into its locking cam, U, and the count hook, T, 
drop into its count wheel, while the warning pin must be 
near the fly pinion. After the run has stopped and the 
trains are fully locked the warning pins will be as shown 
in Fig. 102; but at the moment of locking they should be 
as described above. 

The operation is as follows: Turning to Fig. loi, we 
find the minute wheel, C. has four pins projecting from its 
rear surface. This revolves once per hour and conse- 
quently the pins raise the lifting lever, D, every fifteen 
minutes. Here is a point that frequently is productive of 
trouble. The reader will readily see that if the hands of 
a cuckoo are turned backv/ard the pins in the minute wheel 
w^ill bend this wire, D, and derange the striking, as the 
warning lever is also attached to the same arbor. Never 
push the hands baekzvard on a cuckoo clock ; ahvays push 
them forward. If the striking and hands do not register 
the same time, take off the weights of the striking trains ; 
then push the hands forward until they register the hour 
which the trains struck last. As there is no power on the 
trains they wdll not be operated, the only action being the 
rising and falling of the lever, D, as the pins pass. When 
the hands point to the hour last struck by the trains, put 
on the striking weights again and push the hands forzi'ard, 
allowing time for each striking, until the clock has been 
set to the correct time. 

Upon the lifting lever, D, being raised sufficiently the 
warning lever, E, on the same arbor is lifted into the path 
of the warning pin and at the same time unlocks the train 
by pressing against the lifting pin, L, in the locking lever, 
F. The locking lever, F, count hook, K, and the bird 
holder lever, M, are all on the same arbor and therefore 
work in unison. When D drops, E releases the warning 
pin and the train starts. The pin wdicel has pins on both 
sides, the rear pins operate the gong hammer, N, J ; the 



2--" TJIE ISIODERN CI.OCK. 

front pins operate the quail bellows, I, H. The rising, and 
falling of the unlocking lever, F, operates the bird holder, 
G, through M and the wire in the bellows top tilts the tail 
of the bird and flutters the wings. When the fourth quarter 
has been struck, the pins shown in the quail count wheel, 
A, operate the hour hfting lever, P, and the action of that 
train becomes similar to that of the quarter train just de- 
scribed, with the difference that there are two bellows 
levers, X, for the high and low notes of the cuckoo, whereas 
there is but one for the quail. 

There are several adjustments necessary to watch on 
these clocks. The wires to operate the bellows from the 
levers X and H may be so long that the bellows when 
stretched to its full capacity may not allow the tails of X 
and H to clear the pins of the pin wheels and thus stop 
the trains. The pins should clear safely w:th the bellows 
fully opened. The levers M and S', which operate .he 
bird holders, G and Z, may be turned in their arbors so as 
to be farther from or closer to the bird holder; this regu- 
lates the opening and closing of the doors and the appear- 
ance of the birds ; if there is too much movement the birds 
may be sent so far out that they will not return, but will 
stay out and stop the trains. Moving S' and M towards 
the bird holders, Z and G, will lessen the amount of this 
motion and the contrary movement will increase it. 

Another important source of trouble — because generally 
unsuspected — is the fly. The fly on a cuckoo train must 
be tight ; a loose fly will cause too rapid striking and allow 
tlic train to overrun, making wrong striking, or in a very 
bad. case it will not stop until run down. When this hap- 
pens turn your attention to the fly and make sure that it is 
tight before doing any bending of the levers, and also see 
to the position of the warning pin. 

Sometimes the front of the case (which is also the dial) 
will warp and cause pressure on the ends of the lever ar- 



THE MODERN CLOCK. 



3-7 



bors and thus interfere with their proper working. Be 
sure that the arbors are free at both ends. 

When replacing worn pins in the striking trains, care 
should be taken to get them the right length, as on account 
of the large amount of end shake in these movements they 
may slip past the levers w^ithout operation, if too short, or 
foul the other parts of the train if too long. For the same 
reasons bending the levers should only be done after ex- 
hausting the other sources of error and then be undertaken 
very slowly and cautiously. 

The notes of a cuckoo are A and F, jirst belov/ middle C ; 
these should be sounded clearly and with considerable vol- 
ume. If they are short and husky in tone it may be due 
to holes in the bellow^s, too short stroke of bellows, removal 
of the bellows weights, E, Fig. 103, dirt in the orifices of the 
pipes, or cracks in the pipes. Holes in the bellows, if small 
and not in the folds of the kid, may be m.ended by being 
glued up with paper or kid, or a piece of court plaster 
which is thin enough to not interfere wi'di the operation of 
the bellow^s. If much worn a new bellow^s should be sub- 
stituted. Cracks in the pipes may be mended with paper. 

The orifice of the pipe, if dirty, may be cleaned with a 
piece of mainspring filed very thin and smooth and care- 
fully inserted, as any widening or roughening of this slit 
w^ill interfere with the tone. Sometimes a clock comes in 
v;hich has been spoiled in this regard, then it beconies nee 
essary to remove the outer portion or lip. A, Fig. 1 03, of 
the slot (which is glued in position) and make a new inner 
lip, B, or file the old one smooth again. The proper shape 
is shown in B, Fig. 103, while C and D show improper 
shapes which interfere with the tone. 

]\Iuch time and money has been spent in trying to avoid 
the inherent defects of this portion of the clock; sometimes 
the lips will swell or warp and close the orifice; sometimes 
they wdll shrink and make it too wide ; in either case a loss 
of purity of tone is the result. Brass tubes, if thm enougn 



328 



THE MODERN CLOCK, 




Fir:. 193. Cuckoo bellows and pipe. A, outer lip; B, inner lip; C, D, 
incorrect forms of lip. 



THE MODERN CLOCK. 329 

to be cheap, give a brassy tone to the notes ; compositions 
of lead, tin and antimony (organ pipe metal) are readily 
cast, but give a softer, duller tone of less volume than the 
wood. Celluloid lips to a wooden tube were at first thought 
to be a great success, but were found to warp as they got 
older. Bone lips are costly ; so there is nothing at present 
that seems likely to displace well seasoned wood, where 
discriminating lovers of music and art demand purity and 
correctness of tone, reasonably accurate time, artistic sculp- 
tural effects and durability, all in one article — a high class 
cuckoo clock. 

When sending a clock home after repairing, each of the 
chains should be tied together with strings just outside the 
bottom of the case so that they will not slip off the sprockets 
and the customer should be instructed to hang the clock 
in its accustomed position before cutting the strings and 
attaching the weights. 



CHAPTER XVIII. 

SNAIL STRIKING WORK, ENGLISH, FRENCH AND AMERICAN. 

While the majority of snail striking movements made in 
America are on the French system, because they are cheaper 
when made in that way, still this system is so condensed 
and so difficult to illustrate, with all its mechanism packed 
in a small space between the plates, that the , student will 
gain a much better idea of the rack and snail and its prin- 
ciples by first making a study of an English snail striking 
clock, which has the whole of the counting and releasing 
levers placed outside the front plate, where they can occupy 
all the room that may be necessary. The calculation and 
planting of the striking train do not differ from those using 
the count wheel, up to and including the single toothed 
pinion or gathering pallet. The stopping of the train after 
striking is different and the counting is divided, being de- 
pendent upon four pieces acting in conjunction in an hour 
strike of the simplest order, which number may run to a 
dozen in a repeating clock. 

As the count wheel system had the defect of getting out 
of harmony with the hands when the latter are turned back- 
ward, so the snail system has its defects, which are the dis-. 
placement of the rack and failure to stop the striking in 
some clocks if the striking train runs down before the time 
side and is then rewound, and a most puzzling inaccuracy 
of counting, resulting from slight wear and inaccuracy of 
adjustment. We mention these things here because they 
have an influence on the construction of the clock and an 
advance knowledge of them will serve to make clearer some 
of the statements which follow. 

330 



THE MODERN CLOCK. 33I 

Hour and Half-Hour Snail Striking Work. — Fig. 
104 is a view of the front plate of an English fusee strik- 
ing clock, on the rack principle. The going train occupies 
the right and center and the striking train the left hand. 
The position of the trains is indicated in dotted lines, the 
trains having barrels and fusees as shown by the squared 
arbors, all the dotted work being between the clock plates, 
and that in full lines being placed on the outside of the 
front plate, under the dial. The connection between the 
going train and the striking w^ork is by means of the motion 
w^ieel on the center arbor, and connection is made between 
the striking train and the counting work by the gathering 
pallet, F, wdiich is fixed to the arbor of the last wheel but 
one of the striking train, and also by the warning piece, 
which is shown in black on the boss of the lifting piece, A. 
This w^arning piece goes through a slotted hole in the plate, 
and during the interval between warning and striking stands 
in the path of a warning pin in the last wheel of the striking 
train. The motion wheel on the center arbor, turning once 
in an hour, gears with the minute wheel, E, which has an 
equal number of teeth. There are tw^o pins opposite each 
other and equidistant from the center of the minute wheel, 
which in passing raise the lifting piece, A, every half hour. 
Except for a few minutes before the clock strikes, the strik- 
ing train is kept from running by the tail of the gathering 
pallet. F, resting on a pin in the rack, C. Just before the 
hour, as the boss of the lifting piece, A, lifts the rack hook 
B, the rack C, impelled by a spring in its tail, falls back 
until the pin in the lower arm of the rack is stopped by the 
snail, D. This occurs before the lifting piece, A, is released 
by the pin in the minute wheel, E, and in this position the 
warning piece stops the train. Exactly at the hour the pin 
in the minute wheel, E, gets past the lifting piece, A, wdiich 
then falls, and the train is free. For every blow struck by 
the hammer the gathering pallet, F, which is really a one- 
toothed pinion, gathers up one tooth of the rack, C, which 



332 THE MODERN CLOCK. 

is then held, tooth by tooth, by the point of the hook, B. 
After the pinion, F, has gathered up the last tooth, its tail is 
caught by the pin in the rack, which stops and locks the 
tram, and the striking ceases. 

The snail, O, is mounted on a twelve-toothed star wheel, 
placed on a stud in the plate, so that a pin in the motion 
wheel on the center arbor moves it one tooth for each revo- 
lution of the motion wheel, and it is then held in position by 
the click and spring as shown. The pin, in moving the star 
wheel, presses back the click, which not only keeps the 
star wheel steady, but also completes its forward motion 
after the pin has pushed the tooth past the projecting center 
of the click. The steps of the snail are arranged so that at 
one o'clock it permits only sufficient fall of the rack for one 
tooth to be gathered up, and at every succeeding hour gives 
the rack an additional motion equal to one extra tooth. It 
will be seen that where a star wheel is used a cord or wire 
attached to A and run outside the case, so that A may be 
lilted, will cause the clock to repeat the hour whenever 
desired. 

The lower arm of the rack, C, and the lower arm of the 
lifting piece. A, are made of brass, and thin, so as to yield 
when the hands of the clock are turned back ; the lower 
extremity of the lifting piece. A, is a little wider, and bent 
to a slight angle with the plane of the arm, so as not to butt 
as it comes into contact with the pin when this is being 
done. If the clock is not required to repeat, the snail may 
be placed upon the center arbor, instead of on a stud with 
a star wheel as shown, and this is generally done with the 
che::per class of hour striking clocks ; but the position of the 
snail is not then so definite, owing to the backlash of the 
motion wheels, so that it will not repeat correctly, as the 
pin of the rack m,ay fall on a slope of the snail and, besides, 
a smaller snail must be used, unless it is brought out to 
clear the nose of the minute wheel cock, or bridge if one 
be used. 



THE MODERN CLOCK. 



333 



..^^^P^^^^ 




Fig. 104. Hour and half hour snail striking work "with fusee train. 



334 



THE MODERN CLOCK. 



Half-Hour Striking. — The usual way of getting the 
clock to strike one at the half-hour, is by making the first 
tooth of the rack, C, lower than the rest, and placing the 
second pin in the minute wheel, E, a little nearer the center 
than the hour pin, so that the rack hook, B, is lifted free 
of the first tooth only at the half hour. But this adjustment 
is too delicate after some wear has occurred and the action 
is then liable to fail altogether or to strike the full hour, 
from the pin getting bent or from uneven wear of the parts. 
The arrangement shown in Fig. 104 is generally used in 
English work, as it is much safer. One arm of a bell crank 
lever rests on a cam fixed to the minute wheel, E. This 
arm is shaped so that just before the half-hour the other ex- 
tremity of the bell crank lever catches a pin placed in the 
rack, C, and permits it to release the train and fall the dis- 
tance of but one tooth. This is the position shown in Fig. 
104. After the half-hour has struck, the cam carries the 
hook free from the pin in C. 

Division of the Hour Snail.— The length of the rack 
tail, from the center of the stud hole in the rack to the 
center of the pin, should be equal to the distance between 
the center of the stud hole and the center of the snail. The 
difference between the radius of the top and the radius of 
the bottom step of the snail may be obtained by getting the 
angular distance of twelve teeth of the rack from center to 
pin. See A B, CD, E F, Fig. 105, which show the total 
distances for twelve steps of the snail for rack tails of 
different lengths. Divide the circumference of a piece of 
brass into twelve parts and draw radial lines as shown in 
Fig. 106. Each of these spaces is devoted to a step of the 
snail. Draw circles representing the top and bottom step. 
Divide the distance, A B or E F, Fig. 105, between these 
two circles, into eleven equal parts, and at each division 
draw a circle which will represent a step of the snail. The 
rise from one step to another should be sloped as shown, so 
as to raise the pin in the rack arm if the striking train has 



THE MODERN CLOCK. 



335 



been allowed to run down, and it should be resting on the 
snail when it is desired to turn the hands back. The rise 
from the bottom to the top step is bevelled off, so as to push 
the pin in the rack arm on one side, by springing the thin 
brass of the arm and allow it to ride over the snail if it is 
in the way when the clock is going. It should also be 
curved to avoid interference with the pin. Clockmakers 
making new snails when repairing generally mark off the 




Fig. 105. Rack, showing method of getting sizes of snail steps accord- 
ing to distance from the rack center to the pin in the rack tail. 



snail on the clock itself after the rest of the striking work 
is in position. A steel pointer is fixed in the hole of the 
lower rack arm, and the star wheel jumped forward twelve 
teeth (one at a time) by means of the pin in the motion 
wheel. After each jump a line is marked on the blank 
snail with the pointer in the rack arm by moving the rack 
arm. These twelve lines correspond to the twelve radial 
lines in Fig. io6. The motion wheel is then turned suffi- 
ciently to carry the pin in it free of the star wheel and 
leave the star wheel and blank snail quite free on their stud. 
The rack hook is placed in the first tooth of the rack, and 
v^hile the pointer in the rack arm is pressed on the blank 
snail, the latter is rotated a little, so that a curve is traced 
on it. The rack hook is then placed in the second, and after- 



336 THE MODERN CLOCK. 

wards in the succeeding teeth consecutively, and the opera- 
tion repeated till the twelve curves are marked. There is 
one advantage in marking off the snail in this way. Should 
there be any inaccuracy in the division of the teeth of the 
rack, the steps of the snail are thus varied to suit it. This 
frequently occurs in old clocks which have had new racks 
filed up by hand by some watchmaker. 

Reference to the drawing. Fig. 105, will show that the 
rack is laid out as a segment of a wheel with teeth occupy- 
ing two degrees each, with a few teeth added for safety. 
Fourteen to sixteen teeth are generally provided, for the 
following reasons : If the first tooth is used to strike the 
half hours, it may in time become worn so that it can no 
longer be stretched to its proper length. In such cases 
moving the pin two degrees nearer the rack teeth will allow 
us to use the teeth from the second to the thirteenth in 
striking twelve, which makes a cheap and easy repair, as 
compared to inserting a new tooth or making a new rack. 

Weight driven snail clocks should have the weight cords 
of the striking side long enough so that the striking train 
will not run down before the time train, as in such a case 
the rack tail is pushed to one side by the progress of the 
snail (which is carried on the time train and is still run- 
ning) ; then the rack will drop clear out of reach of the 
gathering pallet and when the striking train is wound that 
train will continue striking until it runs down, or the dial 
is removed and the rack replaced in mesh with the gather- 
ing pallet. This happens with short racks and with large, 
old-fashioned snails. By leaving a few more teeth in the 
rack the rack tail will strike the stud, or hour wheel sleeve, 
before the rack teeth get out of reach of the gathering 
pallet. 

Many watchmakers put a stud or pin in the plate to stop 
the rack from falling beyond the twelfth step, to prevent 
troubles of this kind. 



THE MODERN CLOCK. 



337 



The rack tail is friction-tight on its arbor and should be 
adjusted so that the proper tooth shall come in mesh with 
the gathering pallet for each step of the snail, or irregular 
striking will result. Such a clock may strike one, two, three 
and four correctly and then strike six for five, or seven or 
nine for eight, or thirteen for twelve, or it may strike one 
or two hours wrong and the rest correctly. This is be- 
cause the gathering pallet, F, Fig. 104, does not carry the 




rack teeth safely past the edge of the rack hook, B, owing 
to the tail of the rack not being properly adjusted. The 
teeth should all be carried safely past the edge of the hook 
and then be dropped back a little as the hook engages ; this 
is the more necessary to watch with hand-made racks and 
snails, or after putting in a new, and therefore larger, pin 
in the rack tail to replace one which is badly worn. 

The snail should be put on so that the pin in the rack 
tail will strike the center of each step, or there is danger of 
irregular striking, or of failure to strike twelve, owing to 
the pin striking the surface of the cam midway between 
one and twelve and thus preventing the rack from falling 



33^ THE MODERN CLOCK. 

the requisite number of teeth. When this occurs the clock 
will jam and stop. 

The rack hook, B, Fig. 104, should be lifted far enough 
so that the rack will fall clear of the hook without the teeth 
catching and making a rattling noise as they pass the hook. 
In many old hour strikes the first tooth of the rack is left 
longer than the rest to ensure this freedom of passage 
when the rack is released. 

The gathering pallet, F, is the weakest member of the 
system and will be very Hkely to be split or worn out in 
clocks brought in for repair. It should be squared on its 
arbor, or pinned, but many are not. If split, and the arbor is 
round, where the pallet is put on, it may cause irregular 
striking by opening on the arbor and permitting the train 
to run when the tail strikes the pin in the rack. A new one 
should be made so as to lift one tooth and a very little of 
the next one at each revolution. It is necessary to cause 
the gathering pallet to lift a little more than one tooth of the 
rack, and let it fall back again, to insure that one will always 
be lifted; because if such was not the case the clock would 
strike irregularly, and would also be liable sometimes to 
strike on continually till it ran down. If the striking part is 
locked by the tail of the gathering pallet catching on a pin 
in the rack, the tail should be of a shape that will best pre- 
vent the rack from falling back when the clock wcirns for 
striking the next hour ; and of course the acting faces of the 
pallet must be perfectly smooth and polished. 

The teeth of the rack may require dressing up in some 
cases and to allow this to be done the rack may be stretched 
a little at the stem, with a smooth-faced hamm.er, on a 
smooth anvil ; or, if it wants much stretching, take the 
pene of the hammer and strike on the back, with the -front 
lying on the smooth anvil. The point of the rack hook, B, 
will probably be much worn, and when dressing it up it 
will be safe to keep to the original shape or angle. The 
point of the rack hook is always broader than the rack, and 



THE MODERN CLOCK. 339 

the mark worn in it will be about the middle of the thick- 
ness ; so enough will be left to show what the original shape 
or angle was. 

After cleaning, particularly if it be French, look for dots 
on the rims of the wheels, and for pinions with one end 
of one leaf filed ofif slantingly. When putting it together, 
place the pin wheel (that is the one with the pins) and the 
pinion it engages with so that the leaf of the pinion (which 
you will find filed slanting at one extremity) enters be- 
tween the two teeth of the wheel, opposite which you will 
find a countersunk mark, on the side of the wheel. See also 
that the gathering pallet, F, w^hich lifts the rack, does so 
■at the same time that the gong hammer falls. Then place 
the hour and minute wheels and cannon pinion so that the 
countersunk marks on each line with each other. Neglect 
of the marks on a marked train generally means that you 
will have to take the clock down again and set it up prop- 
erly before it will run ; therefore pay attention to these 
marks the first time. 



Quarter Chiming Snail Strikes. — Fig. 107 shows the 
counting mechanism and trains of an English, fusee, quar- 
ter-strike work. The time train occupies the center, the 
hour striking train the left and the chiming train the right. 
All the train wheels are between the plates and are dotted 
in as in Fig. 104, while the counting mechanism is on the 
front plate, behind the dial and is drawn in full lines, to 
show that it is outside. 



GOING TRAIN. 

Fusee Wheel 96 

Pinion 8 

Center Wheel 84 

Pinion 7 

Tliird Wheel 78 

Pinion 7 



340 THE MODERN CLOCK. 

STRIKING TRAIN. 

Fusee Wheel 84 

Pinion 8 

Pin Wheel, 8 pins in Pin Wheel 64 

Pinion 8 

Pallet Wheel 70 

Pinion 7 

Warning Wheel 60 

Fly Pinion 7 

CHIMING TRAIN. 

Fusee Wheel 100 

Pinion 8 

Second Wheel 80 

Pinion 8 • 

Pallet Wheel ' 64 

Pinion 8 

Chiming Wheel 40 

Warning Wheel 50 

Fly Pinion 8 

The reader will see a marked resemblance between the 
hour and time trains of Fig. 104 and the same trains of 
Fig. 107. The hour rack hook in 107, however, is hung 
from the center and the hour warning lever is raised by a 
spring instead of a Hfting piece. 

The minute wheel of Fig. 107 carries a snail of four 
steps, corresponding to the four teeth of the quarter rack, 
and the tail of the quarter rack is bent upwards towards the 
rack, to engage with the quarter snail. The quarter rack 
carries a pin which projects on both sides of the rack; one 
side of this pin stops the tail of the quarter gathering pallet 
and therefore locks the train as fully described in Fig. 104. 
The other side of the same pin acts on the tail of the hour 
warning lever, so that whenever the quarter rack falls the 
hour warning lever is released and its spring moves it into 
the path of the hour warning pin. This goes on whether 
the hour rack hook is released or not. Behind the quarter 
snail, there are four pins in the minute wheel ; these pins 



THE MODERN CLOCK. 



341 




Fig. 107. Quarter chiming snail strike, Englisli fusee movement. 



342 



THE MODERN CLOCK. 



raise the quarter lifting piece, which raises the quarter 
rack hook and the quarter warning lever at the same time, 
thus warning and dropping the quarter rack; as soon as 
the lifting piece drops, the warning lever and rack hook 
are released and the quarter train starts. 




Fig. 108. Eight day snail half hour strike, French system, striking 
train locked. 



One, two, three, or four quarters are chimed according 
to the position of the quarter snail, wdiich turns with the 
minute wheel. At the time for striking the hour (when 
the quarter rack is allowed to fall its greatest distance), the 
pin in it falls against the bent arm of the hour rack hook, 
and releases the hour rack and hour w^arning lever. As the 
last tooth of the quarter rack is gathered up, the pin in the 
quarter rack pulls over the hour warning lever, and lets off 



THE MODERN CLOCK. 343 

the hour striking train. The position of the pieces in the 
drawing is as they would be directly after the hour was 
struck. 

Figs. 108, 109 and no arc three views of the New 
Haven eight-day snail strike, which is on the French sys- 
tem. As nearly all American strikes utilize this system and 
the work is between the plates, this may be considered a 
typical American snail strike. 

As will be seen in Fig. io8, by the two pins at the center 
arbor, immediately behind the snail, this is a half-hour 
strike ; and as the rack hook has for its lower step a little 
more than twice the depth of the other steps in the snail, it 
will readily be perceived that this rack hook may be 
pushed almost out and thus release the train without drop- 
ping the rack. This is the method pursued in striking half 
hours. 

Figs. 109 and no show the parts more clearly than in 
108. They are drawn a little larger than actual size and 
wc will discover that the rack is the only portion of this 
system that vrorks by gravity, all the others being spring 
operated. Wc sec here the pins J K, which are used to 
push out the lever M sufficiently far so that the upper 
portion, which is bent at right angles to form a stop, will 
free the warning pin O and allow the train to run. The 
rack hook and the locking lever L are mounted on the same 
arbor and are kept in position by a coiled spring on the 
arbor until they are pushed out by the lower projection 
at the upper end of M for either the half-hour or hour 
strike. 

As shown in Fig. 109, the lever M and the rack hook are 
pushed out by J far enough to pass the warning pin O and 
to unlock the train, which is normally locked by the pin N 
and the lever L. G is the gathering pallet, which is a long 
pin in a lantern pinion as in the ordinary count wheel strike. 
H is the hammer tail and P the pin wheel ; R is the rack and 
T the rack tail. The rack arm is curved to pass the center 



344 THE MODERN CLOCK, 

arbor when dropping for twelve and the rack tail is bent 
toward the teeth in order that it may admit of a longer rack 
in a small movement, thus permitting of a large snail 
and consequently less liability of disarrangement. The 
same necessity of the proper adjustment of the rack tail T 
with the snail exists as has already been spoken of in regard 
to the English form of the snail strike. 

In Fig. no will be seen the rack dropped clear with the 
tail resting clear of the snail at one stroke from the snail. 
In other words, the train is now in position to give eleven 
more strokes, having struck the first stroke of twelve. By 
comparison with Fig. 109, it will be seen that the spring 
actuated arm M has been thrown forward so that its doc: is 
resting on the center arbor, after having been released from 
the hour pin K. This holds M out of the way of the w^arn- 
ing pin O and the rack hook and allows the parts to oper- 
ate as fully described with the English rack. 

The gathering pallet G must have as many teeth as there 
are teeth between the pins in the pin wheel P. The train 
is locked by L coming in contact with X, the locking pin 
on the wheel on the same arbor as the gathering pallet. In 
setting this train up. it should stop so that the warning pin 
O should be near the fly. 

As all the parts are operated by springs on the arbor, as 
shown by the hammicr spring II, it wi.l be seen that this 
strike mechanism will wcrk in any position, while that 
w^hich is operated by gravity must be kept upright. A 
loose fly will cause the clock to strike too fast and may 
cause it to strike wrong. Careless adjustment of the rack 
tail T with the snail will also induce wrong counting, 
although this is somewhat easier to adjust than the English 
form of strike. The hock should safely clear the rack 
teeth just as the gathering pallet G lets go of a tooth. If 
attention is paid to this point in adjusting the rack tail 
there will generally be little trouble. 



THE MODERX CLOCK. 



3^5 



The cam bearing the pins J K on the center arbor may be 
shifted with a pair of pliers to secure accurate register of 
hands and strike, as is the case with most American strikes. 
In putting in the pin wheel it should be set so that the pins 
may have a little run be fere striking the hammer tail, as 




Fig. 109. Train about to strike the half hour; the hook 1/ free of the 
train, which is held by the warning pin O ; one stroke will be given 
when M drops. 



this hammer tail is very short, and if the spring is strong 
the pins may not be able to lift the hammer tail without 
sufficient run to get the train thoroughly under motion. 
The half-hour strike should also be tested so that the pin J 
will release the warning pin O from the lever M without 
releasing the rack hook from the rack, as shown in Fig. 



346 



THE MODERN CLOCK. 



109. The parts of the train when at rest will be readily 
discerned in Fig. 108, where the hook L has locked the 
train by the pin N and the freedom between the pins and 
the hammer tail is about what it should be. 




Fig. 110. Train unloclted and running. Xote position of L and M. 



The relative position of the locking lever L and the rack 
hook is also very clearly shown in Fig. 108; that is, when 
the rack hook is pressed clear home at the lower notch of 
the rack, the lever L should safely lock the train and the 
lever M be resting with its link against the center arbor. 



CHAPTER XIX. 

THE CONSTRUCTION OF SIMPLE AND PERPETUAL CALENDARS. 

In taking up the study of calendar work the first thing 
that the student observes is the irregularity of motion of 
the various members. Every other portion of a clock has 
for its main object the attainment of the nicest regularity 
of motion, while the calendar must necessarily have irreg- 
ular motion. The hand of the day of the month proceeds 
around its dial regularly from i to 28 and then jumps t^ 
I in February of some years, while it continues to 29 iii 
others; sometimes it revolves regularly from I to 31 for 
several revolutions and then jumps from 30 to i. What is 
the reason of this? 

If the moon's phases are shown they do not agree with 
the changes of the month wheels, but keep gaining on them, 
while if an "equation of time" is shown, we have a hand 
that moves irregularly back and forth from the Figure XII 
at the center of its dial. What is the cause of this gaining 
and losing? 

In order to understand this mechanism properly we shall 
have to first know what it is intended to show and this 
brings us to the study of the various kinds of calendar. 

The earth revolves about its axis with a circular motion; 
it revolves about the sun with an elliptical motion. This 
means that the earth will move through a greater angular 
distance, measured from the sun's center, in a given time at 
some portions of its journey than it will do at others; at 
times the sun describes an arc of 57 minutes of the ecliptic ; 
at other times an arc of 61 minutes in a day; hence the sun 
will be directly over a given meridian of the earth (noon) 

347 



348 THE MODERN CLOCK. 

a little sooner at some periods than at others. Now the 
time at which the sun is directly over the given meridian is 
apparent noon, or solar noon. As before stated, this is ir- 
regular, while the motion of our clocks is regular, conse- 
quently the sun crosses the meridian a little before or a 
little after twelve by the clock each day, varying from 15 
minutes before twelve to 15 minutes after twelve by the 
clock. The best we can do under these circumstances is to 
divide these differences of gaining or losing, take the aver- 
age or mean of them and regulate the clock to keep mean 
time. Here then we have two times — the irregular appar- 
ent time and the regular mean apparent time. The amount 
to be added to or subtracted from the mean in order to get 
the solar or actual apparent time is called the equation of 
time and this is shown by the equation hand on an astro- 
nomical or perpetual calendar clock. 

The moon revolves on its axis with a circular motion and 
it revolves about the earth with an elliptical motion, the 
earth being at one focus of the ellipse ; as this course does 
not agree with that of the sun, but is shorter, it keeps gain- 
ing so that the lunar months do not agree with the solar. 

Certain stars are so far away that they apparently have 
no m.otion of their own and are called iixed; hence in ob- 
serving them the only motion we can discern is the circular 
m^oticn of the earth. We can set our clocks by watching 
such stars and a complete revolution of the earth, measured 
by such a star, is called an asfronomieal or siderial 'day. 
This is the one used in computing all our time. It is shorter 
than the mean solar .day by 3 minutes 56 seconds. 

A year is defined as the period of one complete revolu- 
tion of the earth about the sun, returning to the same start- 
ing point in the heavens. By taking different starting 
points we are led to different kinds of years. The point 
generally taken is the vernal equinoctial point, and when 
measured thus it is called the tropical year, which gives us 
the seasons. It is 20 mjnutes shorter than the siderial year. 



THE MODERN CLOCK. 349 

A siderial year is the period of a complete revolution 
of the earth about the sun. This period is very approxi- 
mately 365 days, 6 hours, 9 minutes, 9.5 seconds of mean 
time. Here we see an important difference between the 
siderial and 'the cio'il year of 365 days, and it is this dif- 
ference, which must be accounted for someliow, that causes 
the irregularities in our calendar work. 

For ordinary and business purposes the public demands 
that the year shall contain an exact number of days and 
that it should bear a simple relation to the recurrence of the 
seasons. For this reason the civil year has been introduced. 
The Roman emperor, Julius Caesar, ordered that three suc- 
cessive years should have 365 days each and the fourth^ 
year should have 366 days. 

The fourth year, containing 366 days, is called a leap 
year, because it leaps over, or gains, the difference between 
the civil and siderial time of the preceding three years. For 
convenience the leap year was designated as any year whose 
number is exactly divisible by 4. This is called the Julian 
calendar. 

But as a siderial year is 365 days, 6 hours, 9 minutes, 
9.5 seconds of mean time, the addition of one day of twen- 
ty-four hours would not exactly balance the two calendars ; 
therefore Pope Gregory XIIL, in 1582, ordered that every 
year whose number is a multiple of 100 shall be a year of 
365 days, unless the number of the year is divisible by 400, 
when it shall be a leap year of 366 days. 

The calendar constructed in this way is called the Gre- 
gorian calendar, and is the one in common use. Its error 
is very small and will amount to only i day, 5 hours, 30 
minutes in 4,000 years. 

The revolution of the moon around the earth in relation 
to the stars, takes place in 2"/ days, 7 hours and 43 minutes ; 
this is called a siderial month. But during this period the 
earth has advanced along the plane of its path about the sun 
and the moon must make up this distance in order to re- 



35° 



THE MODERN CLOCK. 



turn to the same point in relation to the sun. This period 
is called a synodic month. Its average length is 29 days, 
12 hours, 44 minutes, 2.9 seconds. 

Having now understood these differences we shall be 
able to intelligently examine the various calendar mechan- 
isms on the market and understand the reasons for their 
apparent departures from regular mechanical progression, 
as the equation of time gives us the difference between real 
and mean apparent, or solar time; we regulate our clocks 
by means of siderial time; the irregular procession of 30 
and 31 days makes the civil calendar agree with the seasons, 
or the tropical year, and the remainder of the discrepancy 
between civil and siderial time is made up in February at 
the period when it is of the least consequence. 

Simple Calendar Work. — Fig. iii shows the Ameri- 
can method of making a simple calendar, the example 
shown being drawn from a movement of the Waterbury 
Clock Company as a typical example. A'o attempt is made 
here to show the day of the week or the month. The days 
of the month are shown by a series of numbers from i to 31, 
arranged concentrically with- the tim.e dial and the current 
day is indicated by a hand of different color, carried on a 
pipe outside the pipe of the hour hand on the center arbor. 

In order to accomplish this the motion work for the 
hands is mounted inside the frames, the hour pipe and 
center arbor being suitably lengthened. In the Figure A 
is the cannon pinion ; B, the minute wheel ; C, the 
minute pinion ; D, the hour wheel at the rear end of 
the hour pipe; this pipe projects through the frame and 
forms a bearing in the frame for the center arbor. Fric- 
tion-tight on the hour pipe, in front of the front plate, is 
the pinion E, which drives a wheel F of twice as many 
teeth. This wheel F is mounted loosely on a stud and has 
a pin which meshes with the teeth of a ratchet wheel G. G 
is carried at the bottom end of a pipe which fits loosely on 



THE MODIiltX CLOCK. 



351 





Fig. 111. Simple calendar on time train. 



352 THE MODERN CLOCK. 

the hour pipe and carries the calendar hand H under the 
hour hand and close to the dial. The pinion on the hour 
pipe revolves once in twelve hours. The wheel E has twice 




yig. 112. Calendar work for grandfather clocks. 

as many teeth and will therefore revolve once in twenty- 
four hours. It moves the ratchet G one tooth at each revo- 
lution ; therefore the hand H moves one space every twenty- 
four hours. There arc 31 teeth, so that the hand must be 
set forward every time it reaches the 28th and 29th of Feb- 



THE MODERN CLOCK. 353 

ruary and the 30th of April, June, September and Novem- 
ber. This is the simplest and cheapest of all the calendars, 
occupies the least space and is frequently attached to nickel 
alarm clocks for that reason. 

A simple calendar work often met with in old clocks of 
European origin is shown in Fig. 112. Gearing with the 
hour wheel is a wheel, A, having twice its number of 
teeth, and turning therefore once in twenty-four hours. A 
three-armed lever is planted just above this wheel; the 
lower arm is slotted and the wheel carries a pin which 
works in this slot, so that the lever vibrates to and fro once 
every twenty-four hours. The three upper wheels, B, C 
and D in the drawing, represent three star wheels. B has 
seven teeth, corresponding to the days of the week; C has 
31 teeth, for the days of the month; and D has 12 teeth, 
for the months of the year. Each carries a hand in the 
center of a dial on the other side of the plate. Every time 
the upper arms of the lever vibrate they move forward the 
day of the week, B, and the day of the month, C, wheels 
each one tooth. The extremities of the two upper levers 
are jointed so as to yield on the return vibration, and are 
brought into position again by a weak spring. There is a 
pin in the wheel, C, which, by pressing on a lever once 
every revolution, actuates the month of the year wheel, D. 
This last lever is also jointed, and is pressed on by a spring 
so as to return to its original position. Each of the star 
wheels has a click kept in contact by means of a spring. 
For months with less than 31 days, the day of the month 
hand has to be shifted forward. 

Perpetual Calendar Work. — Figs. 113, 114, 115, show 
a perpetual calendar which gives the day of the week, day 
of the month and the month, making all changes automati- 
cally at midnight, and showing the 31 days on a dial be- 
neath the time dial, by means of a hand, and the days of 
the week and the month by means of cylinders operating 



■354 



THE MODERN CLOCK. 




-O 


A^>K 


IP 1 






'tS^^^^^E-T^^ ^ 


- 


IIP'J ■ 





r^ 



-jK 



ii:0 



Fig. 113. Perpetual Calendar Movement. 



THE MODERN CLOCK. 353 

behind slots in the dial on each side of the center. This 
is also a Waterbury movement. ' 

A pinion on the hour pipe engages a wheel, A, having 
twice the number of teeth and mounted on an arbor which 
projects through both plates. The rear end of this arbor 
carries a cam, B, on which rides the end of a lever, C, which 
is pivoted to the rear frame. The lever is attached to a 
wire, D, which operates a sliding piece, E, which is weight- 
ed at its lower end. The cam, \yhich, of course, revolves 
once in twenty- four hours, drops its lever at midnight and 
the weight on E pulls it down. E bears a spring pawl, F, 
which on its way down, raises the spring actuated retaining 
click, H, and then moves the 31 -toothed wheel G one notch. 
This wheel is mounted on the arbor which carries the hand 
and, of course, advances the hand. 

Lying on top of the wheel, G, is a cam, I, pivoted to G 
near its circumference and having an arm reaching toward 
the months cylinder and another reaching towards the right 
leg of the pawl, H, while it is cut away in the center, so as 
to clear the center arbor carrying the hand. Trace this cam, 
I, carefully in Figs. 113 and 114, as its action is vital. The 
lower arm of this cam is shown more clearly in Fig. 114. 
It projects above the wheel and engages the long teeth, J, 
and the cam, K, mounted on the year cylinder arbor; 
where the lower arm of I strikes one of these teeth it shoves 
the upper arm outward, so that it strikes the retaining end 
of the pawl, H, and holds it up, and the descending pawl, 
F, may then push the wheel, G, forward for more than one 
tooth. The upper end of I is broad enough to cover three 
teeth of the wheel, G, when pushed outward, and the slot 
in E is long enough so that F may descend far enough to 
push G forward three teeth at once, unless it is stopped by 
H falling into a tooth, so that the position of I, when it is 
holding up H and the extra drop thus given to E serve to 
operate the jumps of 30 to i, 28 to i and 29 to i of the hand' 
on the dial. The teeth, J, Fig. 1 14, operate for two notches, 



35^ 



THE MODERN CLOCK, 




Fig. 114. The months change gear. 



THE MODERN CLOCK. ^fi^^ 

thus making the. changes from 30 to i. The wide tooth, M, 
and cam, K, acting together, make the change for February 
from 28 to 31. The 29th day is added by the movement of 
the cam, K, narrowing the acting surface once in four years, 
as follows: 

Looking at Fig. 114 we see an ordinary stop works fin- 
ger, mounted on the months arbor and engaging a four- 
armed maltese cross on the wheel. Behind the wheel is a 
circular cam (shown dotted in) with one-fourth of its cir- 
cumference cut away; the pivot holds the cam and cross 
rigidly together while permitting them to revolve loosely in 
the wheel. The cam, K, lies close to the w^heel and is 
pressed against the cam on the cross by a spring, so that 
ordinarily the full width of M and K act as one piece on 
the end of the cam, I, which thus is pressed against the 
retaining pawl, H, during the passage of three teeth, mak- 
ing the jump from 28 to i each of these three years. 

The fourth revolution of the maltese cross brings the cut 
portion of its cam to operate on K and allows K to move 
tehind M, thus narrowing the acting surface so that I only 
covers two teeth (30 and 31) for every fourth revolution 
of the month's cylinder, thus making the leap year every 
fourth year. 

The months cylinder is kept in position by the two-armed 
pawl, N, engaging the teeth, L, which stand at 90 degrees 
from the wheel, as shown in Fig. 113. Attached to the 
bearing for the week cylinder (not shown) is one revolu- 
tion of a screw track, or worm, surrounding the arbor for 
the hand. Attached to the arbor is a finger, O, held taut 
by a spring and engaging the track, P. The revolution of 
the arbor raises O on P until it slips off, when O, drawn 
downward by its spring, raises the pawl, N, drops on one 
of the teeth, L, and revolves the cylinder one notch. 

Q is a shifter for raising the pawl, H, and allowing the 
hand to be set. 



358 



THE MODERN CLOCK. 




Fig. 115. The weeks chaage gear. 



THE MODERN CLOCK. 3.^^ 

Fig. 115 shows the inner end of the cyHnder for the days 
of the week. There are two sets of these and fourteen 
teeth on the sprocket, R, so as to get the two cyHnders ap- 
proximately the same size (there being 14 days and 12 
months on the respective cyHnders). S is a pawl whose 
upper end is forked so as to embrace a tooth and hold the 
cylinder in position. T is a hook, carried on the sliding 
piece, E, which swings outward in its upward passage as E 
is raised and on its downward course raises the pawl, S, 
and revolves the sprocket, R, one tooth, thus changing the 
day of the week at the same time the hand is advanced. 

To set the calendar, raise the pawl, N, and revolve the 
year cylinder until M and K are at their narrowest width ; 
that is, a leap year. Then give the year cylinder as many 
additional turns as there are years since the last leap year, 
stopping on the current month of the current year. For 
instance, if it is two years and four months since the 29th 
of February last occurred, give the cylinder 2 and 4/12 
turns which should bring you to the current month, raise 
the shifter, Q, and set the hand to the current day. Then 
raise the pawl, S, and set the week cylinder to the current 
day. Place the hour hand on the movement so that the cam 
will drop E at midnight. 

Fig. 116 shows the dial of Brocot's calendar work, which, 
with or without the equation of time and the lunations, is 
to be met with in many grandfather, hall and astronomical 
clocks. We will assume that all of these features are pres- 
ent, in order to completely cover the subject. It consists of 
two circular plates of which the front plate is the dial and 
the rear plate carries the movement, arranged on both sides 
of it. All centers are therefore concentric and we have 
marked them all with the same letters for better identifica- 
tion in the various views as the inner plate is turned about 
to show the reverse side, thus reversing the position of right 
to left in one view of the inner plate. 



360 



THE MODERN CLOCK. 



Fig. 117 shows the wheel for the phases of the moon, 
which is mounted on the outside of the inner plate imme- 
diately behind the opening in the dial. The dark circles 
h'ave the same color as the sky of the dial and the rest is 
gilt, white or cream color to show the moon as in Fig. 116. 



\ \ i 



^ V \ ^ ' • I ' ' ' / / -\ 



y v<>^e*t^ ^^"'^-^^ 




Fig. 116. Dial of Brocot's Calendar. 



The position of this plate is also shown in Fig. 120. By 
the dotted circles, about the center D. 

The inner side containing the mechanism for indicating 
the days of the week and the days of the month is shown in 
Fig. 118. The calendar is actuated by means of a pin, C, 
fixed to a wheel of the movement which turns once in 
twenty-four hours in the manner previously described with 



THE MODEUN CLOCK. 361 

Fig. 113. Two clicks, G and H, arc pivoted to the lever, 
M. G, by means of its weighted end, see Fig. 119, is kept 
in contact with a ratchet wdieel of 31 teeth, and H with a 
ratchet wheel of 7 teeth. As a part of these clicks and 
wheels is concealed in Fig. 118, they are shown separately 
in Fig. 119. 

When the lever, AI, is moved to the left as far as it will 
go by the pin, e, the clicks, G and H, slip under the teeth ; 
their beaks pass on to the following tooth ; when e has 
moved out of contact the lever, M, falls quickly by its own 
weight, and makes each click leap a tooth of the respective 
wheels, B of 7 and A of 31 teeth. The arbors of these 
wheels pass through the dial (Fig. 116), and have each an 
index which, at every leap of its own wheel, indicates on its 
special dial the day of the week and the day of the month. 
A roll, or click, kept in position by a sufficient spring, keeps 
each wheel in its place during the interval of time which 
separates two consecutive leaps. 

This motion clearly provides for the indication of the day 
of the week, and would be also sufficient for the days of 
the month if the index were shifted by hand at the end of 
the short months. 

To secure the proper registration of the months of 30 
days, for February of 28 during three years, and of 29 in 
leap year, we have the following provision : The arbor, A, 
of the day of the month wheel goes through the circular 
plate, and on the other side is fixed (see Fig. 120) a pinion 
of 10 leaves. This pinion, by means of an intermediate 
wheel, I, works another w^heel (centered at C) of 120 
teeth, and consequently turning once in a year. The arbor 
of this last wheel bears an index indicating the name of the 
month, G, Fig. 116. The arbor, C, goes through the plate, 
and at the other end, C, Fig. 118, is fixed a little wheel 
gearing with a wheel having four times as many teeth, and 
which is centered on a stud in the plate at F. This wheel 
is partly concealed in Fig. 118 by a disc V, which is fixed 



362 THE MODERN CLOCK. 

to it, and with the wheel makes one turn in four years. On 
this disc, V, are made 20 notches, of which the 16 shallow- 
est correspond to the months of 30 days ; a deeper notch 
corresponds to the month of February of leap year, and the 
last three deepest to the month of February common years 
in each quarternary period. The uncut portions of the disc 
correspond to the months of 31 days in the same period. 
The wheel. A, of 31 teeth, has a pin (i) placed before the 
tooth which corresponds to the 28th of the month. On the 
lever, M, is pivoted freely a bell-crank lever (N), having at 




Fig. 117. Dial of Moon's Phases. 

the extremity of the lower arm a pin (o) which leans its 
own weight upon the edge of the disc, V, or upon the bot- 
tom of one of the notches, according to the position of the 
month, and the upper arm of N is therefore higher or lower 
according to the position of the pin, o, upon the disc. 

It will be easy to see that when the pin, o, rests on the 
contour of the disc the upper arm, N, of the bell-crank 
lever is as high as possible, and out of contact with the pin 
as it is dotted in the figure, and then the 31 teeth of the 
month wheel will each leap successively one division by the 
action of the click, G, as the lever, M, falls backward till 
the 31st day. But when the pin, o, is in one of the shal- 
low notches of the plate, V, corresponding to the months of 
30 days, the upper arm, N, of the bell-crank lever will take 



THE MODERN CLOCK. 



363 




Fig. 118. Brocot's Calendar; Rear View of Calendar Plate showing 
Four Year Wheel and Change Mechanism, 



364 



THE MODERN CLOCK. 



a lower position, and the inclination that it will have by the 
forward movement of the lever, M, will on the 3Qth bring 
the pin, i, in contact with the bottom of the notch, just as 
the lever, M, has accomplished two-thirds of its forward 
movement, so the last third will be employed to make the 
wheel 31 advance one tooth, and the hand of the dial by 
consequence marks the 31st, the quick, return of the lever, 
M, as it falls putting this hand to the ist by the action of 
the click, G. If we suppose the pin, o, is placed in the shal- 




Fig. 119. Change Mechanism behind the Four Year Wheel in Fig. 118 



lowest of the four deep notches, that one for February of 
leap year, the upper end of the arm, N, will take a position 
lower still, and on the 29th the pin, i, will be met by the 
bottom of the notch, just as the lever has made one-third of 
its forward course, so the other two-thirds of the forward 
movement will serve to make two teeth of the wheel of 31 
jump. Then the hand of the dial, A, Figs. 116 and 118, 
will indicate 31, and the ordinary quick return of the lever, 
M, with its detent, G, will put it to the 1st. Lastly, if, as 
it is represented in the figure, the pin, o, is in one of the 
three deepest notches, corresponding to the months of Feb- 
ruary in ordinary years, the pin will be in the bottom of 



THE MODERN CLOCK. 365 

the notch on the 28th just at the moment the lever begins 
its movement, and three teeth will pass before the return 
of the lever makes the hand leap from the 31st to the ist. 

The pin, 0, easily gets out of the shallow notches, which, 
as will be seen, are sloped away to facilitate its doing so. 
To help it out of the deeper notches there is a weighted 
finger (j) on the arbor of the annual wheel. This finger, 
having an angular movement much larger than the one of 
the disc, V, puts the pin, o, out of the notch before the notch 
has sensibly changed its position. 

Phases of the Moon. — The phases of the moon are ob- 
tained by a pinion of 10, Fig. 120, on the arbor, B, which 
gears with the wheel of 84 teeth, fixed on another of 75, 
Avhich last gears with a wheel of 113, making one revolu- 
tion in three lunations. By this means there is an error 
only of .00008 day per lunation. On the wheel of 113 is 
fixed a plate on which are three discs colored blue, having 
between them a distance equal to their diameter, as shown, 
in Fig. 117, these discs slipping under a circular aperture 
made in the dial, produce the successive appearance of the 
phases of the moon. 

Equation of Time. — On the arbor of the annual wheel, 
C, Figs. 116, 118, 120, is fixed a brass cam, Y, on the edge 
of which leans the pin, s, fixed to a circular rack, R. This 
rack gears with the central wheel, K, which carries the 
hand for the equation. That hand faces XII the 15th of 
April, 14th of June, ist of September and the 25th of De- 
cember. At those dates the pin, s, is in the position of the 
four dots marked on the cam, Y. The shape of the cam, 
Y, must be such as will lead the hand to indicate the dif- 
ference between solar and mean time, as given in the table 
of the Nautical almanac. 

To set the calendar first see that the return of the lever, 
M, be made at the moment of midnight. To adjust the 
hand of the days of the week, B, look at an almanac and 



366 



THE MODERN CLOCK. 



see what day before the actual date there was a full or new 
moon. If it was new moon on Thursday, it would be nec- 
essary, by means of a small button fixed at the back, on the 
arbor of the hand of the wheel, B, of the week, to make as 
many returns as requisite to obtain a new moon, this hand 



S'/T 




s-m^- 



Fig. 120. Brocot's Calender: "Wheels and Pinions under the Dial with 
their Number of Teeth. 



pointing. to a Thursday; afterward bring back the hand to 
the actual date, passing the number of divisions correspond- 
ing to the days elapsed since the new moon. To adjust the 
hand of the day of the month, A, see if the pin, o, is in the 
proper notch. If for the leap year, it is in the month of 
February in the shallowest of the four deep notches (o) ; 
if for the same month of the first year after leap year, then 
the pin should be, of course, in the notch, i, and so on. 



CHAPTER XX. 

HAMMERS, GONGS AND BELLS. 

Just as the tone of a piano depends very largely upon the 
condition of the felts on the hammers which strike the 
wires, so does the tone of a clock gong or bell depend on 
its hammer action. The deep, soft, resonant tone in either 
instance depends on the vibration being produced by some- 
thing softer than metal. Ordinarily this condition is reached 
by facing the hammer with leather. The second essential 
is that the hammer shall immediately rebound, clear of the 
bell, so as not to interfere with the vibrations it has set up 
in the bell, wire or tube. As the leather gets harder the 
tone becomes harsher and ''tinny," sometimes changing to 
another much higher tone and entirely destroying the 
harmony. The remedy is either to oil the leather on the 
hammers, or if they are much worn to substitute new and 
thicker leathers until the tone is sufficiently mellowed, so 
that a vigorous blow will still produce a mellow tone of 
sufficient carrying power. A piece of round leather belting 
will be found very convenient for this purpose. 

The superiority of a chiming clock lies in its hammer 
action. If this mechanism is not perfect, only inferior re- 
sults can be obtained. The perfect hammer is the one that 
acts with the smallest strain and is operated with the least 
power. Heavy weights create a tremendous strain on the 
mechanism and bring disastrous results when one of the 
suspending cords break. The method of lifting the ham- 
mer is one of importance, and the action of the hammer 
spring is but seldom right on old clocks brought in for re- 
pairs, especially if it be a spring bent oyer to a right angle 

367 



368 THE MODERN CI.OCK. 

at its point. If there are two springs, one to force the ham- 
mer down after the clock has raised it up, and another 
shorter one, fastened on to the pillar, tO' act as a counter- 
spring and prevent the hammer from jarring on the bell, 
there will seldom be any difficulty in repairing it; and the 
only operation necessary to be done is to file worn parts, 
polish the acting parts, set the springs a little stronger, and 
the thing is done. But if there is only one spring some 
further attention will be necessary, because the action of the 
one spring answers the purpose of the two previously men- 
tioned, and to arrange it so that the hammer will be lifted 
with the greatest ease and then strike on the bell with the 
greatest force, and without jarring, requires some experi- 
ence. That part of the hammer-stem which the spring acts 
on should never be filed or bent beyond the center of the 
arbor, as is sometimes done, because in such a case the ham- 
mer-spring has a sliding motion when it is in action, and 
some of the force of the spring is thereby lost. The point 
of the spring should also be made to work as near to the 
center of the arbor as it is possible to get it, and the flat 
end of the spring should be at a right angle with the edge 
of the frame, and that part of the hammer-stem that strikes 
against the flat end of the spring should be formed with a 
curve that will stop the hammer in a particular position and 
prevent it jarring on the bell. This curve can only be deter- 
mined by experience ; but a curve equal to a circle six inches 
in diameter will be nearly right. 

The action of the pin wheel on the hammer-tail is also 
of importance. The acting face of the hammer-tail should 
be in a line with the center of the pin-wheel, or a very little 
above it, but never below it, for then it becomes more dif- 
ficult for the clock to lift the hammer, and the hammer- 
tail should be of such a length as to drop from the pins of 
the pin-wheel, and when it stops be about the distance of 
two teeth of the wheel from the next pin. This allows the 
wheel- work to gain a little force before lifting the hammer, 



THE MODERN CLOCK. 369 

which is sometimes desirable when the clock is a little dirty 
or nearly run down. We might also mention that in set- 
ting the hammer-spring to work with greater force it" is 
always well to try and stop the fly with your finger when 
the clock is striking, and if this can be done it indicates 
that the hammer spring is stronger than the striking power 
of the clock can bear, and it ought to be weakened, because 
the striking part will be sure to stop whenever the clock 
gets the least dirty. 

Gong wires are also the cause of faulty tones. In the 
factories these are made by coiling wires of suitable lengths 
and sections on arbors in a lathe. They are then heated to 
a dull red and hardened by dipping in water or oil. After 
cooling they are trued in the round and the flat like a watch 
hairspring and then drawn to a blue temper. The tone 
comes with the tempering, and if they are afterwards bent 
beyond the point where they will spring back to shape the 
tone is interfered with. Many repairers, not being aware 
of this fact, have ruined the tone of a gong wire while try- 
ing to true it up by bending with pliers. When the owner 
is particular about the tone of the clock, a new gong should 
always be put in if the old one is badly bent. 

The wires are soldered to their centers and if they are 
at all loose they should be refastened in the same manner 
if it can be done without drawing the temper of the wire. 
When this cannot be done a plug of solder may be driven 
in between the wire and the side of the hole so as to stop 
all vibration or the solder already in place may be driven 
down so as to make all tight, as any vibration at this point 
will interfere with the tone. 

Tuning the Bells. — Bells only vefy slightly out of 
tone offend the musical ear, and they may easily be correct- 
ed to the extent of half a tone. To sharpen the tone make 
the bell shorter by turning away the edge of it if it be a 
shell, or by cutting off if it be a rod or tube ; to flatten the 



370 



THE MODERN CLOCK. 



-T1C10D 



^. 



%i 



it 



3; 



^ 



2c 



i=iE 



5E 



■rJ 



yi 



>1 



Fig. 121. The pins in the chiming barrels. 



THE MODERN CLOCK. 37t 

tone, thin the back basin-shaped part of the bell by turn- 
ing some off the outside. Bells which are cracked give a 
poor sound because the edges of the crack interfere with 
each other when vibrating. They may be repaired by saw- 
ing through the crack to the end of it, so that the edges will 
not touch each other when vibrating. If there is danger of 
the crack extending further into the bell, first drill a round 
hole in the soHd metal just beyond the end of the crack, 
and then saw through into the hole ; this will generally pre- 
vent any further trouble. 

Marking the Chime Barrel. — The chime barrel in 
small clocks is of brass and should be as large in diameter 
as "can be conveniently got in. To mark off the positions of 
the pins for the Cambridge chimes, first put the barrel in 
the lathe and trace circles round the barrel at distances 
apart corresponding to the positions of the hammer tails. 
There are five chimes of four bells each for every rotation 
of the barrel, and a rest equal to two or three notes be- 
tween each chime. Assuming the rest to be equal to three 
notes, divide the circumference of the barrel into thirty- 
five equal parts by means of an index plate, and draw lines 
at these points across the barrel with the point of the tool 
bv moving it with the slide rest screw. Call the hammer 
for the highest note D, and that for the lowest note F. 
Then the first pin is to be inserted where one of the lines 
across the barrel crosses the first circle; the second pin 
where the next line crosses the second circle; the third pin 
where the third line crosses the third circle and the fourth 
pin where the fourth line crosses the four circle, because 
the notes of the first chime are in the order, D, C, Bb, F. 
Then miss three lines for the rest. The first note of the 
second chime is Bb and the pins for it will consequently be 
inserted where the first line after the rest crosses the third 
circle, and so on. Where two or more notes on the same 
bell come so close as to make it difficult to strike them prop- 



372 



THE MODERN CLOCK. 



erly, it is usual to put in another hammer, as it shown in 
Fig. 121, where there are two Fs. In fine clocks the pins 
are of varying lengths so as to strike the hammers on the 
bells with varying force and thus give more expression to 
the music. 

The following gives the Cambridge Chimes, which are 
used in the Westminster Great Clock. They are founded 
on a phrase in the opening symphony of Handel's air, 'T 



1st 
Quarter 

2nd . 
Quarter. 

3rd 
Quarter. 



^ 



^ 



^s 



t 



i 



^ 



^ 



3te 



22: 



■ f^^^M^gJfFF ? ^! 



Hour. 



i 



&i 



m^- 



i3t 



^^^ 



$ 



t 



^^ 



22: 



H^M 



Fig. 122. Westminster chimes. 



know that my Redeemer liveth," and were arranged by Dr. 
Crotch for the clock of Great St. Mary's, Cambridge, in 
1793- 

In Europe these chiming clocks are sometimes very elab- 
orate, as the following description of a set of bells in Bel- 
gium will show: 

"So far as the experience of the writer goes the Belgian 
carillons are invariably constructed on one prevailing plan, 
with the exception that the metal used for the cylinder is 
generally brass; here, however, it is of steel, and consists 
of a large barrel measuring 4 feet 2 inches in width and 3 



THE MODERN CLOCK. 373 

feet 6 inches in diameter, its surface being pierced with 
horizontal lines of small square holes about ^ inch square. 
There are lines of 60 of these in the width of the barrel, 
while there are 120 lines of them round the circumference, 
making a total of 7,200 holes. The drilling of these, of 
course, takes place when the cylinder is made, and, so far 
as this part is concerned, the barrel is complete before it is 
brought to the tower. 

"Into these square holes are fixed the 'pins,' adjusted on 
the inside of the cylinder by nuts. 

"The pins are of steel of finely graduated sizes, corres- 
ponding with the value of the notes of music. Some idea 
of the precision obtainable may be gathered by the fact, as 
the carillonneur told the writer, that there were no less 
than 24 grades of pins, so as to insure the greatest accuracy 
of striking the bells. 

"Over the cylinder are 60 steel levers with steel nibs; 
these are lifted by the 'pins' and, connected by wires with 
the hammers, strike the bells. 

"The 35 bells are furnished with J2 hammers, which are 
fixed as ordinary clock-hammers outside of the bells; three 
of the bells (in the ring of eight) have a single hammer 
only, the limited space in the 'cage' making it impossible 
to put more, while others are supplied with two or three 
apiece for use in rapidly repeating notes of the music. On 
a visit some years ago to the carillon at Malines, the writer 
noticed that some of the bells there had no less than five 
hammers apiece. 

"Obviously, though there are 'J2 hammers in connection 
with the carillon, only 60, corresponding with the number 
of levers, can be used at one time; these are selected ac- 
cording to the requirement of the tune; in case of new 
tunes, the wires can easily be adjusted so as to bring other 
hammers and bells into use. 

"The feature of the Belgian carillons is that instead of 
the single notes of the air being struck as with the old 



374 '^^^E MODERN CLOCK. 

familiar 'chimes/ harmonized tunes of great intricacy are 
rendered with chords of three, four or even five bells strik- 
ing at one time. 

"The cylinder here is capable of 120 'measures' of music, 
but^as „ a matter of fact it is subdivided so that half a revo- 
lution plays every hour. 

"A march is, as a rule, played at the odd hours, and the 
national air at the even, but the bells are silent after 9 p. m. 
and start again at 8 a. m. 

"The motive power is supplied by a weight of 8 cwt., 
and is controlled by a powerful fly of four fans artistically 
formed to represent swans. It may be mentioned that the 
keyboard for hand-playing consists of thirty-five keys of 
wood and eleven pedals; these, as indeed the whole appa- 
rartus of this part, are entirely separate from the automatic 
carillon ; in this instance the keys connect with the clappers 
of the bells and have no association with the hammers. 
The pedals are connected with the eleven largest bells and 
are supplementary to the hour key." 

Tubular Chimes are tubes of bell metal, cut to the 
proper lengths to secure the desired tones and generally, 
but not always, nickel plated. As they take up much room 
in the clock, they are generally suspended from hooks at 
the top of the back board of the case, being attached to the 
hooks by loops of silk or gut cords, passed through holes 
drilled in the wall of the tubes near the top ends. The hour 
tube, being long and large, generally extends nearly to 
the bottom of a six-foot case, while the others range up- 
wards, shortening according to the increase of pitch of the 
notes which they represent. 

This makes it necessary to place the movement on a seat 
board and hang the pendulum from the front plate of the 
movement, so that such clocks have, as a rule, comparative- 
ly light pendulums. On account of the position and the 
great spread of the tubes, the chiming cylinder and ham- 
mers are placed on top of the movement, parallel with the 



TIIF MODERN CLOCK. 375 

plates, and operated from the striking train by means of 
bevel gears or a contrate wheel. The hammers are placed 
vertically on spring hammer stalks and connected with the 
chiming cylinder levers by silken cords. This gives great 
freedom of hammer action and results in very perfect tones. 
The hammers must of course be each opposite its own 
tube and thus they are rather far apart, which necessitates 
a long cylinder. This gives room for several sets of 
chimes on the same cylinder if desired, as a very slip^ht 
horizontal movement of the cylinder would move the pins 
out of action with the levers and bring another set into 
action or cause the chimes to remain silent. 

Practically all of the manufacturers of "hall" or chim- 
ing clocks import the movements and supply American 
cases, hammers and bells. The reason is that there is so 
little sale for them (from a factory standpoint) that one 
factory could supply the world with movements for this 
class of clocks without working overtime, and therefore it 
would be useless to make up the tools for them when they 
can be bought without incurring that expense. 



CHAPTER XXL 

ELECTRIC CLOCKS AND BATTERIES. 

Electric clocks may be divided into three kinds, or prin- 
cipal divisions. Of the first class are those in which the 
pendulum is driven directly from the armature by electric 
impulse, or by means of a weight dropping on an arm pro- 
jecting from the pendulum. In this case the entire train of 
the clock consists of a ratchet wheel and the dial work. 

The second class comprises the regular train from the 
center to the arbor. This class has a spring on the center 
arbor, wound more or less frequently by electricity. In 
this case the aim is to keep the spring constantly wound, so 
that the tension is almost as evenly divided as with the 
ordinary weight clock, such as is used in jewelers' regu- 
lators. 

The third system uses a weight on the end of a lever 
connected with a ratchet wheel on the center arbor and . 
does away with springs. One type of each of these clocks 
will be described so that jewelers may comprehend the prin- 
ciples on which the three types are built 

In the Gillette Electro-Automatic, which belongs to the 
class first mentioned, the ordinary clock principle is re- 
versed. Instead of the works driving the pendulum, the 
pendulum drives the train, through the medium of a pawl 
and ratchet mechanism on the center arbor. The pendu- 
lum is kept swinging by means of an impulse given every 
tenth beat by an electro-magnet. This impulse is caused 
by the weight of the armature as it falls away from the 
magnet ends, the current being used solely to pull back and 
re-set the armature for the next impulse. Any variation in 
the current, therefore, does not affect the regulation of the 

376 



THE MODERN CLOCK 



377 




Fig. 123. Gillette Clock (Pendulum Driven) 



378 THE MODERN CLOCK. 

clock, as the power is obtained from gravity only, by 
means of the falling weight. Referring to the drawings. 
Figs. 123 and 124, it is seen that each time the pendulum 
swings the train is pushed one tooth forward. A cam is 
carried by the ratchet (center) arbor in which a slot is pro- 
vided at a position equivalent to every fifth tooth of the 
ratchet. Into this slot drops the end of a, lever, releasing at 
its other end the armature prop. Thus at the next beat of 
the pendulum the armature is released and in its downward 
swing impulses the pendulum, giving it sufficient mo- 
mentum to carry it over the succeeding five swings. 

The action of the life-giving armature is entirely discon- 
nected and independent of the clock mechanism. It acts 
on its own accord when released every tenth beat and auto- 
matically gives its impulse and re-sets itself. It is pro- 
vided with a double-acting contact spring (see Fig. 125) 
which "flips" a contact leaf from one adjustable contact 
screw to the other as the action of the armature causes the 
spring to pass over its dead center. Thus, when the arma- 
ture reaches the lowest point in its drop (Figs. 126 and 
127) the leaf snaps against the right contact screw, the cir- 
cuit is completed, the magnet energized and the armature 
drawn up. As the armature rises above a certain point, the 
dead center of the flipper spring is again crossed and the 
leaf snaps back against the post at the left. In the mean- 
time, however, the armature prop has slipped under the end 
of the armature and retains it until the time comes for the 
next impulse. 

In adjusting the mechanism of this type of clock the in- 
creasing pendulum swing should catch and push the ratchet 
before the buffer strikes and lifts the armature from the 
prop. The adjustment of the "flipper" contact screws 
(with 1-32 inch play) should be such that as the armature 
falls the contact leaf will be thrown and the armature 
drawn up at a p9int just beyond the half-way position in 
the swing of the pendulum. The power of the impulse can 



THE MODERN CLOCK. 



379 




Fig. 124. Side View. 



3S0 THE MODERN CLOCK. 

be regulated by turning the adjusting post with pHers, thus 
varying the tension of the armature spring, the pull of 
which reinforces the weight of the armature. • Care should 
be taken, however, that the tension is not beyond the "quick 
action" power of the electro-magnet. It is much better to 
ease up the movement in other ways before putting too 
great a load on the life of the battery. 

The electrical contacts on the leaf and screw are platinum 
tipped to prevent burning by the electric sparking at the 
''make" and ''break." This sparking is also much reduced 
by means of a resistance coil placed in series connection 
with the magnet coil, Fig. 127, to reduce the amount of 
current used. If this coil is removed or disconnected the 
constant sparking and heat would soon burn out the con- 
tact tips. 

Care should be taken to see that the batteries are dated 
and the battery connections are clean at the time of sliding 
in a new battery. The brush which makes connection with 
the center or carbon post of the battery is insulated with 
mica from the framework of the case. The other connec- 
tion is made from the contact of the uncovered zinc case of 
the battery with the metal clock case surrounding it. The 
contact points should be bright and smooth to insure good 
contacts. 

These clocks need but little cleaning of the works as no 
oil whatever is used, except at one place, viz., the armature 
pivot. Oil should never be used on the train bearings, or 
other parts. This clock ran successfully on the elevated 
railway platforms of the loop in Chicago where no other 
pendulum clock could be operated on account of the con- 
stant shaking. 

In considering the electrical systems of these clocks, let 
us commence with the batteries. While undoubtedly great 
improvements have been made in the present form of dry 
battery they are still very far from giving entire satisfac- 
tion. Practically all of them are of one kind, which is 



THE MODERN CLOCK. 



3£' 



that which produces electricity at i^^ volts from zinc, car- 
bon and sal-ammoniac, with a depolarizer added to the 
elements to absorb the hydrogen. The chemical action of 
such a battery is as follows: 




/ 



Fig. 125. 

The water in the electrolite comes in contact with the zinc 
and is decomposed thereby, the oxygen being taken from 
the water by the zinc, forming oxide of zinc and leaving 
the hydrogen in the form of minute bubbles attached to 
the zinc. As this, if allowed to stand, would shut off the 
water from reaching the zinc, chemical action would there- 
fore soon cease and when this happens the battery is said 
to be polarized and no current can be had from it. 



THE MODERN CLOCK. 




THE MODERN CLOCK. 383 

In order to take care of the hydrogen and thus insure the 
constant action of the battery, oxide of manganese is added 
to the contents of the cell, generally as a mixture with the 
carbon element. Manganese has the property of absorbing 
oxygen very rapidly and of giving it off quite easily. There- 
fore while the hydrogen is being formed on the zinc, it be- 
comes an easy matter for it to leave the zinc and take its 
proper quantity of oxygen from the manganese and again 
form water, which is again decomposed by the zinc. As 
long as this cycle of chemical action takes place the battery 
will continue to give good satisfaction, and usually when a 
battery gives out it is because the depolarizer is exhausted, 
for the reason that the carbon is not affected at all and the 
zinc element forming the container is present in sufficient 
quantity to outlast the chemical action of the total mass. 

There are great differences in the various makes of bat- 
teries ; also in the methods of their construction. It would 
seem to be an easy matter for a chemist to figure out 
exactly how much depolarizer would serve the purpose 
for a given quantity of zinc and carbon and therefore to 
make a battery which should give an exact performance 
that could be anticipated. In reality, however, this is not 
the case, owing to the various conditions. There are three 
qualities of manganese in the market ; the Japanese, which 
is the best and most costly ; the German, which comes sec- 
ond, and the American, which is the cheapest and varies in 
quality so much as to be more or less a matter of guess- 
work. We must remember that in making batteries for the 
price at which they are now sold on the market we are 
obliged to take mxaterials in commercial quantities and 
commercial qualities and cannot depend upon the chemically 
pure materials with which the chemists' tlieories are always 
formulated. This therefore introduces several elements of 
uncertainty. 

In practice the Japanese manganese will stand up for a 
far longer time than any other that is known and it is 



384 THE MODERN CLOCK. 

used in all special batteries where quality and length of life 
are considered of more importance than the price. The 
German manganese comes next. Then comes a mixture of 
American and German manganese, and finally the Ameri- 
can manganese, which is used in making the cheaper bat- 
teries which are sorted afterwards, as we shall explain 
farther on. These batteries are sealed after having been 
made in large quantities, say five thousand or ten thousand 
in the lot, and kept for thirty days, after which they are 
tested. The batteries which are likely to give short-life will 
show a local action and consequent reduction of output in 
thirty days. They are, therefore, sorted out, much as eggs 
are candled on being received in a storage warehouse, for 
the reason that after a cell has been made and put together 
it would cost more to find out what was the matter with it 
and remedy that than it would to make a new cell. Many 
of the battery manufacturers, therefore, make up their bat- 
teries with an attempt to reach the highest standard. They 
are sorted for grade in thirty days and those which have 
attained the point desired are labeled as the factories' best 
battery and are sold at the highest prices. The others have 
been graded down exclusively and labeled differently until 
those which are positively known to be short-lived arc run 
out and disposed of as the factories' cheapest product under 
still another label. 

When buying batteries always look to see that the tops 
are not cracked, as if the seal on the cell is broken, chem- 
ical action induced from contact with the air as the battery 
dries out, will rapidly deteriorate the depolarizer and sul- 
phate the zinc, both of which are of course a constant draft 
on the life of the battery, which contains only a stated 
quantity of energy in the beginning. Always examine the 
terminal connections to see that they are tight and solid. 

Batteries when made up are always dated by the factory, 
but this does the purchaser little good, as the dates are in 
codes of letters, figures, or letters and figures, and are coi?,- 



THE MODERN CLOCK. 385 

stantly chang'ed so that even the dealers who are handling 
thousands of them are unable to read the code. This is 
done because many people are prone to blame the battery 
for other defects in the electrical system and many who are 
using great quantities would find an incentive to switch the 
covers on which the dates appear if they knew what it 
meant. This is perhaps rather harsh language, but a good 
many men would be tempted to send back a barrel of old 
batteries every now and then with the covers showing that 
they had not lasted three months, if they could read these 
signatures. 

Practically the only means the jeweler has of obtaining a 
good cell, with long life, is to buy them of a large electrical 
supply house, paying a good price for them and making 
sure that that house has trade enough in that battery to 
insure their being continuously supplied with fresh stock. 

The position of the battery also has to do with the length 
of life or amount of its output. Thus a battery lying on its 
side will not give more than seventy-five per cent of the 
output of a battery which is standing with the zinc and 
carbon elements perpendicular. Square batteries will not 
give the satisfaction that the round cell does. It has been 
found in practice by trials of numerous shapes and propor- 
tions that the ordinary size of 2}^x6 inches will give 
better satisfaction than one of a different shape — wider or 
shorter, or longer and thinner; that is for the amount of 
material which it contains. The battery which has proved 
most successful in gas engine ignition work is 3^x8 
inches. That maintains the same proportions as above, or 
very nearly so, but owing to local action it will give on 
clock work only about fifty per cent longer life than the 
smaller size. 

It has been a more or less common experience with 
purchasers of electric clocks to find that the batteries which 
came with the clock from the factory ran for two or three 
years (three years not being at all uncommon) and that 



386 



THE MODERN CLOCK. 



they were then unable to obtain batteries which would 
stand up to the work for more than three weeks, up to 
six months. The difference is in the quality and freshness 
of the battery bought, as outlined above. 

In considering the rest of the electrical circuit, we find 
three methods of wiring commonly used and also a fourth 
which is just now coming into use. The majority of elec- 
tric clocks are wound by a magnet which varies in size from 
three to six ohms ; bridged around the contact points, 



HM 






RbO 



w^ 



Fig. 128. 



Fig. 129. 



there has generally been placed a resistance spool which 
varies in size from ten to twenty-five times the number of 
ohms in the armature magnets. See Fig. 128. This prac- 
tically makes a closed circuit on which we are using a bat- 
tery designed for open circuit work. 

If we use an electro-magnet with a very soft iron core, 
we will need a small amount of current, but every time we 
break the contact, we will have a very high counter electro- 
motive force, leaping the air gap made while breaking the 



i 



THE MODERN CLOCK. 387 

contact and therefore burning the contact points. If our 
magnet is constructed so as to use the least current, by 
very careful winding and very soft iron cores, this counter 
electro-motive force will be at its greatest while the draft 
on the battery is at its smallest. If the magnet cores are 
rhade of harder iron, the counter electro-motive force will 
be much less ; but on the other hand much more current 
will be needed to do a given quantity of work with a mag- 
net of the second description; and the consequence is that 
while we save our contact points to some extent, we deplete 
the battery more rapidly. 

If we put in the highest possible resistance — that of air — 
in making and breaking our contacts, we use current from 
the battery only to do useful work; but we also have the 
spark from the counter electro-motive force in a form 
which will destroy our contact points more quickly. If we 
reduce the resistance by inserting a German silver wire coil 
of say sixty ohms on a six-ohm magnet circuit, we have 
then with two dry batteries (the usual number) three volts 
of current in a six-ohm magnet during work and three volts 
of current in a sixty-six ohm circuit while the contacts are 
broken, Fig. 128. Dividing the volts by the ohms, we find 
that one twenty-second of an ampere is constantly flowing 
through such a circuit. We are therefore using a dry 
battery (an open circuit battery) on closed circuit work and 
we are drawing from the life of our battery constantly in 
order to save our contact points. 

It then becomes a question which we are going to sacri- 
fice, or what sort of a compromise may be made to obtain 
the necessary work from the magnet and at the same time 
get the longest life of the contact points and the batteries. 
Most of the earHer electric clocks manufactured have finally 
arranged such a circuit as has been described above. 

The Germans put in a second contact between the bat- 
tery and the resistance with a little larger angular motion 
than. the first or principal contact, so that the contact is 



388 



THE MODERN CLOCK. 



then first made between the battery and resistance spool, B, 
Fig. 129, then between the two contact points of the shunt, 
A; Fig. 129, to the electro-magnet, and after the work is 
done they are broken in the reverse order, so that the resist- 
ance is made first and broken after the principal contact. 
This involves just twice as many contact points and it also 
involves more or less burning of the second contact. 






RbO 



w 






Fig. 130. 



Fig. 131. 



The American manufacturers seem to prefer to waste 
more or less current rather than to introduce additional 
contact points, as they find that these become corroded in 
time with even the best arrangements and they desire as 
few of them as possible in their movements, preferring 
rather to stand the draft on the battery. 

One American manufacturer inserts a resistance spool of 
60 ohms in parallel with a magnet of seven ohms (3^ ohms 
for each magnet spool) as in Fig. 130. He states that the 
counter electro-motive force is thus dissipated in the re- 
sistance when the contact is broken, as the resistance thus 
becomes a sort of condenser, and almost entirely does away 



THE MODERN' CLOCK. 389 

with heating and burning of the contacts, while keeping the 
circuit open when the battery is doing no work. 

It has been suggested to the writer by several engineers 
of high attainments and large experience that what should 
be used in the above combination is a condenser in place of 
a resistance spool, as there would then be no expenditure of 
current except for work. One of the clocks changed to this 
system just before the failure of its manufacturers, but as 
less than four hundred clocks were made with the con- 
densers (Fig. 131), the point was not conclusively demon- 
strated. 

It should also be borne in mind that the condenser has 
been vastly improved within the last twelve months. With 
the condenser it will be observed that there is an abso- 
lutely open circuit while the armature is doing no work 
and that therefore the battery should last that much longer, 
Figs. 130 and 131. As to the cost of the condensers as 
compared with resistance spools, we are not informed, but 
imagine that with the batteries lasting so much longer and 
the clock consequently giving so much better satisfaction, 
a slight additional cost in manufacture by changing from 
resistance to condensers would be welcomed, if it added to 
the length of life and the surety of operation. 

Electric clocks cost more to make than spring or weight 
clocks and sell for a higher price and a few cents additional 
per movement would be a very small premium to pay for an 
increase in efficiency. 

The repairer who takes down and reassembles one of 
these clocks very often ignorantly makes a lot of trouble for 
himself. Many of the older clocks were built in such a way 
that the magnets could be shifted for adjustment, instead 
of being put in with steady pins to hold them accurately in 
place. The retail jeweler who repairs one of these clocks is 
apt to get them out of position in assembling. The arma- 
ture should come down squarely to the magnets, but should 
not be allowed to touch, as if the iron of the armature 



390 THE MODERN CLOCK. 

touches the poles of the magnet it will freeze and retain 
its magnetism after the current is broken. Some manufac- 
turers avoid this by plating their armatures with copper or 
brass and this has puzzled many retailers who found an 
electro-magnet apparently attracting a piece of metal which 
is generally understood to be non-magnetic. 

The method offers a good and permanent means of in- 
sulating the iron of the armature from the magnet poles 
while allowing their close contact and as the strength of a 
magnet increases in proportion to the square of the distance 
between the poles and the armature, it will be seen that 
allowing the armature to thus approach as closely as pos- 
sible to the poles greatly increases the pull of the magnet 
at its final point. If when setting them up the magnet and 
armature do not approach each other squarely, the armature 
will touch the poles on one side or another and soon wear 
through the copper or brass plating designed to maintain 
their separation and then we will have freezing with its 
accompanying troubles. 

A very good test to determine this is to place a piece of 
watch paper, cigarette paper or other thin tissue on the 
poles of the magnet before the naked iron armature is 
drawn, down. Then make the connection, hold the armature 
and see if the paper can be withdrawn. If it cannot the 
armature and poles are touching and means should be 
taken to separate them. This is sometimes done by driving 
a piece of brass into a hole drilled in the center of the pole 
of the magnet; or by soldering a thin foil of brass on the 
armature. As long as the separation is steadily maintained 
the object sought is accomplished, no matter what means 
is used to attain it. 

Another point with clocks which have their armatures 
moved in a circular direction is to see that the magnet is so 
placed as to give the least possible freedom betv^een the 
armatures and the circular poles of the magnet, but that 
there must be an air-gap between the armature and magnet 
poles. 



THE MODERN CLOCK. 39I 

In those clocks which wind a spring by means of a lever 
and ratchet working- into a fine-toothed ratchet wheel, or 
are driven by a weighted lever, there is an additional point 
to guard against. If the weight lever is thrown too far up, 
either one of two things will happen. The weight lever 
may be thrown up to ninety degrees and become balanced 
if the butting post is left off or wrongly replaced ; the 
power will then be taken off the clock, if it is driven directly 
by weight, so that a butting post should meet the lever at 
the highest point and insure that it will not go beyond this 
and thus lose the efficiency of the weight. 

In the cases where a spring on the center arbor is inter- 
posed between the arbor and the ratchet wheel, it should be 
determined just how many teeth are necessary to be oper- 
ated when winding, as if a clock is wound once an hour 
and the aim is to wind a complete turn (which is the amount 
the arbor has run down) if the lever is allowed to vibrate 
©ne or tw^o teeth beyond a complete turn, it will readily be 
seen that in the course of time the spring will wind itself 
so tightly as to break or become set. This was a frequent 
fault with the Dulaney clock and has not been guarded 
against sufficiently in some others which use the fine ratchet 
tooth for winding. 

When such a clock is found the proper number of teeth 
should be ascertained arid the rest of the mechanism ad- 
justed to see that just that number of teeth will be wound 
If less is wound there will come a time when the spring 
will run down and the clock will stop. If too much is 
wound the spring will eventually become set and the clock 
will stop. Therefore such movements should be examined 
to see that the proper amount of winding occurs at each 
operation. Of course where a spring is wound and there 
are but four notches in the ratchet wheel and the screw stop 
is accurately placed to stop the action of the armature, over 
action will not harm the spring, provided it will not go to 
another quarter, as if the armature carries the ratchet wheel 



39^ 



THE MODERN CLOCK. 



further than it should, the smooth circumference between 
the notches will let it drop back to its proper notch. 

There are a large number of clocks on the market which 
wind once per hour. These differ from the others in that 
they do not depend upon a single movement of the arma- 
ture for an instantaneous winding. Thus if the batteries 
are weak it may take twenty seconds to wind. If the bat- 
teries are strong and new it may wind in six seconds. In 
this respect the clock differs radically from the others, and 
while we have not personally had them under test, we are 
informed that on account of winding once per hour the 
batteries will last very much longer than would be expected 
proportionately from those which wind at periods of greater 
frequency. The reason assigned is that the longer period 
allows the battery to dispose of its hydrogen on the zinc 
and thus to regain its energy much more completely between 
the successive discharges and hence can give a more effect- 
ive quantity of current for hourly discharge than those 
which are discharged several times a minute, or even sev- 
eral times an hour. It is only proper to add that the manu- 
facturers of clocks winding every six or seven minutes 
dispute this assertion. 

Another point is undoubtedly in the increased length of 
life of the contacts; but speaking generally the electric 
clock may be said now to be waiting for further improve- 
ments in the batteries. Those who have had the greatest 
experience with batteries, as the telephone companies, tele- 
graph companies and other public service corporations, have 
generally discarded their use in favor of storage batteries 
and dynamos wherever possible and where this is not pos- 
sible they have inspected them continuously and regularly. 

In this respect one point will be found of great service. 
When putting in a new set of batteries in any electrical 
piece of machinery, write the date in pencil on the battery 
cover, so that you, or those who come after you, some time 
later, will know the exact length of time the battery has 



THE MODERN CLOCK. 393 

been in service. This is frequently of importance, as it 
will determine very largely whether the battery is playing 
out too soon, or whether faults are being charged to the 
battery which are really due to other portions of the ap- 
paratus. 

Never put together any piece of electrical apparatus with- 
out seeing that all parts are solidly in position and are 
clean ; always look carefully to connections and see that the 
insulation is perfect so that short circuits will be impossible. 

All contacts must be kept smooth and bright and contact 
must be made and broken without any wavering or uncer- 
tainty. 

Fig. 132 shows the completely wired movement of the 
American Clock Company's weight-driven movement, which 
may be accepted as a type of this class of movements — > 
weight-driven, winding every seven minutes. 

The train is a straight-line time train, from the center 
arbor to the dead beat escapement, with the webs of the 
wheels not crossed out. It is wired with the wire from the 
battery zinc screwed to the front plate H and that from 
the battery carbon to an insulated block G. 

Fig. 133 shows an enlarged view of the center arbor. 
Upon this arbor are secured (friction tight) two seven- 
notched steel ratchets, E, and carried loosely between them 
are two weighted levers pivoted loosely on the center arbor. 
Each lever is provided with a pawl engaging in the notches 
of the nearest ratchet, as shown. The weighted lever has 
a circular slot cut in it, concentric with the center hole and 
also has a portion of its circumference at the arbor cut 
away, thus forming a cam. Between these two levers is a 
connecting link D with a pin in its upper end, which pin 
projects into the circular slots of the weight levers. 

The lever F is pivoted to the front plate of the clock and 
carries at right angles a beveled arm which projects over 
the ratchets E, but is ordinarily prevented from dropping 
into the notches by riding on the circumferences of the 



394 



THE MODERN CLOCK. 




o O 

CO O CO 

oc 2 of 

2 N CONNECTING WIRE S 



jH ^rM ggw riHi'^ 



Fig. 132 



THE MODERN CLOCK. 



395 



weighted levers. When one lever has dropped down and 
the other has reached a horizontal position the cut portions 
of the circumferences of these levers will be opposite the 
upper notch of the ratchets and will allow the bar project- 




Fig. 133 



ing from F to drop into the notches. This allows F and G 
to connect and the magnet A is energized, pulls the arma- 
ture B, the arms C D, and thus lifts the lever through the 
pin in D pulling at the end of the circular slot. As the 
lever flies upward, the cam-shaped portion of its circum- 



39^ 



THE MODERN CLOCK. 



ference raises the arm out of the notches, thus separating 
F and G and breaking the circuit. A spring placed above 
E keeps its arms pressed constantly upon E in position to 
drop. The wiring of the magnets is shown in Fig. 130. 

The upper contact (carried in F) is a piece of platinum 
with its lower edge cut at an angle of fifteen degrees and 
beveled to a knife-edge. The lower point of this bevel 
comes into contact first and is the last to separate when 
breaking connection, so that any sparking which may take 
place will be confined to one edge of the contacts while the 
rest of the surface remains clean. (See Fig. 134.) Ordi- 



^^ 




Fig. 134 

narily there is very little corrosion from burning and this is 
constantly rubbed off by the sliding of the surfaces upon 
each other. The lower contact, G, consists of a brass block 
mounted upon an insulating plate of hard rubber. The 
block is in two pieces, screwed together, and each piece 
carries a platinum tipped steel spring. These springs are 
so set as to press their platinum tips against each other di- 
rectly beneath the upper contact. The upper and lower 
platinum tips engage each other about one-sixteenth inch at 
the time of making contact. The lower block being in two 
pieces, the springs may be taken apart for cleaning, or to 
adjust their tension. The latter should be slight and should 



THE MODERN CLOCK. 397 

in no case exceed that which is exerted by the spring in 
F, or the upper knife-edge will not be forced between the 
two lower springs. The pin on which F is pivoted and that 
bearing on the spring above it must be clean and bright and 
never he oiled, as it is through these that the current passes 
to the upper contact in the end of F. The contacts are, of 
course, never oiled. 

The two weighted levers should be perfectly free on the 
center arbor and their supporting pawls should be perfectly 
free on the shoulder screws in the levers. Their springs 
should be strong enough to secure quick action of the 
pawls. This freedom and speed of action are important, 
as the levers are thrown upward very quickly and may re- 
bound from the butting post without engaging the ratchets 
if the pawls do not work quickly. 

The projecting arm, C, of the armature, B, has pivoted 
to it, a link, D, which projects upward and supports at its 
upper end a cross pin. The link should not be tight in the 
slot of C, but should fit closely on the sides, in order to 
keep the cross pin at the top of D parallel with the center 
staff of the clock. This cross pin projects through D an 
equal distance on either side, each end respectively passing 
through the slot of the corresponding lever, the total length 
of this pin being nearly equal to the distance between the 
ratchets. When the electric circuit is closed, and the mag- 
nets energized, B, C and D are drawn downward; the 
weighted end of one of the levers which runs the clock, 
being at this time at the limit of its downward movement, 
see Fig. 135, the opposite or slotted end of said lever, is 
then at its highest point, and the downward pull in the 
slot by one end of the above described crosspin which en- 
ters it will throw the weighted end of the said lever upward. 
The direct action" of the magnets raises the lever nearly to 
the horizontal position, and the momentum acquired carries 
it the remainder of the distance. By this arrangement of 
stopping the downward pull of the pin when the ascending 



398 



THE MODERN CLOCK. 



lever reaches the horizontal, all danger of disturbing the 
other lever A is avoided. The position is such that the top 
of the ascending lever weight is about even with the center 
of the other weight when the direct pull ceases. 




Fig. 135 



Before starting the clock raise the lever weights so that 
one lever is acting upon a higher notch of the ratchet than 
the other. They are designed to remain about forty-five 
degrees apart, so as to raise only one lever at each action of 
the magnet. This maintains an equal weight on the train, 
which would not be the case if they were allowed to rise 
and fall together ; keeping the levers separated also reduces 
the amount of lift or pull on the battefy and uses less cur- 



THE MODERN CLOCK. 399 

rent, which Is an item when the battery is nearly run down. 
If these levers are found together it indicates that the bat- 
tery is weak, the contacts dirty, making irregular winding, 
or the pawls are working improperly. See that the levers 
rise promptly and with sufficient force. After one of them 
has risen stop the pendulum and see that the butting post 
is correctly placed, so that there is no danger of the lever 
wedging under the post and sticking there, or causing the 
lever to rebound too much. The butting post is set right 
when the clock leaves the factory and seldom needs adjust- 
ment unless some one has tinkered with it. 

The time train should be oiled as with the ordinary move- 
ments, also the pawls on the levers. The lever bushings 
should be cleaned before oiling and then well oiled in order 
to avoid friction on the center arbor from the downward 
pull of the magnets when raising the levers. In order to 
clean the levers drive out the taper pin in the center arbor 
and remove the front ratchet, when the levers will slip off. 
In putting them back care should be used to see that the 
notches of the ratchets are opposite each other. Oil the 
edges of the ratchets and the armature pins. Do not under 
any circumstances oil the contact points, the pins or springs 
of the bar F, as this will destroy the path of the current 
and thus stop the clock. These pins must be kept clean 
and bright. 

Hourly Winding Clocks. — There are probably more of 
these in America than of all other electric kinds put to- 
gether (we believe the present figures are something like 
135,000), so that it will not be unreasonable to give consid- 
erable space to this variety of clocks. Practically all of 
them ar€ made by the Self Winding Clock Company and 
are connected with the Western Union wires, being wound 
by independent batteries in or near the clock cases. 

Three patterns of these clocks have been made and we 
will describe all three. As they are all practically in the 



400 THE MODERN CLOCK. 

same system, it will probably be better to first make a 
simple statement of the wiring, which is rigidly adhered to 
by the clock company in putting out these goods. All wires 
running from the battery to the winding magnets of the 
movement are brown. All wires running from the syn- 
chronizing magnet to the synchronizing line are blue. Mas- 
ter clocks and sub-master clocks have white wires for re- 
ceiving the Washington signal and the relay for closing the 
synchronizing line will, have wires of blue and white plaid. 




Fig. 136 

By remembering this system it is comparatively easy for 
a man to know what he is doing with the wires, either 
inside or outside of the case. For calendar clocks there are, 
in addition, two white wires running from the calendar to 
the extra cell of battery. There is also one other peculiar- 
ity, in that these clocks are arranged to be wound by hand 
whenever run down (or when starting up) by closing a 
switch key, shown in Fig. 136, screwed to the inside of the 
case. This is practically an open switch, held open by the 
spring in the brass plate, except when it is pressed down to 
the lower button. 

The earliest movement of which any considerable number 
were sent out was that of the rotary winding from a three- 
pole motor, as shown in Fig. 137. Each of these magnet 
spools is of two ohms, with twelve ohms resistance, placed 
in parallel with the winding of each set of magnet spools, 
thus making a total of nine spools for the three-pole 
motor. 

On the front end of the armature drum arbor is a com- 
mutator having six points, corresponding to the six arma- 



THE MODERN CLOCK, 



401 




Fig. 137 



402 THE MODERN CLOCK. 

tures in the drum. There are three magnets marked O, 
P and X; each magnet has its own brush marked O', P' 
and X'. When an armature approaches a magnet (see Fig. 
137) the brush makes contact with a point of the com- 
mutator, and remains in contact until the magnet has done 
its work and the next magnet has come into action. When 
properly adjusted the brush O' will make contact when 
armatures i and 2 are in the position shown, with No. 2 a 
little nearer the core of the magnet than No. i ; and it will 
break contact when the armature has advanced into the 
position shown by armature No. 3, the front edge of the 
armature being about one-sixteenth of an inch from the 
corner of the core, armature No. 4 . being entirely out of 
circuit, as brush X' is not touching the commutator. 

The back stop spring, S, Fig. 137, must be adjusted so 
that the brush O' is in full contact with a point of the 
commutator when the motor is at rest, with a tooth of the 
ratch touching the end of the spring, S. 

Sometimes the back stop spring, S, becomes broken or 
bent. When this occurs it is usually from overwinding. It 
must be repaired by a new spring, or by straightening the 
old one by burnishing with a screwdriver. Set the spring 
so that it will catch about half way dotvn the last tooth. 

Having explained the action of the motor we come now 
to the means of temporarily closing the circuit and keeping 
it closed until such time as the spring is wound a suffi- 
cient amount to run the clock for one hour; as the spring 
is on the center arbor this requires one complete turn. 

This is the distinguishing feature of this system of clocks 
and is not possessed by any of the others. It varies in con- 
struction in the various movements, but in all its forms it 
maintains the essential properties of holding the current on 
to the circuit until such time as the spring has been wound 
a sufficient quantity, when it is again forcibly broken by the 
action of the clock. This is termed the "knock away," and 
exists in all of these movements. 



THE MODERN CLOCK. 403 

To start the motor the circuit is closed by a platinum 
tipped arm, A, Fig. 138, loosely mounted on the center 
arbor, and carried around by a pin projecting from the 
center wheel until the arm is upright, when it makes con- 
tact with the insulated platinum tipped brush, B. A carries 
in its front an ivory piece which projects a trifle above the 
platinum top, so that when B drops off the ivory it will 
make contact with the platinum on A firmly and suddenly. 
This contact then remains closed until the spring barrel is 
turned a full revolution, when a pin in the barrel cover 
brings up the "knock away," C, which moves the arm. A, 
forward from under the brush, B, and breaks the circuit. 
The brush, B, should He firmly on its banking piece, and 
should be so adjusted that when it leaves the arm. A, it will 
drop about one-thirty-second of an inch. Adjusted in this 
way it insures a good, firm contact. 

The angle at the top of the brush, B, must not be too 
abrupt, so as to retard the action of the clock while the 
contact is being made. Wire No. 8 connects the spring 
contact, B, to one of the binding plates at the left-hand 
side of the case ; and wire No. 6 connects the motor, M, to 
the other. To these binding plates are attached brown 
wires that lead one to each end of the battery. 

When the clock is quite run down, it is wound by press- 
ing the switch key, Fig. 136, from which a wire runs to the 
plate. The switch key should not be permanently connected 
to its contact screw, J. See that all wires are in good con- 
dition and all connections tight and bright. The main 
spring is wound by a pinion on the armature drum arbor, 
through an intermediate wheel and pinion to the wheel 
on the spring barrel. 

At stated times — say once in eighteen months or two 
years — all clocks should be thoroughly cleaned and oiled, 
and at the same time inspected to be sure they are in good 
order. 



404 



THE MODERN CLOCK. 



Never let the self-winding clocks run down backward, 
as the arm, A, Fig. 138, will be carried back against the 
brush, B, and bend it out of adjustment. 




Fig. 138 



To clean the movement, take it from the case, take out 
the anchor and allow it to run down gently, so as not to 
break the piiis^ then remove the motor. Take ofif the 
front plate and separate all the parts. Never take off the 
back plate in these clocks. Wash the plates and all parts in 
a good quality of benzine, pegging out the holes and let- 
ting them dry thoroughly before reassembling. The motor 
must not be taken apart, but may be washed in benzine, 
by using a small brush freely about the bearings, com- 



THE MODERN CLOCK. 4O5 

mutator and brushes. Put oil in all the pivot holes, but not 
so much that it will run. The motor bearings and the pal- 
lets of the anchor should also be oiled. 

Inspect carefully to see that the center winding con- 
tact is right and that the motor is without any dead points. 
Dust out. the case and put the movement in place. Before 
putting on the dial try the winding by means of the switch, 
Fig. 136, to be sure that it is right; also see that the disc 
on the cannon socket is in the right position to open the 
latch at the hour, and after the dial and hands are on move 
the minute hand forward past the hour and then backward 
gently until it is stopped by the latch. This will prove 
that the hand is on the square correctly. 

On account of the liability of the motor to get out of 
adjustment and fail to wind, from the shifting of the 
springs and brushes, under careless adjustment, various at- 
tempts have been made to improve this feature of these 
clocks and the company is now putting out nearly alto- 
gether one of the two vibrating motors, shown in Figs. 
139 and 140. 

In Style C, Fig. 139, the hourly contact for winding is the 
same as in the clock with the three-magnet motor, as shown 
in Fig. 138. The magnet spools are twelve ohms and the 
resistance coil is eighty ohms, placed in parallel, as de- 
scribed in Fig. 130. 

The vibrating motor, Fig. 139, is made with a pair of 
magnets and a vibrating armature. The main spring is 
wound by the forward and backward motion of the arma- 
ture, one end of the connecting rod, 8, being attached 
to a lug of the armature, 2, and the other to the winding 
lever, 10. This lever has spring ends, to avoid shock and 
noise. As the winding lever is moved up and down, the 
pawl, 9, turns the ratch wheel, 11, and a pinion on the 
ratch wheel arbor turns the spring barrel until the winding 
is completed. 



4o6 



THE MODERN CLOCK. 




Fig. 139 



THE MODERN CI>OCK, 407 

The contact for operating the motor is made by the brass 
spiral spring, 3, which is attached to the insulated stud, 4, 
and the platinum pin, 5, which is carried on a spring at- 
tached to the clock plate. As the armature moves forward 
the break pin, A, in the end of the armature lifts the con- 
tact spring, 3, thus breaking the circuit. The acquired mo- 
mentum carries the armature forward until it strikes the 
upper banking spring, 6, when it returns rapidly to its 
original position, banking on spring 7, by which time con- 
tact is again made between springs 3 and 5 and the vibra- 
tion is repeated until the clock is wound one turn of the 
barrel and the circuit is broken at the center winding 
contact. 

Fig. 140, Style F, is a similar motor so far as the vibrat- 
ing armature and the winding is concerned, but the wind- 
ing lever is pivoted directly on the arbor of the winding 
wheel and operates vertically from an arm and stud on the 
armature shaft, working in a fork of the winding lever, 8, 
Fig. 140. It will be seen that the train and the motor 
winding mechanism are combined in one set of plates. The 
motor is of the oscillating type and its construction is such 
that all its parts may be removed without dissembling the 
iclock train. 

Construction of the Motor. — The construction of the 
motor is very simple, having only one pair of magnets, but 
two sets of make and break contacts, one set of which is 
placed on the front and the other on the back plate of the 
movement, thus ensuring a more reliable operation of the 
motor, and reducing by fifty per cent the possibility of its 
failing to wind. 

The center winding contact also differs from those used 
in the three-magnet motors and former styles of vibrating 
motor movements. The center winding contact piece, 13, 
has no ivory and no platinum. The hourly circuit is not 
closed by the current passing through this piece, but it acts 



4o8 



THE MODERN CLOCK. 



by bringing the plate contact spring, i6, in metallic connec- 
tion with the insulated center-winding contact spring, .17, 
both of which are platinum tipped. It will thus be seen 
that no accumulation of dirt, oil or gum around the center 
arbor or the train pivots will have any effect in preventing 
the current from passing from the motor to the hourly cir- 
cuit closer. 




Fis. 140 



The operation is as follows : As the train revolves, the 
pin, 12, securely fastened to the center arbor, in its hourly 
revolution engages a pin on the center winding contact 
piece, 13. This piece as it revolves pushes the plate con- 
tact spring, 16, upward, bringing it in metallic connection 
with the center winding contact spring, 17, which is 
fastened to a stud on an insulated binding post, 18, thereby, 
closing the hourly circuit. The current passes from the 
binding post, 18, through the battery (or any other source 
of current supply) to binding post 19, to which is connect- 



THE MODERN CLOCK. 409 

ed one end of the motor magnet wire. The current passes 
through these magnets to the insulated stud, 4. To this 
stud the spiral contact spring, 3, is fastened and the cur- 
rent passes from this spring to the plate contact spring, 5, 
thence through the movement plate to plate contact spring, 
16, and from there through spring, 17, back to the battery. 

The main spring is wound by the forward and backward 
motion of the armature, 2. To this armature is connected 
the winding lever, 8. As the winding lever is oscillated, the 
pawl, 9, turns the ratchet wheel, 11, and a pinion on the 
ratchet wheel arbor turns the winding wheel until the pin, 
15, connected to it engages the knock-away piece, 14, re- 
volving it until it strikes- the pin on the center winding 
contact piece, 13, and pushes it from under the plate contact 
spring, thereby breaking the electric circuit and completing 
the hourly winding. 

The proper position of the contact springs is clearly indi- 
cated in Fig. 140. The spring, 16, should always assume 
the position shown thereon. When the center winding 
contact piece, 13, comes in metallic connection with the 
plate contact spring, 16, the end of this spring should 
stand about one-thirty-second of an inch from the edge 
of the incline. The center winding contact spring, 17, 
should always clear the plate contact spring one-thirty- 
second of an inch. When the two springs touch they 
should be perfectly parallel to each other. 

Adjustments of the Armature. — In styles C and F, 
when the armature, 2, rests on the banking spring, 7, its 
front edge should be in line with the edge of the magnet 
core. The upper banking spring, 6, must be adjusted so 
that the front edge of the armature will be one-sixteenth of 
an inch from the corner of the magnet core when it touches 
the spring. 

When the contact spring, 3, rests on the platinum pin, 5, 
it should point to about the center of the magnet core, with 



4IO THE MODERN CLOCK. 

the platinum pin at the middle of the platinum piece on the 
spring. 

To adjust the tension of the spiral contact spring, 3, take 
hold of the point with a light pair of tweezers and pull it 
gently forward, letting it drop under the pin. It should 
take the position shown by the dotted line, the top of the 
spring being about one-thirty-second of an inch below the 
platinum pin. If from any cause it has been put out of ad- 
justment it can be corrected by carefully bending under the 
tweezers, or the nut, 4, may be loosened and the spring 
removed. It may then be bent in its proper shape and 
replaced. 

The hole in the brass hub to which the spring is fastened 
has a flat side to it, fitting a flat on the insulated contact 
stud. If the contact spring is bent to the right position it 
may be taken off and put back at any time without chang- 
ing the adjustment, or a defective spring may readily be 
replaced with a new one. When the armature touches the 
upper banking spring the spiral contact spring, 3, should 
clear the platinum pin, 5, about one-sixteenth of an inch. 
Both contacts on front and back plates in style F are ad- 
justed alike. The circuit break pins "A" on the armature 
should raise both spiral contact sprmgs at the same instant. 

If for any reason the motor magnets have become dis- 
placed they may readily be readjusted by loosening the 
four yoke screws holding them to the movement plates. 
Hold the armature against the upper banking spring, move 
the magnets forward in the elongated slot, 20, until the 
ends of the magnet cores clear the armature by one-sixty- 
fourth of an inch, then tighten down the four yoke screws. 
Connect the motor to the battery and see that the arma- 
ture has a steady vibration and does not touch the magnet 
core. The adjustment should be such that the armature 
can swing past the magnet core one-eighth to three-six- 
teenths of an inch. 



THE MODERN CI.OCK. 4II 

Description of Synchronizer. — At predetermined 
times a current is sent through the synchronizer magnet, 
D', Fig. 141, which actuates the armature, E, to which arc 
attached the levers, F and G, moving them down until tlic 
points on the lever, G, engage with two projections, 4 and 
5, on the minute disc; and lever F engages with the 
heart-shaped cam or roll on the seconds arbor sleeve, 
causing both the minute and second hands to point to XII. 
These magnet spools are wound to twelve ohms, w^ith an 
eighty-ohm resistance in parallel. 

On the latch, L, is a pin, I, arranged to drop under the 
hook, H," and prevent any action of the synchronizing 
levers, except at the hour. A pin in the disc on the can- 
non socket unlocks the latch about two minutes before the 
hour and closes it again about two minutes after the signal. 
This is to prevent any accidental ''cross" on the synchron- 
izing line from disturbing the hands during the hour. 

AI is a Hght spring attached to the synchronizing frame 
to help start the armature back after the hands are set. 
The wires from the synchronizing magnet are connected to 
binding plates at the right-hand side of the clock and from 
these binding plates the blue wires, Nos. 9 and 10, pass out 
at the top of the case to the synchronizing line. 

If the clock gets out of the synchronizing range it gen- 
erally indicates very careless regulation. The clock is regu- 
lated by the pendulum, as in all others, but there is one 
peculiarity in that the pendulum regulating nut has a 
check nut. 

If the clock gains time turn the large regulating nut 
under the pendulum bob slightly to the left. 

If the clock loses time turn the nut slightly to the 
right. 

Loosen the small check nut under the regulating nut 
before turning the regulating nut, and be sure to tighten 
the check nut after moving the regulating nut. 



412 



THE MODERN CLOCK. 




Fig. 141 



THE MODERN CLOCK. 413 

The friction of the seconds hand is very carefully ad- 
justed at the factory, being weighed by hanging a small 
standard weight on the point of the hand. If it becomes 
too light and the hand drives or slips backward, losing 
time, it can be made stronger by laying it on a piece of 
wood and rubbing the inner sides of the points with a 
smooth screw driver, and if too heavy and the clock will 
not set when the synchronizing magnets are actuated, the 
points of the spring in the friction may be straightened a 
little. 

If the seconds hand sleeve does not hold on the seconds 
socket, pinch it a little with pliers. If the seconds hand is 
loose on the sleeve put on a new one or solder it on the 
under side. 

In style F the synchronizing lever, heart-shaped sec- 
onds socket and cams on the cannon sockets are the same 
as in the old style movements, shown in Fig. 141. The 
difference is in the synchronizing magnets and the way 
they operate the synchronizing lever. The magnet has 
a flat ended core instead of being eccentric like the former 
ones. The armature is also made of flat iron and is pivoted 
to a stud fastened to the synchronizing frame. The arma- 
ture is connected to the synchronizing lever by a connect- 
ing rod and pitman screws. A sector has an oblong slot, 
allowing the armature to be lowered or raised one-six- 
teenth of an inch. The synchronizing lever is placed on a 
steel stud fastened to the front plate and held in position 
by a brass nut. The synchronizing magnets are 12 ohms 
with 80 ohms resistance and are fastened to a yoke which 
is screwed to the synchronizing frame by four iron screws. 
The holes in the synchronizing frame are made oblong, 
allowing the yoke and magnets to be raised or lowered one- 
sixteenth of an inch. The spring on top of the armature 
is used to throw it back quickly and also acts as a diamag- 
netic, preventing the armature from freezing to the mag- 
nets. A screw in the stud is used to screw up against the 



414 THE MODERN CLOCK. 

magnet head, preventing any spring that might take place 
on the armature stud. Binding posts are screwed to the 
synchronizing frame and the ends of the magnet coils are 
fastened thereto with metal clips. 

The blue wires in the clock case are coiled and have a 
metal clip soldered to them.* They connect direct by these 
clips to the binding posts, thus making a firm connection, 
and are not liable to oxidize. With the various points of 
adjustment a pair of magnets burned out or otherwise 
defective may readily be replaced in from five to ten min- 
utes. 

When replacing a pair of synchronizing magnets pro- 
ceed as follows : Remove the old pair and then loosen all 
four screws in the yoke, pushing it up against the tops 
of the oblong holes, then tighten down lightly. Fasten the 
new pair of magnets to the yoke with the inner ends of 
the coils showing at the outside of the movement. Press 
the armature upward until the synchronizing lever locks 
tightly on the cannon socket and the heart-shaped cams, 
then loosen the magnet yoke screws and press the magnets 
down on the spring on top of the armature. Then tighten 
the yoke screws on the front plate and see that the back 
of the magnets clears the armature by one-hundredth of 
an inch (the thickness of a watch paper), when the screws 
in the back of the yoke can be set down firmly. The ad- 
justment screw may then be turned up until it presses 
lightly against the magnet head. When current is passed 
through the magnets and held there the armature must 
clear the magnets without touching. The magnet coils 
must then be connected to their respective binding posts by 
slipping the metal clips soldered to them under the rubber 
bushing, making a metallic connection with the binding 
plates. Fasten these screws down tight to insure good 
connections. 



THE MODERN CLOCK, 



415 



The Master Clock. — Is a finely finished movement 
with mercurial pendulum that beats seconds and a Gerry 
gravity escapement. At the left and near the center of the 
movement is a device for closing the synchronizing circuit 



/O^ 




Fig. U2 



once each hour. The device consists of a stud on which 
is an insulator having two insulated spring fingers, C and 
D, one above the other, as shown in Fig. 142, except at 
the points where they are cut away to lie side by side on 
an insulated support. On these fingers, and near the 
insulator, are two platinum pieces, E and F, so adjusted 



4l6 THE MODERN CLOCK. 

as to be held apart, except at the time of synchronizing. 

A projection, B, from the insulator rests on the edge 
of -a disc on the center arbor. At ten seconds before the 
hour, a notch in this disc allows the spring to draw the 
support downward, leaving the points of the fingers, C 
and D, resting on the raised part of the rubber cam on 
the escape arbor. The end of the finger, C, is made 
shorter than that of D, and at the fifty-ninth second, C 
drops and closes the circuit by E striking F. At the 
next beat of the pendulum the long finger D drops and 
opens the circuit again. 

The winding is the same as in the regular self-winding 
clocks, the motor wire and seconds contact being con- 
nected to the binding plates at the left, from which 
brown wires lead up to the battery. Two wires from the 
synchronizing device are connected to the binding plates 
at the left, from which blue wires run out to the line. 

Before connecting the clock to the line it must be run 
until it is well regulated, and also to learn if the con- 
tacts are working correctly. Regulate at first by the 
nut at the bottom of the rod until it runs about one 
second slow in 24 hours (a full turn of the nut will 
change the rate about one-half miniite per day). The 
manufacturers send with each clock a set of auxiliary 
pendulum weights, the largest weighing one gram, the 
next in size five decigrams and the smallest two deci- 
grams; these weights are to make the fine regulations by 
placing one or more of them on the little table that is 
fastened about the middle of the pendulum rod. The five 
decigram weight will make the clock gain about one 
second per da}^, and the other weights in proportion. 
Care must be taken not to disturb the swing of the 
pendulum, as a change of the arc changes the rate. 

To start the clock after it is regulated, stop it, with 
the second hand on the fiftieth second; move the hands 
forward to the hour at which the signal comes from the 



THE MODERN CLOCK. 



^'7 



observatory; then press the minute hand back gently un- 
til it is stopped by the extension on the hour contact, 
Fig. 142, and beat the clock up to the hour. This ensures 
the hour contact being in position to send the synchronize 
ing signal. 

A good way to start it with observatory time is with 
all the hands pointing to the "signal" hour; hold the 
pendulum to one side and when the signal comes let it 
go. With a little practice it can be started very nearly 
correct. 

Clocks not lettered in the bottom of the case must be 
wound before starting the pendulum. To do this press 
the switch shown in Fig. 136, which is on the left side 
of the case and under the dial. 

Continue the pressure until the winding ceases. Then 
set the hands and start the pendulum in the usual way. 
If the bell is not wanted to ring, bend back the hammer. 

Secondary Dials. — One of the most deceptive branches 
of clock work is the secondary dial, or "minute jumper." 
Ten years ago it was the rule for all manufacturers of elec- 
tric clocks to put out one or more patterns of secondary 
dials. Theoretically it was a perfect scheme, as the sec- 
ondary dial needed no train, could be cheaply installed and 
could be operated without trouble from a master clock, so 
that all dials would show exactly the same time. Practical- 
ly, however, it proved a very deceptive arrangement. The 
clocks were subject to two classes of error. One was that it 
was extremely difficult to make any mechanical arrangement 
in which the hands would not drive too far or slip backward 
when the mechanism was released to advance the minute 
hand. The second class of errors arose from faulty con- 
tacts at the master clock and variation in either quantity 
or strength of current. Another and probably the worst 
feature was that all such classes of apparatus record their 
own errors and thereby themselves provide the strongest 



4lS THE MODERN CLOCK. 

evidence for condemnation of the system. Clocks could be 
wound once an hour with one-sixtieth of the chance of error 
of those wound once per minute, and they could be wound 
hourly and synchronized daily with i-i440th of the line 
troubles of a minute s}^stem. 

The minute jumpers could not be synchronized without 
costing as much to build and install as an ordinary self- 
winding clock, with pendulum and time train, and after try- 
ing them for about ten years nearly all the companies have 
substituted self-winding time train clocks with a synchron- 
izing system. They have apparently concluded that, since 
it seems too much to expect of time apparatus that it will 
work perfectly under all conditions, the next thing to do is 
to make the individual units run as close to time as is com- 
mercially practicable and then correct the errors of those 
units cheaply and quickly from a central point. 

It is for these reasons that the secondary dial has prac- 
tically disappeared from service, although it was at one time 
in extensive use by such companies as the Western Union 
Telegraph Company, the Postal Telegraph and the large 
buildings in which extensive clock systems have been in- 
stalled. 

Fig. 143 shows one form of secondary dial which in- 
volves a screw and a worm gear on the center arbor, which, 
it will be seen, is adapted to be turned through one minute 
intervals without the center arbor ever being released from 
its mechanism. This worm gear was described in the 
American Jeweler about fifteen years ago, when patented 
by the Standard Electric Time Company in connection with 
their motor-driven tower clocks, and modifications of it have 
been used at various times by other companies. 

The worm gear and screw system shown in Fig. 143 has 
the further advantage that it is suitable for large dials, as 
the screw may be run in a box of oil for dials above four 
feet and for tower clocks and outside work. This will read- 
ily be seen to be an important advantage in the case of large 



THE MODERN CLOCK. 



419 



hands when they arc loaded with snow and ice, requiring- 
more power to operate them. 

All secondaries operate by means of an electromagnet 
raising a weight, the weight generally forming the armature ; 
the fall of the weight then operates the hands by gravity. 




Fig.143. Minute jumper. A, armature; M, magnets; "W, worm gear on 
center arbor ; B, oil box for worm ; R, four toothed ratchet. 



Direct action of the current in such cases is impracticable, 
as the speed of starting with an electric current would 
cause the machine to tear itself to pieces. 

This screw gear is the only combination known to us that 
will prevent the hands from slipping or driving by and re- 
duces the errors of the secondary system to those of one 
class, namely, imperfections in the contact of the master 
clock, insufficient quantity or strength of current, or acci- 
dental "crosses" and burnings. 

The series arrangement of wiring secondaries was for- 
merly greatly favored by all of the manufacturers, but it 



420 



THE MODERN CLOCK. 



was found that if anything happened to one clock it stopped 
the lot of them; and where more than fifty were in series, 
the necessary voltage became so high that it was impractica- 
ble to run the clocks with minute contacts. The modern 
system, therefore, is to arrange them in multiples, very much 
after the fashion of incandescent lamps, then if one clock 
goes wrong the others are not affected. Or if the current 
is insufficient to operate all, only those which are farthest 
away would go out of time. 

Very much smaller electromagnets will do the work than 
are generally used for it, and the economy of current in 
such cases is worth looking after, as with sixty contacts per 
"hour batteries rapidly play out if the current used is at all 
excessive. Where dry batteries are used on secondaries 
care should be taken to get those which are designed for gas 
engine ignition or other heavy work. Wet batteries, with 
the zincs well amalgamated, will give much better satisfac- 
tion as a rule and if thp plant is at all large it should be oper- 
ated from storage cells with an engineer to look after the 
battery and keep it charged, unless current can be taken 
from a continuously charged lighting main. This can be 
readily done in such instances as the specifications call for in 
the new custom house in New York, namely, one master 
clock and i6o secondary dials. 

Electric Chimes. — There have lately come into the mar- 
ket several devices for obtaining chimes which allow the 
separation of the chimes and the timekeeping apparatus, 
connection being made by means of electricity. In many 
respects this is a popular device. It allows, for instance, a 
full set of powerful tubular chimes, six feet or more in 
length, to be placed in front of a jewelry store, where they 
offer a constant advertisement, not only of the store itself, 
but of the fact that chiming clocks may be obtained there. 
It also allows of the completion by striking of a street clock 
which is furnished with a time train and serves at once as 



THE MODE KM CLOCK. 



421 



timepiece and sign. ]\lany of these have tubular chimes in 
which the hour bell is six feet in length and the others cor- 
respondingly smaller. They have also been made with bells 
of the usual shape, which are grouped on posts, or hung in 




Fig. 144. Cbimes of beUs in rack. 




Fig. 145. Chimes of bells with resonators. 



racks and operated electrically. It may also be used as a 
ship's bell outfit by making a few minor changes in the con- 
troller. 

Fig. 144 shows a peal of bells in which the rack is thirty- 
six inches long and the height of the largest bell is eight 
inches, and the total weight thirty pounds. This, as will 
readily be seen, can be placed above a doorway or any other 
convenient position for operation ; or it may be enclosed in 
a lattice on the roof, if the building is not over two stories 
in height. The lattice work will protect the bells from the 
weather and at the same time let out the sound. 

Fig. 145 shows the same apparatus with resonators at- 
tached. These are hollow tubes which serve as sounding 
boards, largely increasing the sound and giving the effect 



422 



THE MODERN CLOCK. 



of much larger bells. Fig. 146 shows a tubular chime and 
the electrical connections from the clock to the controller 
and to the hammers, which are operated by electro-magnets, 
so that a heavy leaden hammer strikes a solid blow at the 
tops of the tubes. 



^.^^'i!=^:;^^^^^^^;x3^ ^^ 



THF.W.GR£ENELEaRlcCQ^ 

"IMPERIAL" 

WuTMINSTERflETRICCHIflETIIBB 



U 



rr"--"i 



u 



Hi 

I 

i 



CkECTKIC J 
CONTROLLER 








y?^^ 



Fig. 146, Tubular electric chimes. 



The dials of such clocks contain electrical connections and 
the minute hand carries a brush at its outer end. The con- 
tact is shown in enlarged view in Fig. 147, by which it will 
be seen that the metal is insulated from the dial by means 
of hard rubber or other insulating material, so that the 
brush on the minute hand wall drop suddenly and firmly 
from the insulator to the metallic contact when the minute 
hand reaches fifteen, thirty, forty-five or sixty minutes. 
There is a common return wire, either screwed to the frame 
of the clock, or attached to the dial, which serves to close 



THE MODERN CLOCK. 423 

the various circuits and to give four strokes of the chimes at 
the quarter, eight at the half, twelve at the three-quarter, 
and sixteen at the hour, followed by the hour strike. The" 
friction on the center arbor is of course adjusted so as to 
carry the minute hand without slipping at the contacts. 

By this means a full chime clock may be had at much less 
cost than if the whole apparatus had to be self-contained and 
the facilities of separation between the chimes and the time- 
keeping apparatus, as hinted above, gives many advantages. 








Fig. 147. Enlarged view of connections on dial. 

For instance, the same clock and controller may operate 
tubes inside the room and bells outside, or vice versa. These 
are operated by wet or dry batteries purchased at local 
electrical supply houses, and the wiring is done with plain 
covered bell wire, or they may be operated by current from 
a lighting circuit, suitably reduced, if the current is con- 
stantly on the mains. As a full chime with sixteen notes 
at the hour strikes more than a thousand times a day, con- 
siderable care should be taken to obtain only the best bat- 
teries where these are used, as after the public gets used 
to the chimes the dealer will be gre:itly annoyed by the 
number of people asking for them if they are stopped tem- 
porarily. 

There has lately developed a tendency to avoid tlic set 
tunes, such as the Westminster and the Wliittington chimes, 
and to sound the notes as complete full notes, such as the 
first, third and fifth of the octave for the first, second and 
third quarters, followed by the hour strike. This allows 



424 THE MODERN CLOCK. 

them to be struck in any order and for a smaller chime re- 
duces the cost considerably. The tubes used are rolled of 
bell metal and vary in pitch with the manufacture,- so that 
the only way to obtain satisfactory tones is to cut your tubes 
a little long and then tune them by cutting ofif afterwards, 



/6 C/fimes ar7c/y,^^f^^^^ ^^^^^^^^anJ Connect/nn 
/}Oc/r ^^^^^^/^^^^^\^ *^0 1 II #^^>VA^;'^/W around 

/^^\ All / ^^'' ^/^/ 



Fig. 148. Connections and contacts on front of clock dial. 

the tone depending upon the thickness of. the wall' of the 
tube and its length. The bells are tuned by turning from 
the rim or from the upper portions as it is desired to raise 
or lower the tone, and if the resonators are used they are 
tuned in unison with the bells. 

Of the ordinary bells, Fig. 144, the dimensions run: 
First, height four inches, diameter ^Yi ; second, height four 
inches, diameter 5J4 inches ; third, height 4^ inches, diam- 
eter 5^ inches; fourth, height 4j/^ inches, diameter 5^ 
inches; fifth, height 4^ inches, diameter 63^ inches. For 



THE MODERN CLOCK. 



425 



the tubes the approximate length is six feet for the longest 
tube and the total weight of the chimes is 43 pounds. 
For the controller the size is nine by eleven by six inches, 



I 



1 
I 






I I I I 

® ® (9) ^ 







■//7<su/ofed 

9- 



Fig. 149. Connections and wiring on back of clock dial. 



with a weight of ten pounds. The hour strike may be had 
separately from the chimes if desired. 

This makes an easily divisible system and one that is be- 
coming very popular with retail jewelers and to some ex- 
tent with their customers. 



CHAPTER XXII. 

THE CONSTRUCTION AND REPAIR OF DIALS. 

Probably no portion of the clock is more important than 
the dial and it is apparently for this reason that we find so 
little variation in the marking. The public refuses to ac- 
cept anything in the way of ornamentation which interferes 
with legibility and about all that may be attempted is a lit- 
tle flat ornament in light colors which will not obscure the 
sight of the hands, as it is in reality the angle made by the 
two hands which is read instead of the figures. In proof 
of this may be cited the many advertising dials in which 
one letter takes the place of each character upon the dial 
and of the tower clocks in which the hours are indicated 
merely by blackened characters, being nothing less than an 
oblong blotch on the dial. Thousands of people will pass 
such a dial without ever noticing that the regular charac- 
ters do not appear. Various attempts have been made to 
change the colors and the sizes and shapes of the characters 
but comparatively few are successful. A black dial with 
gold characters and hands is generally accepted, or a cream 
dial with black hands, but any further experiments are 
dangerous except in the cases of tower clocks, which may 
have gold hands on any light colored dial, or a glass dial. 
In all such cases legibility is the main factor nought and 
the bright metal is far plainer for hands and chapters than 
anything that may be substituted for them. 

In tower clocks the rule is to have one foot of diameter 
of the dial for every ten feet of height. Thus a clock situ- 
ated one hundred feet above the ground level should have a 

4.6 



THE MODERN CLOCK. 427 

ten foot dial. On very large dials this rule is deviated from 
a little, but not much. All dials, except those of tower 
clocks, should be fastened to the movement, rather than to 
the case. This is particularly true where a seconds hand, 
with the small opening for the seconds hand sleeve, makes 
any twisting or warping of the case and consequent shift- 
ing of the dial liable to rub the dial against the sleeve at the 
seconds hand and thus interfere with the timekeeping. 

The wTiter has in mind a case in which a large number 
of fine clocks w^ere installed in a new brick and stone build- 
ing. They were finely finished and no sooner had they been 
hung on the damp w^alls than the cases commenced to swell 
and twist. It was necessary three times to send a man to 
move the dials which had been attached to these clocks. 
As there were about thirty clocks it will be seen that this 
was expensive. After the walls had dried out the cases be- 
gan to go back to the positions in which they were origin- 
ally, as the moisture evaporated from the cases, and the 
dials had consequently to be moved through another series. 
All told it took something like a week's work for one man 
to shift these dials half a dozen times during the first nine 
months of their installation. If these dials had been fas- 
tened on pillars on the movements, the shrinking and swell- 
ing of the cases would not have afifected them. 

It is for this reason that dials are invariably fastened on 
the movements of all high class clocks. 

The characters en clock dials are still very largely 
Roman, the numerals being known as chapters. Attem.pts 
have been recently made to substitute Arabic figures and in 
such cases the Arabic figures remain upright throughout the 
series, while the chapters invariably point the foot of the 
Roman numeral toward the center of the dial. This makes 
the Roman numerals from IIII to VIII upside down, Vv^hile 
in the Arabic numerals this inversion dees net cccr.r. 

The propcrtions [^cneral-v ca:ictio"cd by usage have been 
found, after measuring clock dials, all the Vv^ay from two 



428 THE MODERN CLOCK. 

to eighteen inches, and may be given in the following terms : 
With a radius of 26 mm. the minute circle is i^ mm. The 
margin between minute circles and chapters is i mm. The 
chapters are 8^ mm. The width of the thick stems of the 
letters are ^4 rnm. The width of an X is 4 mm. and the 
slanting of X's and V's is twenty degrees from a radius of 
the dial. The letters should be proportioned as follows: 
The breadth of an Tand a space should equal one-half the 
breadth of an X, that is, if the X is one-half inch broad, the 
I will be three-sixteenths inch broad and the space between 
letters one-sixteenth inch, thus making the I plus one space 
equal to one-quarter inch or half the breadth of an X. The 
V's should be the same breadth as the X's. After the let- 
ters have been laid off in pencil, outline them with a ruHng 
pen and fill in with a small camel's hair brush, using gloss 
black paint thinned to the proper consistency to work well 
in the ruling pen. Using the ruling pen to outline the let- 
ters gives sharp straight edges, which would be impossible 
with a brush in the hands of an inexperienced person. 

For tower clocks the chapters and minutes together will 
take up one-third of the radius of the dial ; the figures two- 
thirds of this, or two-ninths of the radius, and the minutes 
two-thirds of the remaining one-ninth of the radius, with 
every fifth minute more strongly marked than the rest. 

We often hear stories concerning the IIII in place of IV. 
The story usually told is that Louis XIV of France was in- 
specting a clock made for him by a celebrated watchmaker 
of that day and remarked that the IV was an error. It 
should be IIII. There was no disputing the King and so 
the watchmaker took away the dial and had the IIII en- 
graved in place of IV, and that it has thus remained in de- 
fiance of all tradition. 

Mr. A. L. Gordon, of the Seth Thomas Clock Co., has 
the following to say concerning this story and thus fur- 
nishes the only plausible explanation we have ever seen for 



THE MODERN CLOCK. 429 

the continuance of this manifest error in the Roman num- 
eral of the dial : 

"That the attempt has been made to use the IV for the 
fourth hour on clock dials, any one making a study of them 
may observe. The dials on the Big Ben clock in the tower 
of the Parliament buildings, London, which may be said to 
be the most celebrated clock in the world, have the IV 
mark, and the dial on the Herald building in New York 
City also has it. 

"That the IIII mark has come to stay all must admit, 
and if so there must be a good and sufficient reason. Art 
writers tell us that pictures must have a balance in the plac- 
ing and prominence of the several subjects. Most conven- 
tional forms are equally balanced about a center line or a 
central point. Of the latter class the well known trefoil is 
a common example. 

"A clock or watch dial with Roman numerals has three 
points where the numerals are heavier, at the IIII, VIII 
and XII. Fortunately these heavier numerals come at 
points equally spaced about the center of the dial and about 
a center line perpendicular to the dial. Of these three heavy 
numerals the lighter of them comes at the top and it is 
especially necessary that the other two, which are placed at 
opposite points in relation to the center line, should be bal- 
anced as nearly as possible. As the VIII is the heavier 
and cannot be changed, the balancing figure must be made 
to correspond as nearly as possible, and if marked as IV, 
it will not do so nearly as effectively as if the usual IIII is 
used." 

It is comparatively an easy matter to make a metal dial 
either of zinc, copper or brass, by laying out the dial as in- 
dicated above with Roman chapters and numerals, after 
first varnishing the metal with asphaltum. This may be 
drawn upon with needle points which cut through the 
asphaltum and make a firmly defined line on the metal. It 
is best to lay out your dial in lead pencil and then take a 



430 THE MODERN CLOCK. 

metal straight edge and a needle point and trace through 
on the pencil marks. Mistakes may be painted out with 
asphaltum, so that the job becomes easy. After this has 
been done a comparatively dull graver may be used to cut 
or scrape away the asphaltum wdiere the metal is to be 
etched and then the plate may be laid in a tray, a solution 
of chloride of iron poured on and rocking the tray will 
rapidly eat away the metal, forming sunken lines wherever 
the copper or brass is" not protected by the asphaltum. This 
furnishes a rough surface on the etched portions, which en- 
ables the filling to stick much better than if it were smooth. 
In tracing the circles a pair of heavy, stiff, carpenters' com- 
passes will serve where the watchmaker has not a lathe 
large enough to swing the dial. In all such cases it is best 
to start with a prick-punched center, tracing the minute 
circles and the serifs of the chapters with the compasses and 
then do your further division and marking by lead pen- 
cil, followed with the needle and then by the acids. It 
should be done before the holes are bored for the minute 
and seconds centers, as you then have an exact center to 
mark from and can go back to it many times. 

This will be necessary in 'dividing the minute or seconds 
circle by hand (without an index on the lathe), as one of 
the tests of true division consists in having all marks lined 
up with a straight edge placed across the center. Thus IX 
and III should be in line with the center; VI and XII; X 
and IIII; I and VII, etc. It will readily be seen that for 
such purposes of reference the center should not be punched 
too large. 

If it is desirable to ornament the dial, the desired orna- 
ment may be drawn on in the plain surface through the 
asphaltum and etched at the same time as the chapters and 
degrees. Or chapters and ornament may be drawn, pierced 
with a saw, engraved, filed up and backed up with a plain 
plate of another color. Gold ornament and silver back- 
ground looks well. 



THE MODKKN CLOCK. 43I 

Practically all the clocks having seconds hands carry that 
hand in such a position as to partially obscure the XII, 
with the exception of watchmakers' regulators, and these, 
if they have separate hour, minute and seconds circles, are 
made large enough to occupy the space between the center 
and the minute circle, placing the hour circle between the 
center and the thirtieth minute ; 'the seconds between the 
.center and the sixtieth minute. The reason for this is that 
in^the watchmakers' regulators the hours are almost a mat- 
ter of indifference ; minutes are reldom referred to ; the real 
coniparison in watch regulation comes on the seconds hand. 
For this reason the seconds hand is made as large as pos- 
sible and the chapters being placed on the hour circle by 
themselves, the seconds circle may occupy almost the en- 
tire distance between the center of the dial and the minute 
circle. They are placed one above the other because in 
regulators the tim.e train is nearly always a straight-line 
train, which brings the seconds arbor vertically over the 
center arbor, and consequently the centers of the dials must 
be placed on a vertical line. 

When the engraving has been properly done on a flat 
dial it is desirable to fill it with black in order to make it 
legible. There are several methods by which this may be 
done. The most durable is to make a black enamel and if 
it is a valuable clock the movement is generally worth a fine 
dial. The following formula will furnish a good black 
enamel : 

Siliceous sand 12 parts 

Calcined borax 20 parts 

Glass of antimony 4 parts 

Saltpetre 1 part 

Chalk 2 parts 

Peroxide of Manganese 5]/2 parts 

Fine Saxony Cobalt 2 parts 

The enamel is ground into coarse particles like sand, and 
the incised lines filled with it, after which the brass or cop- 



432 THE MODERN CLOCK. 

per plate is heated red hot to fuse the enamel. Two or 
three firings may be necessary to completely fill the lines ; 
after filling they arc stoned off level with the surface of the 
dial. Jeweler's enamel may be purchased of material deal- 
ers and used for the dials. 

Black asphaltum mixed with a little wax or pitch, or even 
watchmakers' cement, used to fasten staffs and pinions 
into a lathe for turning, is also used on these dials and with 
a sufiicient proportion of wax or pitch it prevents shrinking 
and forms a very satisfactory dial with the single exception 
that it cannot be cleaned with benzine or hot potash, which 
will dissolve the enamel. Shoemakers' heel ball is also used 
for repair jobs. In order to make either of these stick, the 
brass or copper plate is heated up so as to "hiss" as will a 
laundry flat iron when touched with a wetted finger, and 
a cement stick is rubbed over the letters to fill them; the 
excess of filling can be scraped off with an ivory scraper 
when at the right temperature — a little below the boiling 
point of water. Such filled letters can be lacquered over by 
going very quickly over the work so as not to dissolve the 
shellac in the cement. 

Another way is to fill the letters with black lacquer. For 
quick repairs this is probably as good as any. Many of the 
old grandfather clocks have been filled in with a putty made 
with copal varnish and some black pigment. All putties 
shrink in drying and consequently crack and finally fall out. 
The wax and pitch are not subject to these disadvantages. 
If the plates are to be polished, polishing should precede 
the filling in of the letters, else the work may have to be 
done all over again. Black sealing wax and alcohol are also 
used, applied as a paint w^th a fine brush. 

If the dial is to be silvered or gilt the blacking should be 
done first, and if to be electroplated the blacking should be 
what is known as the "platers' resist," which is composed 
chiefly of asphaltum and pitch dissolved in turpentine. It 
is also called "stopping-off" varnish, and has large use in 



THE MODERN CLOCK. 433 

the plating establishments to prevent deposition of metal 
where it is not desired. 

The repairer who gets many grandfather clocks will 
often find that it is necessary to repaint the dial, generally 
because of a too vigorous scrubbing, or because of crack-; 
or scaling, which the owner may dislike. It is always best, 
however, to be cautious in such matters, as many people 
value such a clock chiefly on account of its visible evidences 
of age and such cracks form generally a large proportion 
of such evidence. Therefore it is best never to touch an 
antique dial unless the owner desires it. 

Such dials are usually sheet-iron, and tolerably smooth, 
so the metal will need but a few coats of paint to prepare it. 
For ground coats, take good, ordinary white-lead or zinc 
white, ground with oil, and if it has much oil mixed with it 
pour "it off and add spirits of turpentine and Japan dryer — 
a teaspoonful of dryer for every half pint of paint.. The 
test for the paint having the right amount of oil left in it is, 
it should dry without any gloss. Rub every coat you apply 
with fine sand-paper, after it is perfectly dry, before apply- 
ing the next coat of paint. For the final coat, lay the dial 
flat and go over it with French zinc-white. This coat dries 
very slow, and for a person not used to such work, is hard 
to manage. The next best (and for ordinary clock or watch 
making the best) for the last pure white coat is to take a 
double tube of Windsor & Newton's Kremnitz white, 
thinned wath a little turpentine. Such tubes as artists use 
are the kind. Apply this last w^hite coat with a flat, camel's 
hair brush. The tube-white should have turpentine enough 
added to cause it to flow freely, and sink flat and smooth 
after the brush. The letters or figures should be painted 
with ivory-black, which is also a tube color. This black is 
mixed with a little Japan, rubbing-varnish and turpentine, 
and the lettering is done with a small, sign waiter's pencil. 
Any flowers or ornaments are painted on at the same time ; 
and after they are dry the dial should be varnished with 



/|34 '^^^ MODERN CLOCK. 

Mastic or Damar varnish or white shellac. All kinds of 
coach (Copal) varnish are too yellow. 

. Painted dials on zinc will blister and crack off if sub- 
jected to extremes of heat and cold, unless they are painted 
with zinc white instead of lead for all white coats. The rea- 
son is the great difference in expansion between lead paint 
and metallic zinc. This case is similar to that of using an 
iron oxide to paint iron work of bridges, ships, etc., where 
other oxides will chip and scale off. 

The metal dials on these old clocks were silvered by 
hand. When you get such a dial, discolored and tarnished, 
it can be. cleaned in cyanide and resilvered, without sending 
it to an clectroplater, by the following formula : 

Dissolve a stick of nitrate of silver in half a pint of rain 
water; add two or three tablespoonfuls of common salt, 
which will at once precipitate the silver in the form- of a 
thick, white curd, called chloride of silver. Let the chloride 
settle until the liquid is clear; pour off the water, taking 
care not to lose any chloride ; add more water, thoroughly 
stir and again pour off, repeating till no trace of salt or acid 
can be perceived by the taste. After draining off the water 
add to the chloride about two heaped tablespoonfuls each 
of salt and cream of tartar, and mix thoroughly into a paste, 
which, when not in use, must not be exposed to the light. 
To silver a surface of engraved brass, wash the curface 
clean with a stiff brush and soap. Heat it enough to melt 
black sealing wax, which rub on with a stick of wax until 
the engraving is entirely filled, care being taken not to burn 
the wax. With a piece of flat pumice-stone, and some pul- 
verized pumice-stone and plenty of water, grind off the 
wax until the brass is exposed in every part, the stoning 
being constantly in one direction. Finish by laying an even 
and straight grain across the brass with blue or water of 
Ayr stone. Take a small quantity of pulverized pumice- 
stone on the hand, and slightly rub in the same direction, 
which tends to make en even rT:rain ; the hands mmi be 



THE .MODERN CLOCK. 435 

entirely free from soap or grease. Rinse the brass thor- 
oughly, and before it dries, lay it on a clean board, and 
gently rub the surface with fine salt, using a small wad of 
clean muslin. When the surface is thoroughly covered with 
salt, put upon the wad of cloth, done up with a smooth sur- 
face, a sufficient quantity of the paste, say to a dial three 
inches in diameter a piece of tlie size of a marble, wdiich 
rub evenly and quickly over the entire surface. The brass 
will assume a greyish, streaked appearance ; add quickly to 
the cloth cream of tartar moistened with water into a thin 
paste ; continue rubbing until all is evenly whitened. Rinse 
quickly under a copious stream of water ; and in order to 
dry it rapidly, dip into water as hot as can be borne by the 
hands, and when heated, holding the brass by the edges, 
shake off as much of the water as possible, and rem.ove any 
remaining drops with clean, dry cloth. The bra^s should 
then be heated gently over an alcohol lamp, until the wax 
glistens without melting, when it may be covered with a 
thin coat of spirit varnish, laid on with a broad camel's 
hair brush. The varnish or lacquer must be quite light- 
colored — diluted to a pale straw color. 

It is now possible to buy silver plating solutions which 
can be used without battery and they will produce the same 
effect as the formula just given. If they happen to be in 
stock for the repairing of jewelry they may be used in 
cleaning the dials, but as this is liable to fall into the hands 
of many wdio are far from such conveniences, we furnish 
the original recipe, which can be executed anywhere the 
materials can be obtained. 

If the dial is of brass, very good effects have been pro- 
duced by stopping off portions of the dial in an ornamental 
pattern before silvering, and then lacquering after removing 
the resist. But for a plain black and brass dial a dip of 
strong sulphuric acid two parts, red fuming nitrous acid 
one part, and water one part, mixed in the open air and 
dipped or flowed over the dial, forms what is known as the 



436 THE MODERN CI-OCK. 

platers' bright dip. After dipping the article should at once 
be rinsed in hot water and dried, and lacquered at once with 
a' lacquer of light gold color. This makes a very neat and 
durable finish. 

The satin effect may be obtained on a dial by prolonging 
the acid dip and otherwise proceeding as before. Many of 
these dials were of zinc and all that applies to brass or cop- 
per may be also executed in zinc, but in plating it will be 
found necessary to plate two or three times, as the single 
coating will apparently disappear into the zinc unless it is 
given a heavy deposit of copper in a plating bath. Where 
it is desired to obtain a bright gold color, the gold plating 
solutions now sold for the coloring of jewelry may also be 
used on either of these metals. For the reasons given 
above, however, they are not very successful on a zinc 
base. 

Many of the cheap clocks have paper dials glued on a 
zinc plate and when the dial is soiled the repairer cleans 
them up by pasting another dial on top of the original. 
These dials are made on what is known as lithographic label 
paper: that is paper which is waterproof on one side, so 
that it will not shrink or swell when dampened. In addition 
to the lithograph coating they are generally given a varnish 
of celluloid by the clock manufacturers, thus making them 
practically waterproof. They are very cheap and the re- 
pairer will find that he will obtain in prestige from such 
new dials far more than they cost. 

Tarnished metal dials are best cleaned by a dip of cyanide 
of potassium, of about the same strength as that used for 
cleaning silver. If the tarnished parts have been gilded, 
however, the cyanide should be excessively weak. Mining 
men use a cyanide solution for the recovery of gold, which 
is only two-tenths of one per cent cyanide, and this will 
collect all the gold from ore that runs from $10 to $15 to 
the ton, the pulp in such cases being left in the solution 
from seventy to ninety hours. The ordinary cyanide dip 



THE MODERN CLOCK. 437 

for the jeweler is one ounce to thirty-two of water, while 
the miner's solution is two-tenths of an ounce to one hun- 
dred ounces of water. You can see that with the strong 
cyanide solution the gilt surface will all be taken off unless 
very rapid dipping is strictly followed by thorough wash- 
ing. 

A novelty which keeps periodically coming to the front, 
say about once every ten years, is the luminous dial. This 
is done by painting the dial with phosphorus or a phos- 
phorescent powder. Then when it is placed in the light it 
will absorb light and give it off in the dark until the evap- 
oration of the phosphorus. 

The composition and manufacture of this phosphores- 
cent powder is effected in the following manner: Take 
100 parts by weight of carbonate of lime and phosphate 
of lime, produced by calcination of sea-shells, especially 
those of the tridacna and cuttlefish bone, and lOO parts by 
weight of lime, rendered chemically pure by calcination. 
These ingredients are well miixed together, after which 25 
parts of calcinated sea salt are added thereto, sulphur being 
afterward incorporated therewith to the extent of from 25 
to 50 per cent of the entire mass, and a coloring matter is 
applied to the composition, which coloring matter consists 
of from 3 to 7 per cent of the entire mass of a pow^der com- 
posed of a mono-sulphide of calcium, barium, strontium, 
magnesium or other substance which has the property of 
becoming luminous in the dark, after having been impreg- 
nated with light. After these ingredients are well mixed, 
the composition is ready for use. Its application to clock 
dials is made either by incorporating suitable varnish there- 
with, such as copal, and applying the mixture with a brush 
to the surface of the dial, or by the production of a dial 
which has a self-luminous property, imparted to it during 
its manufacture. This is effected in the following manner : 
From 5 to 20 per cent of the composition obtained and 
formed as above described, is incorporated with the glass 



438 THE MODERN CLOCK. 

while it is in a fused state, after which the glass so pre- 
pared is molded or blown into the shape or article required. 
Another process consists of sprinkling a quantity of the 
composition over the glass article while hot, and in a semi- 
plastic state, by either of which processes a self-luminous 
property will be imparted to the article so treated. 

Where enamel dials are chipped the cracks may be hidden 
by first pressing the cracks very slightly open and washing 
out. Then work in a colorless cement to fill the crack, allow 
to dry and stone down. Where holes have been left by the 
chipping, melt equal parts of scraped pure white wax and 
zinc white and let it cool. Warm the dial slightly and press 
the cold wax into the defective places and scrape off with a 
sharp knife and it will leave a white and lustrous surface. 
If too hard add wax ; if too soft add some zinc white. 

Varnish for Dials, Etc. — A handsome varnish for the 
dials of clocks, watches, etc., may be prepared by dissolving 
bleached shellac in the purest and best alcohol. It offers 
the same resistance to atmospheric influence that common 
shellac does. In selecting bleached shellac for this purpose 
be careful to get that which will dissolve in alcohol, as some 
of it being bleached with strong alkalies, is thereby rendered 
insoluble in alcohol. The shellac when dissolved should 
be of a clear light amber color in the bottle and this will be 
invisible on white paper when dry. 

Colorless celluloid lacquer, known to jewelers as "silver 
lacquer" on account of its being used to prevent tarnish on 
finished hollow ware, also makes a good varnish to apply 
to dials, either metallic or painted. It is best to have it 
thin, flow it on the dial and then level the dial to dry. 

Success in the repairing of a broken enameled clock dial 
will greatly depend upon the practical skill of the operator, 
as well as of a knowledge of the process. If it is only de- 
sired to repair a chipped place on a dial, a fusible enamel of 
the right tint should be procured from a dealer in watch- 



THE MODERN CEOCK. 439 

makers' materials, which, with ordinary care, may be fused 
on the chipped place on the dial so as to give it a workman- 
like appearance when finished off. The place to receive the 
enamel should be well cleaned, and the moist enamel spread 
over the place in a thin, even layer; and, after allowing it 
to dry, the dial may be held over a spirit lamp until the new 
enamel begins to fuse, when it may be smoothed down with 
a knife. The dial, after this operation, is left to cool, when 
any excess of enamel may be removed by means of a corun- 
dum file, and subsequently polished with putty powder 
(oxide of tin). The ingredients of enamel, after being 
fused into a mass, are allowed to cool, then crushed to 
powder and well washed to get rid of inpurities, and the re- 
sulting fine powder forms the raw material for enameling. 
It is applied to the object to be enameled in a plastic con- 
dition, and is reduced to enamel by the aid of heat, being 
.first thoroughly dried by gentle heat, and then fused by a 
stronger one. The following is a good white enamel for 
dials : 

Silver sand, 3 ounces ; red lead, 3^ ounces ; oxide of tin, 
2.y2 ounces ; saltpeter, ^ ounce ; borax, 2 ounces, flint glass, 
I ounce ; manganese peroxide, 2 grains. The basis of nearly 
all enamels is an easily fusible colorless glass, to which the 
required opacity and tints are given by the addition of var- 
ious metallic oxides, and these, on being fused together, 
form the different kinds of vitreous substances used by 
enamel workers as the raw material in the art of enameling. 

The hands of timekeepers are worthy of more attention 
than is frequently bestowed upon them by watch and clock- 
makers. Their shape and general arrangement, and the 
neatness of their execution is often taken by the general 
public as an index to the character of the entire mechanism 
that moves them; and some are apt to suppose that when 
care is not bestowed on the parts of the time-piece which 
are most seen, much care cannot be expected to have been 
exercised on the parts of the watch or clock which are in- 



440 THE MODERN CLOCK. 

visible to the general view. Although we are not prepared 
to fully endorse the opinion that when the hands of time- 
pieces are imperfect in their execution, or in their general 
arrangem.ent, all the mechanism must of necessity be im- 
perfect also; still we think that in many instances there is 
room for improving the hands of timepieces, and we desire 
to direct more attention to this subject by the workmen. 

In the general arrangement of the hands of watches and 
clocks, distinctness of observation should be the great point 
aimed at, and everything that has a tendency to lead to con- 
fusion should be carefully avoided. Clocks that have a 
number of hands radiating from one center, and moving 
round one circle — as for instance, center seconds, days of 
the month, equation of time, alarms and hands for other 
purposes — may show a good deal of mechanical skill on the 
part of the designer and maker of the timepiece ; but so 
many hands moving together around one circle, although 
they may be of different colors, causes confusion, and re- 
quires considerable effort to make out what the different 
hands point to in a dim light, and this confusion is fre- 
quently increased by the necessity for a counterpoise being 
attached to some of the hands. As a rule timekeepers should 
be so arranged that never more than the hour and minute 
hand should move from one center on the dial. There may 
be special occasions when it is necessary or convenient to 
have center seconds to large dials ; but these occasions are 
rare, and we are talking about the hands of timekeepers 
in every-day use for the ordinary purposes of life, and also 
for scientific uses. In astronomical clocks and watchmakers' 
regulators we find the hour, minute and second hands mov- 
ing on separate circles on the same dial ; and the chief rea- 
son for this arrangement is to prevent mistakes in reading 
the time. In chronometers, especially those measuring- side- 
real time, the hour hand is frequently suppressed, and the 
hours are indicated by a star wheel, or ring, with figures 
engraved on it, that show through a hole in the dial. 



THE MODE UN CLOCK. 



^41 



Hour and minute hands should be shaped so that the one 
can be easily distinguished from the other without any ef- 
fort on the part of the observer. Probably a straight minute 
hand, a little swelled near the point, and a spade hour hand, 
are the shapes best adapted for this purpose, especially if 
the hands have to be looked at from a distance. There are 
occasions, however, when a spade hand cannot be used with 
propriety. In small watches and .clocks having ornamental 
cases, hands of other designs are desirable, but whatever 
be the pattern used, or whatever color the hands m.ay be 
made, it should ever be remembered that wdiile a design in 
harmony with the case is perfectly admissible, the sole use 
of hands is to mark the time distinctly and readily. 

The difference in the length of the hour and minute hands 
is also an important point in rendering the one easily dis- 
tinguished from the other. The extreme point of the hour 
hand should extend so as to just cover the edge of the in- 
side end of the numerals and the extreme point of the 
minute hand should cover about two-thirds of the length of 
the minute divisions. Hands made of this length will be 
found to mark the hours and minutes with great plainness, 
and the rule will be found to work well in dials of all sizes. 
As a general rule, the extreme points of the hands should 
be narrow. The point of the hour hand should never be 
broader than the thickest stroke of any of the numerals, 
and the extreme point of the minute hand never broader 
than the breadth of the minute lines ; and in small work it is 
well to file the ends of the hands to a fine point. The ends 
of minute hands should in every instance be bent into a 
short, graceful curve pointing toward the dial, and as close 
to it as will just allow the point of the hand to be free. The 
minute hands of marine chronometers are invariably bent 
in this manner, and the hands of these instruments are 
usually models of neatness and distinctness. 

Balancing hands by means of a counterpoise is a subject 
which requires some attention in order to effect the perfect 



442 THE MODERN CLOCK. 

poise of the hand without detracting anything from its dis- 
tinctness. In watch work, and even in ordinary clock- work, 
it seldom happens that any of the hands except the seconds 
require to be balanced, and then there is only one hand mov- 
ing round the same circle, as is the case with seconds hands 
in general. We have become so accustomed to looking at 
seconds hands with projecting tails that we are apt to re- 
gard the appearance of the hands to be incomplete without 
the usual tail ; but we must remember that the primary ob- 
ject in view in having a tail to a seconds hand is to counter- 
poise it, not to improve the looks of the hand itself. Poising 
becomes an actual necessity for a hand placed on so sensi- 
tive a part as the fourth wheel of a watch, or on the scape 
wheel of a fine clock. When only one hand moves in the 
same circle, like a seconds hand, the counterpoise may be 
effected by means of a projecting tail without in any way 
detracting from a distant reading of the hands, providing 
the tail is not made too long, and it is made of such a pat- 
tern that the one end can easily be distinguished from the 
other. In minute and hour hands, however, it is different. 
These two hands move round the same circle, and a coun- 
terpoise on the minute hand is liable at a distance to be mis- 
taken for the hour hand. 

The minute hands of large timepieces frequently require 
to be balanced, especially if the dial be large in comparison 
to the size of the movement; and in very large or tower 
clocks, whatever may be the size of the movement, it be- 
comes an absolute necessity to balance the hands. In our 
opinion, tails should never be made on minute hands, when 
they can be avoided, and in cases where tails cannot be dis- 
pensed with, they should invariably be colored the same as 
the ground of the dial. In almost every instance, however, 
minute hands may be balanced in the inside, as is usual with 
tower clocks. A great many clocks used for railway and 
similar purposes in Europe have their minute hands bal- 
anced in this manner, and the plan works admirably ; for in 



THE MODERN CLOCK. 



443 




Fig. 150. Showing counterpoise on arbor of minute hand in tower clock. 



444 THE MODERN CLOCK. 

addition to rendering the hands more distinct, the clocks re- 
quire less power to keep them going than when the hands 
are balanced from the outside. 

Tower clock hands are generally made of copper, elliptical 
in section, being made up of two circular segments brazed 
together at the edges, with internal diaphragms to stiffen 
them. The minute hand is straight and perfectly plain, with 
a blunt point. At the center of the dial the width of the 
minute hand is one-thirteenth of its length, tapering to 
about half as much at the point. 

The hour hand is about the same width, ending jus|: short 
of the dial figure and terminating in a palm or ornament. 
The external counterpoises are one-third the length of the 
minute hand, and of such a shape that they will not be con- 
founded with either of the hands ; a cylinder, painted the 
same color as the dial, and loaded with lead, makes a good 
counterpoise. This counterpoise may be partly on the in- 
side of the dial if it is desired to keep it invisible, but it 
should not be omitted, as it saves a good deal of power, pre- 
vents the twisting of the arbors, and also assists in over- 
coming the action of the wind on the hands. Two-thirds 
of the counterpoise weight may be inside, as shown in Fig. 
150. 

To Blue a Clock Hand or a Spring. — To blue a piece 
of steel that is of some length, a clock hand for example, 
clockmakers place it either on ignited charcoal, with a hole 
in the center for the socket, and whitened over its surface, 
as this indicates a degree of heat that is approximately uni- 
form, or on a curved bluing tray perforated with holes 
large enough to admit the socket. The center will become 
violet or blue sooner than the rest, and as soon as it assumes 
the requisite tint, the hand must be removed, holding it with 
tweezers by the socket, or by the aid of a large sized arbor 
passed through it ; the lower side of the hand is then placed 
on the edge of the charcoal or bluing tray, and removed by 



THE MODERN CLOCK. 445 

gradually sliding it off toward the point, more or less slowly, 
according to the progress made with the coloring; with a 
little practice, the workman will soon be enabled to secure 
a uniform blue throughout the length and even, if necessary, 
to retouch parts that have not assumed a sufficiently deep 
tint. 

Instead of a bluing tray, a small mass of iron, with a 
slightly rounded surface and heated to a suitable tempera- 
ture, can be employed ; but the color must not form too 
rapidly, and this is liable to occur if the temperature of the 
mass is excessive. Nor should this temperature be unevenly 
distributed. 

A spring, after being whitened, can be blued in the same 
way. Having fixed one end, it is stretched by a weight at- 
tached to the other end^ and the hot iron is then passed 
along it at such a speed that a uniform color is secured. Of 
course, the hot iron might be fixed and the spring passed 
over it. A lamp may be used, but its employment involves 
more attention and dexterity. 



CHAPTER XXIII. 

CLOCK CASING AND CASE REPAIRS. 

Precision Clock Cases. — The casing of a precision 
clock is uiily secondary in importance to the comoensation 
of its pendulum. The best construction of an efficient case 
can be ascertained only by most careful study of the con- 
ditions under which the clock is expected to be a standard 
timekeeper, and often the entire high accuracy sought by re- 
fined construction is sacrificed by an inefficient case and 
mounting. 

The objects of casing a precision clock are as follows 

a. To protect the mechanism from the effects of dust 
and dirt, 

b. To avoid changes of temperature and barometric 
pressure. 

c. To provide an enclosed space in which the gas me- 
dium in which the pendulum swings shall have any chem- 
ical constitution, of any hygroscopic condition. 

d. There must be provided ready means of seeing and 
changing the condition of the pendulum, electric apparatus, 
movement, etc., without disturbing the case except locally. 

Now if we hold the above considerations in view we can 
readily see that cast iron, wood and glass, with joints of 
wash leather (which is kept soft by a wax cement which 
does not become rancid with age), are the preferable ma- 
terials. 

The advantages of using cast iron for the pillar or body 
of the case are that it can b'e cast in such a shape as to re- 
quire very little finishing afterwards, and that only such 
as planing parallel surfaces in iron planing machines. It 

446 



THE MODKI^N CLOCK:. 



447 



makes a stiff column for mounting the pendulum when it 
rests upon a masonry foundation from below. Plates of 
glass can be clamped against the planed surfaces of iron 
piers (by putting waxed wash leather between the glass and 
the iron) so as to make air-tight joints without difficulty. 

The mass' of iron symmetrically surrounding the steel 
pendulum is the safest protection the clock can have against 
casual magnetic disturbances. In the language of elec- 
tricians it ''shields" the pendulum^. 

Suppose, then, we adopt as the first type of precision 
clock case which our present knowledge suggests, that of an 
Iron cylinder or rectangular box resting on a m.asonry pier, 
and which has a table top to which the massive pendulum 
bracket is firmly bolted. This type admits of the weights 
being dropped in small cylinders outside of the cast iron 
cylinder or box. These weight cylinders, of course, end In 
the table top of the clock case above and in the projecting 
base of the flange of the clock case below. 

With this construction it is a simple matter to cover the 
movement with a glass case, preferably made rectangular, 
with glass sides, ends and top, with rtietal cemented joints. 
The metal bottom, edges of this rectangular box can be 
ground to fit the plane surface of the top of the clock case. 
Then, by covering the bottom edges with such a wax as was 
used in making the glass plates fit the iron case in front or 
back, we can secure an air-tight joint at the junction of the 
rectangular top glass case wath iron case. In practice the 
W2LX to be used may be made by melting together and stir- 
ring equal parts of vaseline and beeswax. The proportions 
may be varied to give a different consistency of wax, and It 
may be painted on with a brush after warming over a small 
flame. 

If the clock case will be exposed to a comparatively high 
temperature, say 95° F., then the beeswax can be 3 parts to 
I of vaseline. The good quality of this cement wax Is that 
it does not change with age, or at least for several years. 



448 THE MODERN CLOCK. 

is very clean, and can be wiped off completely with kerosene, 
or turpentine, or benzine. In all joints meant to be air-tight, 
the use of rubber packing is to be avoided. It answers well 
enough at the start, but after several months it is sure to 
crack and leak air. 

By an air-tight joint I do not mean a joint which will not 
leak air under any pressure w^hich may be applied. It is not 
necessary that our pendulum should vibrate in a vacuum; 
all we want is that the pressure inside the clock case should 
be uniform ; that it should not vary with the barometer out- 
side. In actual practice we find it best to iTave the pressure 
inside the case as nearly as possible equal to the average 
atmospheric pressure outside. Now, if the barometer in a 
given locality never sinks below 27.5 inches, it is not neces- 
essary that the vacuum in the clock case be less than that 
represented by 29.5 inches of mercur)- pressure. So, too, 
if it were desirable to have the pressure inside the case great- 
er than that outside, owing to some special form of joint 
which made the clock case less liable to leak out than to 
leak in, it might be that an inside pressure would be effi- 
cient at 31 inches of mercury. By not having the inside 
pressure vary but slightly from the outside, the actual pres- 
sure of air will not exceed one inch of mercury, or, say, 
y2 pound pressure to the square inch. This is a pressure 
which causes quite an insignificant strain upon any joint. 

There are objections, however, to the use of air in an en- 
closed space for precision clocks and so the attempt has been 
made to tise hydrogen. Air is, comparatively speaking, 
heavy. It is 14 J/2 times as heavy as hydrogen gas, for in- 
stance. The pendulum, therefore, in moving through its 
arc has to push aside 14 times as much weight as it would 
have to in case it were surrounded by hydrogen. Then 
what might be called the ''case friction" is greater than if 
we used hydrogen. By "case friction" I mean resistance 
and a disturbance to the pendulum depending on the effect 
of the currents of air produced by driving the air before the 



THE MODERN CLOCK. ^/^g 

pendulum against the sides and front of the case. It is 
a well-established observation that small, cramped cases dis- 
turb the clock's rate more than large, roomy ones. This is 
because the air, having no room to go before the pendulum, 
is cushioned up against the side of the case at each pendu- 
lum swing, and acts as a resisting spring against the swing 
of the pendulum. By the time the pendulum has reached 
the end of its vibration the air has escaped upwards and 
downwards perhaps so that it no longer has its spring power 
to restore the loss of energy to the pendulum. This "case 
friction" is most pernicious in its action when associated 
with free falling weights in the clock case. Clock weights 
should always fall in separate compartments, and never in 
such a manner that they can affect the space in which the 
pendulum swings. 

But this is a digression to explain the term "case friction" 
in its use in horology. 

Precision clocks, almost without exception, have electric 
break-circuit attachments within -the case. Most of these 
break-circuits are constructed so that there is a small spark 
every time the circuit is broken. The effect of such a spark 
in air is to convert a small portion of the air in the imme- 
diate neighborhood of the spark into nitrous acid gas. 
After several months there might be a considerable quantity 
of this gas in the case, with the certain result of rusting the 
nicer parts of the escapement. 

Many attempts have been made to run a clock in an 
almost complete vacuum of air; but the volume to be ex- 
hausted is so large, and the leakage is so sure to occur after 
a time, that the attempt is now pretty generally abandoned. 
It will be inferred from what has preceded that a full atmos- 
phere of hydrogen would only offer one-fourteenth the re- 
sistance to the pendulum that air would, and all the disturb- 
ances arising from the surrounding mediums would be only 
one-fourteenth for hydrogen of that which we would ex- 
pect for air. Every consideration, therefore points to the 



45© THE MODERN CLOCK. 

use of hydrogen as the medium with which to fill our clock 
cases. It is inert, it forms no compounds under the influ- 
ence of the electric spark, the case friction is no greater 
than would exist if we made an air vacuum of only about i 
inch of mercury, and hydrogen gas may be readily prepared. 
The method from dilute sulphuric acid and scrap zinc is the 
handiest, and it will be found described in almost any chem- 
istry textbook or encyclopedia. Should the horolo- 
gist wish to know something of the chemistry of 
the process, without pervious study, he will find 
it described in very simple language in any pri- 
mary chemistry. The practical details of filling a clock 
case with hydrogen gas I have not yet worked out. It is 
evident that since hydrogen is 143^ times lighter than 
air, that by attaching a small tube to the source of hydrogen 
and to the top of the clock case, and another small outlet 
tube at the bottom of the clock case, that by gravity alone 
the hydrogen would fill the upper part of the case and drive 
the air before it out at the bottom. The hydrogen should 
be dry. To insure this it should pass through a tube con- 
taining quicklime, which, if it is a foot long and two inches 
in diameter, will be sufficient. No burning light or electric 
spark must be put into the case while filling, because the 
mixture of hydrogen with the air is very explosive when 
ignited. Great care must be used in making all joints 
when attempting to maintain an atmosphere of hydrogen 
as it leaks readily through the pores of wood iron and all 
joints. It is, therefore, better to treat the case friction as 
a constant element and simply keep it constant. 
. The above discussion has not considered the temperature 
question. It is important that the changes of temperature 
in a clock case should be as slow as possible and as small as 
possible. Professor Rogers, of the Harvard College Ob- 
servatory, has shown that such bars as are used in pendu- 
lum rods of clocks are often several hours in taking up 
air temperatures m.any degrees different from that in which 



THE MODERN CLOCK. 45I 

they were swinging. We have at the top of the pendulum 
a thin spring for suspension whose temperature decides 
its molecular friction ; then we have the pendulum rod, and 
lastly the large bob, all of which take up any new tempera- 
ture with different degrees of slowness. Now obviously no 
compensation can be made to act unless the temperatures are 
the same for all parts of the pendulum, and vary at the 
same rate. A number of years ago, there was a long discus- 
sion as to the temperature at the top and bottom of clock 
cases. It was shown that this regularly amounted to several 
deofrees in the best clocks. It was to lessen this difference 
that at the Harvard College Observatory the Bonds built a 
deep well in the cellar, purposing to put the clock at its 
bottom. The idea was a good one, and were it not for the 
difficulty in getting at clocks in wells, and keeping water 
out, it would doubtless find favor where the*utm.ost accu- 
racy is desired. 

A better plan is to run the clock at a high temperature, 
say 95° to 100° F. The oil is more liquid, the temperature 
can be more easily maintained, it can all take place in light- 
ed, dry rooms, and the means for doing this we shall now 
consider. 

Our iron case must now be housed in another outside 
case, which had better be of wood, with glass windows for 
seeing the clock face. A single thickness of wood would 
conduct heat too rapidly. It must therefore be made of 
two thicknesses, with an air space between. If the air 
space is left unfilled, the circulation of the air soon causes 
the inner wooden layer to be of the same temperature as the 
outer. It is necessary to prevent this circulation of air 
therefore by means of some substance which is a non-con- 
ductor of heat and which will prevent the air from circu- 
lating. The very best thing to be used in this connection is 
cotton batting, which has been picked out until it is as light 
and fibrous as possible. Then if the doors and windows 
of the Vv'ooden case are made of two thicknesses of extra 



452 



THE MODERN CLOCK. 



thick glass, and are firmly clamped, by screws through their 
sashes or some other means, to the frame of the case, we 
have the best form possible for our completed case of the 
type I have described. It now remains to provide a layer 
of hot water pipes inside the clock room, heated by circula- 
ting hot water from the outside. The flame under the 



DDDiDDnlDDDlDDDlnDnlDDDlODDlDDdDDDlDgDlDDD 



I . I I . I ."m 



1 r 



HESSiigaaSiSBigiBBlESslB) 




Fig. 151. Section tlirough dock room of the Waltliam Watcli Company 



water tank outside, whether of gas or kerosine, to be auto- 
matically raised or lowered by any such thermostat arrange- 
ments as are in common use with chicken incubators, when 
the temperature varies from the point desired. Experience 
teaches that the volume of water had better be considerable, 
if there is considerable difference in the annual variations of 
temperature according to the seasons. Thus in Massa- 



THE MODERN' CLOCK. 453 

chnsetts or Illinois the temperature is likely to vary irom 
— 30° F. to + 110° F., and the heating arrangements must 
be suitable to take care of this variation. 

The Waltham Watch Company's clock room is an excel- 
lent example of the means taken to secure uniformity of 
temperature and absence of vibration. 

The clock room, which is located in the basement of one 
of the buildings, is built with a double shell of hollow tile 
brick. The outer shell rests upon the floor of the basement, 
and its ceiling is within two or three inches of the base- 
ment ceiling. The inner shell is lo feet square and 8 feet 
in height, measured from the level of the cellar floor. There 
is an i8-inch space between the walls of the inner and outer 
shell and a 9-inch space between the two ceilings. On the 
front of the building the walls are three feet apart to ac- 
commodate the various scientific instruments, such as the 
chronograph, barometer, thermostat, level-tester, etc. The 
inner house is carried down four feet below the floor of the 
basement, and rests upon a foundation of gravel. The walls 
of the inner house below the floor level consist of two thick- 
nesses of brick with an air space between, and the whole 
of the excavated portion is lined, sides and bottom, with 
sheet lead, carefully soldered to render it watertight. At 
the bottom of the excavation is a layer of 12 inches of sand, 
and upon this are built up three solid brick piers, meas- 
uring 3 feet 6 inches square in plan by 3 feet in height, 
which form the foundation for the three pyramidal piers 
that carry the three clocks. The interior walls and ceilings 
and the piers for the clocks are finished in white glazed 
tiling. The object of the lead lining, of course, is to thor- 
oughly exclude moisture, while the bed of sand serves to 
absorb all waves of vibration that are communicated 
through the ground from the various moving machinery 
throughout the works. At the level of the basement floor a 
light grating provides a platform for the use of the clock 
attendants. 



454 THE MODERN CLOCK. 

Although the placing of the clock room in the cellar and 
the provision of a complete air space around the inner room 
would, in itself, afford excellent insulation against external 
changes of temperature, the inner room is further safe- 
guarded by placing in the outer 1 8-inch space between the 
two walls a lamp which is electrically connected to, and 
controlled by, a thermostat. The thermostat consists of a 
composite strip of rubber and metal, which is held by a 
clamp at its upper end and curves to right or left under 
temperature changes, opening or closing, by contact points 
at the lower end of the thermostat, the electrical circuit 
which regulates the flame of the lamp. The thermostat is 
set so as to maintain the space between the two shells at a 
temperature which shall insure a constant temperature of 
71 degrees in the inner clock house. This it does with such 
success that there is less than half a degree of daily 
variation. 

The two clocks that stand side by side in the clock room 
serve to keep civil time, that is to say, the local time at the 
works. The clock to the right carries a twelve-hour dial 
and is known as the mean-time clock. By means of elec- 
trical connections it sends time signals throughout the whole 
works, so that each ■ operative at his bench may time his 
watch to seconds. The other clock, known as the astronom- 
ical clock, carries a twenty-four-hour dial, and may be con- 
nected to the works, if desired. These two clocks serve as a 
check one upon the other. They were made at the works 
and they have run in periods of over two months with a 
variation of less than 0.3 of a second, or 1-259,000 part of a 
day. The third clock, which stands to the rear of the other 
two, is the sidereal clock. It is used in connection with the 
observatory work, and serves to keep sidereal or star time. 

The rate, as observed at the Waltham works, rarely ex- 
ceeds one-tenth of a second per day. That is to say, the 
sidereal clock will vary only one second in ten days, or 
three seconds in a month. The variation, as found, is cor- 



THE MODERN CLOCK. 455 

rected by adding or subtracting weights to or from the 
penduhim, the weights used being small disks, generally of 
aluminum. 

Summing up, then, we find that the great accuracy ob- 
tained in this clock room is due to the careful elimination 
of the various elements that would exercise a disturbing in- 
fluence. Changes of temperature are reduced to a minimum 
by insulation of the clock house within an air space, in 
which the temperature is automatically maintained at an 
even rate. Changes of humidity are controlled by the spe- 
cially designed walls, by the lead sheathing of the founda- 
tion pit, by the preservation of an even temperature, and 
by placing boxes of hygroscopic material within the inner 
chamber. Errors due to vibration are eliminated by plac- 
ing the clocks on massive masonry piers which stand upon 
a bed of sand as a shock-absorbing medium. 

The astronomical clock is inclosed in a barometric case, 
fitted with an air pump, by which- the air may be exhausted 
and the pendulum and other moving parts relieved from 
barometric disturbances. For it must be understood that 
variation in barometric pressure means a variation in the 
density of the air, and that the speed of the pendulum must 
necessarily be affected by such changes of density. 

Restoring Old Cases. — Very often the watchmaker gets 
a clock which he knows will be vastly improved by varnish, 
but not knowing how to take off the old varnish he simply 
gives it a little sand paper or rubs it oft with oil and lets it 
go at that. Varnishing such a clock thinly with equal parts 
of boiled oil and turpentine and allowing it to dry will often 
restore the transparency of the varnish ; if uneven results 
are obtained a second coat may be necessary. Many of 
these old clocks have not been varnished for so many years 
that the covering of the wood looks like a cheap brown 
paint. To remove this in the ordinary way means endless 
labor, and if the case is inlaid with colored patterns of 



456 THE MODERN CLOCK. 

veneers, which are partly loosened by the glue drying out, 
the repairer is afraid to touch it for fear he will only make 
matters worse in the attempt to better them. 

In the case of an old clock of inlaid marquetry, if the 
pieces of veneer have become partly loosened, the first thing 
to do is to make a thin, fresh glue. Work the glue under 
the veneer and then clamp it down tightly with a piece of 
oiled paper, or waxed paper, laid between the glue and the 
board used to clamp with and the whole firmly set down 
tight with screws or screw clamps. To make waxed paper 
dissolve paranne wax in benzine and flow or brush on the 
paper and let dry. After the glue has hardened comes the 
work of removing the varnish. To do this you will need 
some varnish remover, which can either be bought at the 
paint store, or made as follows : 

Varnish Remover. — In doing such work the trick is to 
make sure that nothing put on the case will injure it, as a 
clock one hundred years old cannot be replaced. Therefore, 
if you are suspicious as to the varnish removers you can 
purchase, and do not want to take chances, you may make 
one of wood alcohol and benzole, or coal tar naphtha. Be 
sure you do not get petroleum naphtha, which is common 
gasoline. The coal tar naphtha is a wood product. The 
wood alcohol is also a wood product and the varnishes used 
upon furniture are vegetable gums, so that it will readily 
be seen that you are putting nothing on the antique with 
which it was not associated in its natural state. Equal parts 
of benzole and wood alcohol will dissolve gums instantane- 
ously, so that if the oil has dried out of the varnish so much 
that the varnish has become opaque and only the rosins are 
left, the application of this fluid with a brush will cause in- 
stant solution, making the gums boil up and form a loose 
crust upon the surface of the wood, as the liquid evaporates, 
which it does very rapidly. 



THE MODERN CLOCK. 457 

Varnishes containing shellac and some other gums are 
rather hard to dissolve and where an obstinate varnish is en- 
countered it may be well to use wax in the varnish remover. 
This is done by shaving or chopping some parafine wax, 
dissolving it in the benzole, and when it is clear and trans- 
parent, add the wood alcohol. Upon the addition of the 
alcohol the wax immediately curdles so that the fluid be- 
comes milky. In this condition it is readily brushed upon 
any surface and when the wax strikes the air it congeals and 
forms a crust which holds the liquid underneath and enables 
it to do its work instead of evaporating. 

The wax also serves the purpose of allowing the workman 
to see just where he Is putting his fluid and of holding it in 
position upon vertical surfaces or ceilings, round moldings, 
carved work and other places from which it will quickly 
run off. Only enough wax should be added to make it 
spread readily with the brush and after soaking it will be an 
easy matter to take a painter's putty knife, a case knife, or a 
scraper and laying it nearly flat on the wood remove all the 
varnish at one operation, wiping off the knife as fast as it 
becomes too full. After the bulk of the varnish Is off some 
of the fluid, without the wax, may be used upon a cloth to 
go over and smooth up by removing the spots and stripes of 
varnish left by the knife, or in moldings, etc., where the 
knife cannot be applied, and we have our bare wood, which, 
after drying and sand papering, is ready for a fresh coat of 
XXX coach varnish, which should dry in 24 hours and 
harden in a week. 

A very little work and practice in this will enable the 
workman to rapidly and cheaply clean up and repair an- 
tiques in such a way that it will add greatly to his repu- 
tation. 

To restore the gloss of polished wood it Is not always the 
best plan to employ true furniture polish. The majority of 
the so-called polishes for wood are based on a mixture of 
boiled linseed oil and shellac varnish, made by dissolving 



45^ THE MODERN CLOCK. 

shellac in alcohol in the proportion of four ounces of shellac 
to a pint of alcohol. A little of the dissolved shellac is 
poured on to a canton-flannel rag, a few drops of the boiled 
linseed oil are placed on the cloth, and the wood to be pol- 
ished is rubbed vigorously. About half an ounce of cam- 
phor gum dissolved with the shellac in the alcohol will 
greatly facilitate the operation of polishing. 

A soft woolen rag, moistened with olive oil and vigorously 
rubbed on dull varnished surfaces, like old clock cases, will 
brighten the surface wonderfully. Some workmen add a 
few drops of a strong solution of camphor gum in alcohol 
to the olive oil. 

The polishing of cases is accompHshed by applying sev- 
eral coats of the best coach painters' rubbing varnish, when, 
after perfect drying, the surface is rubbed with a felt or a 
canton-flannel rag, folded flat, using water and the finest 
pulverized pumic stone. This operation smooths the sur- 
faces. The final polishing of such work is done by rubbing 
with rotten stone and olive oil with the smooth side of 
canton flannel. To remove the last traces of smear caused 
by the oil, an old, soft linen cloth and rye flour is used. Of 
course, fine work like we see on new cases of fine quality is 
not likely to be produced by one who is unaccustomed to it; 
a man must serve a good, long apprenticeship in the varnish 
finishing business before he is competent for it; and even 
then some polishers fail to obtain the fine results achieved by 
others. The great danger is that the rubber will cut 
through the varnish and expose the bare wood on edges, cor- 
ners and even in spots on plane surfaces, before he has re- 
moved the lumps and streaks of varnish on adjacent portions 
of the work. Whenever the varnish is flat and smooth in 
any spot, you must stop rubbing there. 

Black wood clocks which have become smoked and dull 
should have the cases rubbed with boiled oil and turpentine 
on a piece of soft woolen rag ; afterwards polish off with 
a dry rag. If the gloss has been destroyed it will have to be 



THE MODERN CLOCK. 459 

varnished. Flow the varnish well on and use i^-inch 
brush and be careful to get the varnish on even and so as not 
to trickle. This is easy if you are careful to keep the var- 
nish thin and do not go over the varnish a second time 
after spreading it on. Thin with turpentine and put very 
little on the case ; it is already smooth and a mere film will 
give the gloss. For white filling on the engraving on black 
cases use Chinese white or get a good white enamel at a 
paint store. 

Gilding on wood cases is done by mixing a little yellow 
dry color with thin glue and painting the cases with the 
mixture ; the color lets you see what you are doing. When 
the glue has dried until it is "tacky," lay gold leaf on the 
painted portions and smooth down with cotton. If you have 
any holes do not attempt to patch them. It is easier and 
quicker to put on another sheet of gold leaf over the first 
one. After the gold is dry, it may be burnished with a 
bloodstone or smooth steel burnisher, or it may be left dead. 
Finish with colorless lacquer, very thin and smooth. 

Imitation gold leaf, known to the trade as Dutch Mietal, 
may be substituted for the gold leaf, if the latter is thought 
to be too expensive, but in such cases be sure to have the 
metal well covered with the lacquer, as unless this is done 
it will blacken in two or three years — sometimes in two or 
three months. 

Bronze powder may be applied to the glue size with a tuft 
of cotton and well rubbed in until flat and smooth ; then 
lacquer and dry. Never put on bronze paint, for the follow- 
ing reason : If we examine the bronze under a microscope 
we shall find that it is composed of flat scales like fish scales; 
if mixed as a paint they will be found lying at all angles in 
the painted work — many standing on edge. Such scales 
reflect the light away from the eye and make the work look 
dull and rough. If we rub these dry scales in gently on the 
sticky size, we will lay them all down flat and smooth,- so 
that the work will glisten all over with an even color. Al- 



460 THE MODERN CLOCK. 

ways lacquer bronzed work — yellow lacquer being the best 
— and put on plenty of lacquer. 

Metal ornaments, when discolored, should be removed 
from the case, dipped in boiling lye to remove the lacquer, 
scratch brushed, dipped in ammonia to brighten, rinsed in 
hot water and dried in sawdust. They may then be lac- 
quered with a gold lacquer, or plated in one of the gold 
plating solutions sold by dealers for plating without a bat- 
tery and then lacquered, if bright. If they are of oxidized 
finish cleaning and lacquering is generally all that is neces- 
sary. 

Oxidized metal cases, if badly discolored, should be sent 
to an electroplater to be refinished, as the production of 
smooth and even finishes on such cases, requires more skill 
than the clock repairer possesses, and he therefore could 
not do a good job, even if he had the necessary materials 
and formulae. 

Marble cases are made of slabs, cemented together. 
Many workmen use plaster of paris by merely mixing it 
with water, though we rather think it better to use glue in 
the mixing, as plaster so mixed will not set as quickly as 
that mixed with water. After the case is cemented with the 
plaster, the workman can go over the joint with a brush and 
water colors, and with a little care should be able to turn 
out a job in which the joint will not be noticeable. Another 
cement much used for marble is composed of the white of 
an egg mixed with freshly slaked lime, but it has the dis- 
advantage of setting very quickly. 

Marble case makers use a cement composed of tallow, 
brick dust, and resin melted together, and it sets as hard 
as stone at ordinary temperatures. 

It often happens that the marble case of a mantel clock 
is injured by some accident and its corners are generally 
the first to suffer. If the break is not so great as to war- 
rant a new case or a new part the repairer may make the 



THE MODERN CLOCK. 461 

case a little smaller or file until the edges are reproduced, 
after which the polish is restored. Proceed as follows : 

Take off from the damaged part as much as is necessary 
by means of a file, taking care however, not to alter the 
original shape of the case. Now grind off the piece worked 
with the file with a suitable piece of pumice stone and 
water and continue the grinding next with a water stone 
until all the scratches have disappeared, paying special at- 
tention to the corners and contours. After this has been 
done take a hard ball of linen, moisten it, and strew over 
it either tripoli or fine emery and proceed to polish the 
case with this. Finish the polishing with another linen 
ball, using on it still finer emery and rouge. Now dry the 
case and finish the polishing with a mixture of beeswax 
and oil of turpentine. This method may be employed for 
all kinds of marble, or onyx and alabaster cases. 

In cases where the fractures are very deep, so that the 
object cannot be made much smaller without ruining the 
shape, the damaged parts may be filled with a cement, pre- 
pared from finely powdered marble dust and a little isin- 
glass and water, or fish glue wall answer very well. Stir 
this into a thick paste, which fill into the deep places and 
permit to dry ; after drying, correct the shape and polish 
as described. 

If the pieces which have been broken off are at hand 
they may be cemented in place again. Wet the pieces with 
a solution of water and silicate of potash, insert them in 
place and let them dry for forty-eight hours. If the case 
is made of white marble use the white of an egg and a 
little Vienna lime, or common lime will answer. 

To Polish Marble Clock Cases. — It frequently be- 
comes the duty of the repairer to restore and polish marble 
clock cases, and we would recommend him to make a thin 
paste of the best beeswax and spirits of turpentine, clean 
the case well from dust, etc., then slightly cover it with 



462 THE MODERN CLOCK. 

the paste, and with a handful of clean cotton, rub it well, 
using abundant friction, finish off with a clean old linen 
rag, which will produce a brilliant black polish. For light 
colored marble cases, mix quicklime with strong soda water, 
and cover the marble with a thick coating. Glean off after 
twenty-four hours, and polish well with fine putty powder. 
To Remove Oil Spots From Marble. — Oil spots, if not 
too old, are easily removed from marble by repeatedly cov- 
ering them with a paste of calcined magnesia and benzine, 
and brushing off the magnesia after the dissipation of the 
oil; this may have to be repeated several times. Another 
recipe reads as follows : Slaked lime is mixed with a strong 
soap solution, to the consistency of cream; this is placed 
upon the oil spot, -and repeated until it has disappeared. In 
place of this mixture, another one may be used, consisting 
of an ox gall, 125 grains of soapmaker's waste lye and 62^ 
grams of turpentine, with pipe clay, to the consistency of 
dough. 

Cutting Clock Glasses. — You will sometimes want a 
new glass for a clock. I get a lot of old 5x7 negatives and 
scald the film off in plain hot water, rinse well and dry. 
Now I lay my clock bezel on a piece of paper and trace 
around with a pencil, inside measure. Now remove the 
bezel and trace another circle around the outside of this 
circle about one-eighth inch. Now, lay the paper on a 
good, solid, smooth surface, glass on top, and with a com- 
mon wheel glass-cutter follow around the outside line, free 
handed, understand. The paper with marked circle on is 
under the glass, and you can see right through the glass 
where to follow with the cutter. Now cut the margins of 
glass so as to roughly break out to one-half inch of your 
circle cut, running the cuts out on the side, then carefully 
break out. 



CHAPTER XXIV. 

SOME HINTS ON MAKING A REGULATOR. 

Of all the instruments used by a watchmaker in the 
prosecution of his business, there is probably none more 
iniportant than his regulator. Its purpose is to divide time 
into seconds, and it is the standard by which the practical 
results of his labors are tested ; the guide which all the 
other time-keepers in his possession are made to follow and 
the arbitrator which settles all disputes regarding the per- 
formance of his watches. 

No regulator has yet been constructed that contains with- 
in itself every element for producing absolutely accurate 
time-keeping. At intervals they must all be corrected from 
some external source, such as comparison with another 
time-keeper, the error of which is known, or by the motion 
of the heavenly bodies, when instruments for that purpose 
are available. Before beginning to make a regulator, the 
prudent watchmaker will first reflect on the various plans of 
constructing all the various details of an accurate time- 
keeper, and select the plan which, in his opinion, or in the 
opinion of those whom he may consult on the subject, will 
best accomplish the object he has in view. 

In former 3-ears a regulator case was made with the sole 
object of accommodating the requirements of the regulator, 
and every detail in the construction of the case was made 
subservient to the necessities of the clock. The plain, well- 
made cases of former years are now almost discarded for 
those of more pretentious design. If the general change in 
the public taste demands so much display, there can be no 
objection. It is perfectly harmless to the clock, if the de- 

463 



464 THE MODERN CLOCK. 

signers and makers of the cases would only remember that 
narrow waists or narrow necks on a case, although part of 
an elegant design, do not afford the necessary room for the 
weight and freedom of the pendulum; that the doors and 
other openings in the case must be constructed with a view 
to exclude dust ; and that the back should be made of thick, 
well-seasoned hardwood, such as oak or maple, so as to 
afford the means of obtaining as firm a support for the pen- 
dulum as possible. 

When a regulator case is known to have been made by an 
inexperienced person, which sometimes happens, or when 
we already have a case, it is always the safest course for 
those who make the clock to examine the case personally 
and see the exact accommodation there is for the clock. 
Sometimes, when we know beforehand, we can, without 
violating any principle, vary the construction a little, so as 
to make the weight clear the woodwork of the inside of the 
case, and in other respects complete the regulator in a more 
workmanlike manner by making the necessary alterations 
in the clock at the beginning of its construction, instead of 
after it has been once finished agreeably to some stereotyped 
arrangement. 

The arrangement of the mechanism of an ordinary regu- 
lator is a simple operation compared with some other 
horological instruments of a more complex character. We 
are not limited in room to the same extent as in a watch, 
and the parts being few in number a regulator is m.ore 
easily planned than timekeepers having striking or auto- 
matic mechanism for other purposes combined with them; 
yet it often happens that the inexperienced make serious 
blunders in planning a regulator, and, as the clock ap- 
proaches completion, many errors make themselves visible, 
which might have been avoided by the exercise of a little 
more forethought. It may be that, when the dial is being 
engraved, the circles do not come in the right position, or 
the weight comes too close to the pendulum, or the case. 



THE MODERN CLOCK. 46s 

or the cord comes against a pillar, or other faults of greater 
or less importance appear, all of which might have been ob- 
viated by taking a more comprehensive view of the subject 
before beginning to make the clock. The best way to do 
this is to draw a plan and side and front elevations to a 
scale. 




Fig. 152 

The position which the barrel and great wheel should 
occupy is worthy of serious consideration. In most of the 
cheap regulators, as well as in a few of a more expensive 
order, the barrel is placed in a direct line below the center 
wheel, as is shown in Fig. 152. This arrangement admits 
of a very compact movement, and it also allows the weight 
to hang exactly in the center of the case, which some think 



466 THE MODERN CLOCK. 

looks better than when it hangs at the side, especially when 
there is a glass door in the body of the case. But while a 
weight hanging in the center of a case may be more pleas- 
ing to the eye than when it hangs at the side, this is an in- 
stance where looks can, with great propriety, be sacrificed 
for utility, because when the weight hangs in the center it 
comes too close to the pendulum, and is very liable to dis- 
turb its motion. In proof of this statement, let any reader 
who has a regulator with a light pendulum and a com- 
paratively large weight hanging in front of it, closely watch 
the length of the arc the pendulum vibrates when the weight 
is newly wound up and when it is down opposite the pen- 
dulum ball, and he w411 observe that the length of vibration 
of the pendulum varies from five to fifteen minutes of arc, 
according to the position in which the weight is placed ; 
that the pendulum will vibrate larger arcs when the weight 
is above or below the ball than when it is opposite it ; and 
if the clock has a tendency to stop from any cause, that it 
will generally do so more readily when the weight is op- 
posite the pendulum ball than when it is in any other posi- 
tion. For this reason I would dispense with the symetrical 
looks of the weight hanging in the center of the case, wdiich, 
after all, is only a matter of taste, and construct the move- 
ment so that the weight will hang at the side, and as, far 
away from the pendulum as possible. 

Fig. 153 is intended to represent the effect which plac- 
ing the barrel at either side has on throwing the w^eight 
away from the pendulum. A is the center wheel ; B and C 
are the great wheels and barrels with weights hanging from 
them; D is the pendulum. It will be noticed by the dia- 
gram that the weight at the left of the pendulum is exactly 
the diameter of the barrel farther away from the pendulum 
than the weight on the right. On close inspection it will 
also be observed that on the barrel C the force of the weight 
is applied between the axis of the barrel and the teeth of 
the wheel, while on the barrel B the axis of the barrel lies 



THE MODERN CLOCK. 



467 



between the point where the force is appHed and the point 
where the teeth act on the pinion ; consequently a httle more 
of the effective force of the weight is consumed by the 
extra amount of pressure and friction on the pivots of the 
barrel B than there is in C. 

Notwithstanding this disadvantage, I would for a regu- 
lator recommend the barrel to be placed at the left side of 




,. Fig. 153 

the center wheel, because the weight may thereby be led a 
sufficient distance from the pendulum in a simple manner. 
If we place the barrel at the right, and thereby secure the 
greatest effective force of the weight, and then lead the 
weight to the side by a pulley, we will lose a great deal 
more by the friction of the pulley than we gain by the 
proper application of the weight. 

In a regulator with a Graham escapement but little force 
is required to keep it going, and there is usually accommo- 



468 THE MODERN CLOCK. 

dation for an abundance of power ; therefore we cannot use 
a little of this superabundant available force to better ad- 
vantage than by placing the barrel at the left side of the 
clock, and thereby throw the weight a sufficient distance 
from the pendulum in the simplest manner. 

The escapement we assume to be the old dead beat, as for 
tim.e-keeping it is equal to a gravity escapement while pos- 
sessing advantages undesirable to sacrifice for a doubtful 
improvement. The advantages it possesses over any form 
of gravity escapement are : it has fewer pieces and not so 
many wheels ; it takes very much less power to drive ; is not 
liable to fail in action while winding, if the maintaining 
power should be rather weak; while for counting, seconds 
and estimating fractions, its clear, definite, and equable beat 
has great superiority over the complication of noises made 
by a gravity escapement. 

Full directions for making this and other escapements 
have already been given, but in a regulator there are some 
considerations which will not be encountered in connection 
with the escapements of ordinary clocks, where fine time- 
keeping is not expected. We have previously stated that 
the center of suspension of the pendulum should be exactly 
in line with the axis of the escapement and we will now 
endeavor to state plainly how important this Is in a fine 
clock and the reasons for it. Mr. Charles Frodsham, the 
noted English chronomiCter maker, has conducted a series of 
careful experiments and the results were communicated in 
a report to the British Horological Society, as follov/s : 

When we talk of detached escapements, or any escape- 
ment applied to a pendulum, it is necessary to bear in mind 
that there is always one-third at the least of the pendulum's 
vibration during which the arc of escapement is intimately 
mixed up with the vibration, either in locking, unlocking, 
or in giving impulse; therefore, whatever inherent faults 
any escapement may possess are constantly mixed up in the 
result; the words ''detached escapement" can hardly be ap- 



THE IVODERN CLOCK 469 

plied when the entire arc of vibration is only two degrees ; 
or, in other words, what part of the vibration is left with- 
out the influence of the escapement? — at most one degree. 
In chronometers the arc of vibration is from ten to fifteen 
times greater than the arc of escapement. 

The dead-beat escapement has been accused of interfer- 
ing with the natural isochronism of the pendulum by its 
extreme friction on the circular rests, crutch, and difficulty 
of unlocking, etc., all of which we shall show is only so 
when improperly made. 

When the dead-beat escapement has been mathematically 
constructed, and is strictly correct in all its bearings, its vi- 
brations are found to be isochronous for arcs of different 
extent from 0.75 of a degree to 2.50 degrees ; injurious 
friction does not then exist; the run up on the locking has 
no influence, nor is there any friction at the crutch ; oil is 
not absolutely necessary, except at the pivots; and there 
is no unlocking resistance nor any inclination to repel or 
attract the wheel at its lockings. 

The general mode of making this escapement is very de- 
fective and indefinite, and entirely destroys the naturally 
isochronous vibration of the pendulum. 

The following is the usual rate of the same pendulum's 
performance in the different arcs of vibration with an 
escapement as generally constructed after empirical rules : 

Arc of vibration 3° rate per diem 9.0 seconds. 

Arc of vibration 2^° rate per diem 6.0 seconds. 

Arc of vibration 2° rate per diem 3.5 seconds. 

Arc of vibration ij4° rate per diem 1.5 seconds. 

Arc of vibration 1° rate per diem 0.0 seconds. 

Thus for a change of vibration of 1°, we have a daily er- 
ror of 3.5. No change of suspending spring will alter in- 
herent mechanical errors destructive of the laws of motion. 
With clocks made in the usual manner, whether you apply 
a long or short spring, strong or weak, broad or narrow, 



4.70 THE MODERN CLOCK. 

you will not remove one fraction of the error ; so the sooner 
the fallacy of relying upon .the suspending spring to cure 
mechanical errors is exploded the better. 

That the suspending spring plays a most important part 
must be admitted, since, when suspended by a spring, a 
pendulum is kept in motion by a few grains only, whereas, 
if supported on ordinary pivots, 200 lbs. weight would not 
drive it 2' beyond its arc of escapement, so great would be 
the friction at the point of suspension. 

The conditions on which alone the vibrations of the pen- 
dulum will be isochronous are the following: 

1. That the pendulum be at time with and without the 
clock, in which state it is isochronous "suspended by a 
spring." 

2. That the crutch and pallets shall each travel at the 
same precise angular velocity as the pendulum, which can 
only happen when the arc ^ach is to describe is in direct 
proportion to its distance from the center of motion, that 
is, from the pallet axis. 

3. That the angular force communicated by the crutch 
to the pendulum shall be equal on both sides of the quiescent 
point; or, in other. words, that the lead of each pallet shall 
be of the same precise amount. 

4. That any number of degrees marked by the crutch or 
pallets shall correspond with the same number of degrees 
shown by the lead of the pendulum, as marked by the index 
on the degree plate. 

5. That the various vibrations of the pendulum be 
driven by a motive weight in strict accordance with the 
theoretical law ; that is, if a 5-lb. weight cause the pendulum 
to double its arc of escapement of 1°, and consequently 
drive it 2°, all the intermediate arcs of vibration shall in 
practice accord with the theory of increasing or diminishing 
their arcs in the ratio of the square roots of the motive 
weight. 



THE MODERN CLOCK. 47I 

To accomplish the foregoing conditions, there is but one 
fixed point or Hne of distance between the axis of the 
escape wheel and that of the pallet, and that depends upon 
the number of teeth embraced by the pallets and only one 
point in which the pallet axis can be placed from which the 
several lines of the escapement can be correctly traced and 
properly constructed with equal angles, and equal rectangu- 
lar lockings on both sides, so that each part travels with 
the same degree of angular velocity, which are the three 
essential points of the escapement. 

Much difference of opinion has been expressed upon the 
construction of the pallets, as to whether the lockings or 
circular rests should be at equal distances from the pallet 
axis, with arms and impulse planes of unequal length, or 
at unequal distances from the pallet axis, with arms and im- 
pulse planes of equal length. In the latter case the locking 
on one side is three degrees above, and on the other three 
degrees below the rectangle, whereas in the former the tooth 
on both sides reposes at right angles to the line of pressure; 
but the length of the impulse planes is unequal. When an 
escapement is correctly made upon either plan, the results 
are very similar. 

It is possible to obtain equal angles by a false center of 
motion or pallet axis ; but then the arcs of repose will not 
be equal. This, however, is not of so much consequence as 
that of having destroyed the conditions Nos. 2, 3, 4; for 
even at correct centers, if the angles are not drawn off cor- 
rectly by the protractor, and precisely equal to each other, 
the isochronous vibrations of the pendulum will be destroy- 
ed, and unequal arcs will no longer be performed in equal 
times ; the quiescent point is not the center of the vibration, 
except when the driving forces are equal on both sides of 
the natural quiescent point of the pendulum at rest. 

Now this is the very pith of the subject, and which few- 
would be inclined to look for with any hope of finding in 



472 THE MODERN CLOCK. 

it the solution of this important question, the isochronism 
of the pendulum. 

- One would naturally suppose that unequal arcs on the 
two sides of the vertical lines would not seriously affect the 
rate of the clock, but would be equal and contrary, and con- 
sequently a balance of errors, and so they probably are for 
the same fixed vibration, but not for any other; because 
dififerent angles are driven with different velocities, the 
short angle has a quicker rate of motion than the long. 
Five pounds motive weight will multiply three times the 
pendulum's vibration over an arc of escapement of 0.75°; 
but the same pendulum, with an arc of escapement of 1°, 
would require 11.20 lbs. to treble its vibration; the times of 
the vibration vary in the same ratio as the sum of the 
squares of the differences of the angles of each pallet, com- 
pared with the spaces passed over. 

From this it will be seen that the exact bending point of 
the pendulum spring should be opposite the axis of the 
fork arbor when regulating the clock and this may have 
to be determined by trial, raising or lowering the plates by 
screws in the arms of the suspending brackets until the 
proper position is found, when the movement may be 
clamped firmly in position by the binding screws, see Fig. 

158. 

On common clocks the crutch is simply riveted on its 
collet and bent as required to set the clock in beat, but for 
a first-class clock a more refined arrangement is usually 
adopted. There are other plans, but perhaps none so thor- 
oughly sound and convenient as the following. The crutch 
itself is made of a piece of flat steel cut away so as to leave 
a round boss at the bottom for the fork, and a round boss 
at the top to fit on a collet on the pallet arbor, a part pro- 
jecting above to be embraced between a pair of opposing 
screws. On the collet is fixed a thin brass plate with two 
lugs projecting backwards from the frame, these lugs be- 
ing drilled and tapped to receive the opposing screws in a 



THE MODERN CLOCK. 473 

line. The boss of the crutch Hes flat against this plate, and 
is held up to it by, a removable collet. The collet may be 
pinned across or fitted keyhole fashion, in either case so as 
to hold the crutch firmly, allowing it to move with a little 
stiffness under the influence of the screws. With this ar- 
rangement the adjustment to beat may be made with the 
utmost delicacy by slacking one screw and advancing the 
other, taking care that in the end they are well set home so 
as to make the crutch practically all one piece with the 
arbor. Milled heads are most convenient for these screws, 
and being placed at the top they are easily got at. The 
crutch should always be fitted with a fork to embrace the 
pendulum rod, as this ensures the impulse being given di- 
rectly through the center, and with the same object the act- 
ing sides of the fork should be truly square to the frame. 
A slot in the pendulum rod with a pin acting in it is never 
so sure of being correct, as, although the surfaces may be 
rounded, it is very unlikely that the points*of contact will 
be truly in the plane of the axis of the rod. The slightest 
error in this respect will tend to cause wobbling of the bob, 
although, to avoid this, great attention must also be given 
to the suspension spring, the pin on which it hangs, and the 
pin and the hole at the top of the pendulum rod. All these 
points must be in a true line, and the spring symmetrical on 
both sides of the line in order that the impulse may be given 
exactly opposite the center of the mass, otherwise wobbling 
must occur, although perhaps of an amount so small as to 
be difficult of detection, and this is not a matter" of small im- 
portance, as it has an efifect on the rate which could be 
mathematically demonstrated. 

The frames of many regulators are made too large and 
heavy. In some cases there may be good reasons for mak- 
ing them large and heavy, but in most instances, and espe- 
cially when the pendulum is not suspended from the move- 
ment, it would be much better to make the frames lighter 
than we frequently find them. Very large frames present 



474 THE MODERN CLOCK. 

a massive appearance, and convey an idea of strength alto- 
gether out of proportion to the work a regulator is required 
to perform. They are more difficult and more expensive to 
make than lighter ones, and after they are made they are 
more troublesome to handle, and the pivots of the pinions 
are in greater danger of being broken when the clock is be- 
ing put together than when they are moderately light. 

In a clock such as we have under consideration, where 
the frame is not to be used as a support for the pendulum, 
but simply to contain the various parts which constitute the 
movement, the thickness of the frames may with propriety 
be determined on the basis of the diameter of the majority 
of the pivots which work into the holes of the frames. The 
length of the bearing surface of a pivot will, according to 
circumstances, vary from one to two and a half times the 
diameter of the pivot. The majority of the pivots of our 
regulator will not be more than .05 or .06 of an inch in 
diameter; consequently a frame 0.15 of an inch thick will 
allow a sufficient length of bearing for the greater portion 
of the pivots, and will also allow for countersinks to be 
made for the purpose of holding the oil. If thin plates are 
used one or two of the larger pivots should be run in bushes 
placed in the frame, as described in Fig. 155. 

The length and breadth of the frame, and also its shape, 
should be determined solely on the basis of utility. There 
can be no better shape for the purpose of a regulator than 
a plain oblong, without any attempt whatever at ornament. 
For our regulator a frame nine inches long and seven inches 
broad will allow ample accommodation for everything, as 
may be seen on referring to Fig. 157. 

The plates are made of various alloys : cast-brass, nickel- 
silver, and hard-rolled sheet-brass. It is difficult to make 
plates of cast-brass which would be even, free from specks, 
etc., but cast plates may very well be made of ornamental 
patterns and bushings of brass rod inserted, or they may 
be jeweled as shown in Figs. 154, 155, 156. Nickel, or 



THE MODERN CLOCK, 



475 



German silver, makes a fine plate, but it is difficult to drill 
the small holes through plates of four-tenths of an inch in 
thickness, on account of the peculiar toughness of the metal, 
so that bushings are necessary. The best material where 
the holes are to be In the plates Is fine, hard-rolled sheet 
brass; it should have about 4 oz. of lead to the 100 lbs., 
which will make it "chip free," as clockmakers term it, 
rendering it easy to drill ; the metal is so fine and condensed 
to that extent by rolling, that the holes can be made with 
the greatest degree of perfection. The many improvements 
in tools and machinery have effected great changes and im- 
provements in clock-making. It once was quite a difficult 
task to drill the small holes in the plates with the ordinary 
drills and lathes ; now we lay the plates "after they are sold- 



I rniLiMK I 



^i^^ i A 



Fig. 154 

ered together at the edges (which is preferable to pinning)', 
on the table of an upright drill, and with one of the modern 
twist-drills the task Is rendered a very easy one. After the 
pivot-holes are drilled-, we run through from each side a 
round broach, finished lengthwise and hardened, which acts 
as a fine reamer, straightening and polishing the holes ex-' 
quisitely. A little oil should be used on the reamer to prevent 
sticking. The method of fitting up the pivot-holes invented 
by LeRoy, a French clockmaker of some note, is shown in 
Fig. 154. It is a sectional view of the plate at the pivot- 
hole. It will be observed that. Instead of countersinking 
for the oil, the reverse is the case. A is a hardened steel 
plate counterbored into the clock plate B, and held In its 
place by the screws. There should be a small space between 
the steel plate and the crown of the arch for the oil. After 
the clock has been put together it Is laid down on its face 



476 



THE MODERN CLOCK. 



or side, a drop of oil is put to the pivot end, and the steel 
plate immediately put on; and the oil will at once assume 
the- shape of the shaded spot in the drawing, being held in 
the position at the center of the pivot by capillary attraction, 
until it is exhausted by the pivots; the steel plates also 
govern the end play of the pinions. The pivot ends being 
allowed to touch the plates occasionally, the shoulders of the 
pinions are turned away into a curve, and, of course, do not 
bear against the plate, as in most clocks. 




Fig. 155 



Glass plates may be used instead of steel, or rose cut thin 
garnets, or sapphires, with the flat sides smoothly polished, 
may be bought of material dealers and set in bezels like a 
cap jewel. They are very hard and smooth for the pivot 




Fig. 156 



ends, and the state of the oil at the pivots can be seen at any 
time. Clocks fitted up in this manner have been running 
many years without oiling. 

When fitted up in this way the plates may be thicker. 
We have made the clock plates about four-tenths of an inch 
in thickness, which allows of counterboring, and admits of 
long bearings for the barrel arbor, which are so liable to be 
worn down in the holes by the weights ; and the pivots of 
the pinions, by being a little longer, do not materially in- 
crease the friction. 



THE MODERN CLOCK. 477 

In first-class clocks, when all the materials are as hard 
as possible, the wheels and pinions high numbered, the 
teeth, pinions, pivots, and holes smooth, true, and well pol- 
ished, the amount of wear Is very slight, especially if the 
driving weight has no useless excess. Yet there are ad- 
vantages in having some parts jeweled, such as the pallets 
and the four escapement holes. The cost of sufli jeweling 
is not an objection, while the diminished friction of the 
smooth, hard surfaces is worth the extra outlay. The holes 
can be set in the bushes described in Fig. 156, the end 
stones being cheap semi-precious stones, either rose cut or 
round. 

For jeweling the pallets, dovetailed slots may be made so 
that the stones will be of a wedge shape; there is no need 
for cutting the slots right through as in lever watch pallets. 
The stones will be held more firmly if shaped as wedges 
lying on a bed of the steel and exposing only the circular 
resting- curve and the driving face. The slots can be filed 
out and the stones ground on a copper lap to fit, fixed with 
shellac and pressed firmly home while warm. The grind- 
ing and polishin^^ of the acting suriaces are done exactly as 
described for hard steel, only using diamond powder instead 
of emery. The best stones are pale milky sapphires, such 
as are useless as gems, this kind of stone being the hardest. 

The holes may be much shorter when jeweled, as the 
amount of bearing surface required with stones is less 
than with brass; this results in less adhesion through the 
oil, and less variation of force through its changes of con- 
sistency. The 'scape wheel may also be thinner w^th similar 
results, and less weight to be moved besides. So the advan- 
tages of jeweling are worth consideration. 

It is important to finish the wheels and pinions before 
drilling any holes in the plates and then to definitely locate 
the holes after trial in the depthing tool. 

For the clockmaker's use the next in value to the wheel- 
cutting engine is a strong and rigid depthing tool, for it is 



478 THE MODERN CLOCK. 

by means of this instrument that the proper center distances 
of wheels and pinions can be ascertained, and all errors in 
sizes of wheels and pinions, and shapes of teeth, are at once 
detected before the holes are drilled in the plates. In fact, 
this tool becomes for the moment the clock itself ; and if 
the workman will consider that as the wheels and pinions 
perform fh the tool for the little time he is testing them, so 
they will continue to run during the life of the clock, he 
will not be too hasty in allowing wheels to go as correct 
when a hundredth of an inch larger or smaller, and another 
test, would, perhaps, make the pitching perfect. 

There are various kinds of depthing tools in use, but 
many of them are objectionable for the reason that the cen- 
ters are so long that the marking points on their outer ends, 
are too far from the point where the pitching or depthing 
is being tested, and the slightest error in the parallelism of 
these centers is, of course, multipHed by the distance, so 
that it m.ay be a serious difference. Having experienced 
some trouble from this cause, we made an instrument with 
very short centers, on the principle that the marking points, 
or centers, should be as near the testing place as possible. 
We succeeded in making one with a difference of only 
three-fourths of an inch, which was so exact that we had 
no further trouble. It was made on the Sector plan, but 
upright, so that the work under inspection, whether wheels 
and pinions, or escapements, could be observed closely, and 
with a glass, if necessary. 

It is very important that the posts or pillars and side- 
plates of clocks should be m.ade and put together in the 
most thorough manner ; the posts should be turned exact to 
length and have large shoulders, turned true, so that the 
plates, when put together without screws should fit accur- 
ately, for if they do not, when the screws are driven, some 
of the pivots will be cramped. We prefer iron for the 
posts, it being stiffer, and better retaining the screw threads 
in the ends, which in brass are liable to strip unless long 





I bc 



480 



THE MODERN CLOCK. 



and deep holes are tapped. Steel pillars should be blued 
after being finely finished, thus presenting a pleasing con- 
trast. The plate screws should also be of steel, with large 
flat heads, turned up true, and having a washer next to the 
plate. Brass pillars are favored by many and are easier 
turned in a small lathe, but they should be much larger 
than the steel ones. 

When the pillars are made of brass round rod of proper 
diameter is the best stock. If this cannot be procured, a 
pattern is turned from wood, and a little larger in every 
respect than the pillar is desired to be. If there is to be 
any ornament put on the pillar, it is never made on the pat- 
tern, because it makes it more difficult to cast, and besides, 
the ornamentation would all be spoiled in the hammering. 
The pattern must be turned smooth, and the finer it is the 
better w^ill be the casting. After the casting is received the 



":> 



Fig. 159 



first thing to be done is to hammer the brass, and then cen- 
ter the holes, because it will be seen from Fig. 159 that 
there are holes for screws at each end of the pillar. Holes 
of about .20 of an inch are then bored in the ends of the 
pillars, and should be deep, because deep holes do no harm 
and greatly facilitate the tapping for the screws. After the 
holes are tapped, run In a bottoming tap and then counter- 
sink them a little, to prevent the pillar from going out of 
truth in the turning. It will depend a great deal on the 
conveniences which belong to the lathe the pillars are turn- 
ed in as to how they will be held in the lathe and turned. 
If the holes in the ends of the pillars have been bored and 
tapped true, and if the lathe has no kind of a chuck or 
face plate with dogs, suitable for holding rods, the best 



THE MODERN CLOCK. 481 

way IS to catch a piece of stout steel wire in the chuck and 
turn it true, cut a true screw on it, and on this screw one 
end of the pillar, and run the other end in a male center. 
However, if the screws are not all perfectly true, and the 
centers of the lathe not perfectly in line, this plan will not 
work well, and it will be necessary to catch a carrier on to 
the pillar and turn it between two male centers. 

The dial feet are precisely the same as the pillars, only 
smaller. These dial feet are intended to be fastened in the 
frame by a screw, the same as the pillars ; but it will be ob- 
served that the screw which is intended to hold the dial on 
the pillar is smaller. The dial feet will be turned in precise- 
ly the same manner as the pillars. For finishing the plain 
surfaces of the pillars and dial feet, an old 6 or 7-inch 
smooth file makes a good tool The end of the file is ground 
flat, square or slightly rounded, and perfectly smooth. The 
smoother the cutting surface the smoother the work done 
by it will be. It is difficult to convey the idea to the inex- 
perienced how to use this tool successfully. In the first 
place, a good lathe is necessary, or at least one that allows 
the work to run free without any shake. In the second 
place, the tool must be ground perfectly square, that is, it is 
not to be ground at an angle like an ordinary cutting tool. 
Then the rest of the lathe must be smooth on the top, and 
the operator must have confidence in himself, because if he 
thinks that he cannot turn perfectly smooth, it will be a long 
time before he is able to do it. A tool for turning the 
rounded part of the pillar, if a pattern of this style is de- 
cided on, is made by boring a hole, the size of the desired 
curve, in an old file, or in a piece of flat steel, and smooth- 
ing the hole with a broach and then filing away the steel. 
The shoulders should be smooth and flat, or a very little 
undercut, and the ends of the pillars should be rounded as 
is shown in Fig. 159, because rounded points assist greatly 
in making the frames go on to the pillars sure and easy, 
and greatly lessen the danger of breaking a pivot when the 
clock is being put together. 



482 THE MODERN CLOCK. 

When a washer is used the points of the pillars project 
half the thickness of the washer through the frames, the 
hole in the washer being large enough to go on to the 
points of the pillars. 

Figure 160 is an outline of the cock required for the pal- 
let arbor, and the only cock that will be required for the 
regulator. It is customary, in some instances, to use a 
cock for the scape-wheel and also for the hour-wheel arbors, 




Fig. 160 

but for the scape-wheel arbor I consider that a cock should 
never be used when it can be avoided. The idea of using 
a cock for the scape-wheel arbor is to bring the shoulder 
of the pivot near to the dial and thereby make the small 
pivot that carries the seconds hand so much shorter; and 
so far this is good, but then the distance between the shoul- 
ders of the arbor being greater, when a cock is used the 
arbor is more liable to spring and cause the scape-wheel to 
impart an irregular force to the pendulum through the pal- 
lets. This is the reason why I prefer not to use a cock 
except when the design of the case is such that long dial 
feet are necessary,' and renders the use of a cock indispen- 
sable. In the present instance, however, the dial feet are 
no longer than is just necessary to allow for a winding 
square on the barrel arbor, and therefore a cock for the 
scape wheel is superfluous. It is better to use a long light 
socket for the seconds hand than put a cock on the scape- 
wheel arbor in ordinary cases. Except for the purpose of 
uniformity a cock on the hour wheel is always superfluous, 
although its presence is comparatively harmless. The front 
pivot of the hour-wheel axis can always be left thick and 



THE MODERN CLOCK. 483 

Strong enough should the design of the case require the dial 
feet to be extra long. 

For the pallet arbor, however, a cock is always necessary, 
and it should always be made high enough to allow the 
back fork to be brought as near to the pendulum as possi- 
ble, so as to prevent any possibility of its twisting when 
the power is being communicated from the pallets to the 
pendulum. This cock should be made about the same thick- 
ness as the frames, and about half an inch broad. ]\Iake the 
pattern out of a piece of hard wood, either in one solid 
piece or by fastening a number of pieces together. The 
pattern should be made a little heavier than the cock is re- 
quired to be when finished, and it should also be made 
slightly bevelled to allow it to be easily drawn from the 
sand when preparing the mould for casting. After it is 
cast the brass should be hammered carefully, and then filed 
square, flat, and smooth. 

Screws are better and cheaper when purchased, but they 
may be made of steel or brass rod by any workman who is 
provided with a set of fine taps and dies. If purchased thev 
should be hardened, polished and blued before using them 
in the regulator. The threads of screws vary in proportion 
to the size of the screw and the material from which it is 
made. A screw with from 32 to 40 turns to the inch, and a 
thread of the same shape as the fine dies for sale in the tool 
shops make, is well adapted for the large screws in a regu- 
lator. However, it is not threads of the screws I desire to 
call attention to so much, although it must be admitted that 
the threads are of primary importance. It is the shape of 
the heads and the points which is too often neglected. 

A thread, or a thread and a half, cut down on the point 
of a screw, will allow it to enter easier than when the point 
is flat, round, or shaped like a center. This is not a new 
idea for making the points of screws, but the plan is either 
not known to many, or it is not practiced to the extent it 
ought to be. 



484 THE MODERN CLOCK. 

The shape of the head of a screw should also always be 
based on utility, and the shape that will admit of a slit into 
it that will wear well should be selected. A round head 
ought never to be used, because a head of thit shape does 
not present the same amount of surface to the screwdriver 
that a square head does. It is the extreme end of the slit 
that is most effective, and in round-headed screws this part 
is cut away and the value of the head for wearing by the 
use of the screwdriver is the same as if the head of the 
screw was so much smaller. A chamfered head may suit 
the tastes of some people better than a perfectly flat head, 
but in a head of this shape the slit must be cut deeper than 
in a square head, because the chamfered part of the head is 
of little or no use for the screwdriver to act against. The 
slits should always be cut carefully in the center of the head 
and the sides of the slit filed perfectly flat with a thin file 
and the slight burr filed off the edge to prevent the top of 
the head getting bruised by the action of the screwdriver. 
The shape of the slit which is best adapted for wearing is 
one slightly tapered, with a round bottom. The round bot- 
tom gives greater strength to the head, and prevents the 
heads of small screws from splitting. 

I have dwelt at some length on these little details because 
a proper attention to them goes a long way in the making 
of a clock in a workmanlike manner, and it is desirable that 
the practical details should be as minute as possible. 

The construction of the barrel is a subject which requires 
a greater amount of consideration than is sometimes be- 
stowed upon it. We often meet with regulator barrels 
which have considerable more brass put into them than is 
necessary. The value of this extra metal is of little or no 
consequence. It is the unnecessary pressure the weight of 
it causes on the barrel pivots, and the consequent increase 
of friction, which is objectionable. For this reason the 
weight of the barrel, as v^ell as the weight of every other 
part of the clock that moves on pivots, should be made no 



THE MODERN CLOCK, 



485 



heavier than is absohitely necessary to secure the required 
amount of strength. In every, instance, except when the 
diameter is required to be very small, the barrel should be 
made of a piece of thin brass tubing with two ends of cast 
brass fastened into it. 

Figure 161 is a sectional view of the ends of a barrel; 
the diagram on the right is the end where the great wheels 
rest against, and the one on the left is the other end. The 
insides of both these ends are precisely the same, but the 
outsides differ a little. It will be observed that there is a 



Fig. 161 



little projection near the hole on the outside of the front 
end. This projection is left with the view of making the 
hole in the center longer, and thereby causing this end to 
take a firmer hold on the barrel arbor. The back end, or 
the end that the great wh'eels rest against, and where the 
ratchet teeth are cut, is shaped precisely like the diagram 
on the right of Fig. 161. If you cannot get brass plate of 
sufficient thickness for the ends of the barrel they must be 
cast. 

The patterns for these barrel ends should be made with- 
out any hole in the center, and in every way heavier and 
thicker than they are to be when finished, because it is diffi- 
cult to obtain good and solid castings when the patterns are 
made thin, although it is by no means impossible to make 
them so. Like all brass castings used for the clockmaker's 
purpose, they should be carefully hammered, and, although 
these pieces are of an Irregular shape, they can be easily 



486 THE MODERN CLOCK. 

hammered regularly with the aid of narrow-faced hammers 
or punches, and with the exercise of a little patience. After 
hammering, the castings should be placed on a face plate 
in the lathe, and the tube which is to form the top part of 
the barrel fitted easy and without shake on to the flanges 
and the other parts of the castings turned down to the re- 
quired thickness, and a hole a little less than 0.3 of an inch 
diameter bored in the center of each before it is removed 
from the face plate. The tube which is to form the top of 
the barrel should be no heavier than is just necessary to cut 
a groove for the cord, and for this regulator it should be 1.5 
inch diameter outside measurement, 1.5 inch long, and turn- 
ed perfectly true on the ends. 

The hole in the front end of the barrel, which is the end 
nearest to the dial, should be broached a little from the in- 
side, and the other end broached a little larger from the out- 
side. The reason for broaching the holes in this manner is 
to cause the thickest part of the barrel arbor to be at the 
place where the great wheels work, because, in making a 
barrel for a regulator, it will generally be found that the 
arbor requires to be thickest in this particular place. The 
arbor should be made from a piece of fine cast steel a little 
more than 0.3 of an inch thick, and not less than four inches 
long. It is always well to have the steel long enough. This 
steel should be carefully centered and turned true, and of 
the same size and taper as the holes in the barrel ends. It 
is not necessary that the barrel arbor should be hardened 
and tempered, except on special occasions. In most cases 
it will last as long as any other part of the clock if it is left 
soft, and it is much easier to make when soft. Before fit- 
ting the arbor to the barrel ends it is well to place the ends 
into the tube that is to form the top of the barrel, because 
a better fit can be made in this way than when each is fitted 
separately. When the arbor has been fitted, a good and 
convenient way of fastening it together is, to use soft solder. 
It can be easily heated to the required degree of heat with 



THE MODERN CLOCK. 487 

the blow-pipe. A very little solder is sufficient for the pur- 
pose, and if the joints have been well fitted the solder will 
not show when the work is finished. Care should be taken 
to notice that the solder adheres to the arbors properly. 
Perhaps it would be well to mention here that, should the 
clockmaker not have access to a cutting engine with con- 
veniences attached to it for cutting the barrel ratchet after 
the barrel has been put together, the ratchet should be cut 
first. 

When the different pieces which constitute a barrel have 
been fastened together the brass work has next to be turned 
true, and the grooves cut for the cord to run in. It is best 
not to turn anything off the arbor till the grooves are cut, 
because they are usually cut smoother v/hen the arbor is 
strong. The most important points to notice when turning 
a barrel is to be sure that the top is of equal diameter from 
the one end to the other, and that the bearing wdiere the 
great wheels rest against are perfectly true, because, if the 
top of a barrel is of unequal thickness, the weight will piill 
with unequal force as it runs down, and if the bearing on 
the end be out of truth the great w^heels will also be very 
liable to get out of truth, as their position on the barrel is 
altered by winding the clock up. 

The shape of the outside of the barrel ends, as is rep- 
resented in Fig. 161, will be found to be good and service- 
able. AA is the bearing for the great wheels to rest against ; 
BB is where the ratchet teeth are to be cut. There must 
be a little turned off the face of BB, as is shown in the dia- 
gram, so as to prevent the great wheel from rubbing on 
the teeth. The space between AA and the barrel arbor is 
turned smooth. 

Although it is by no means an absolute necessity to have 
a groove cut in the top of the barrel, yet it is extremely de- 
sirable that there should be one, so that the cord may al- 
ways be guided with certainty as the clock is w^ound up. It 
has long been a disputed question whether the cord should 



^SS UiE I.I ODE KM C1.0CK. 

be fastened at the front end of the barrel and wind towards 
the back, or whether it should be fastened at the back and 
wind towards the front. I am not aware that there is any 
violation of principle, so far as the regularity of the power 
is concerned, whether the cord runs one way or the other. 
I understand it to be solely a question of keeping the weight 
clear of the case and the pendulum ball. In ordinary con- 
structed regulator cases this object will be best attained by 
cutting the screw so that the cord can be fastened at the 
front of the barrel and wind towards the back; because in 
making it in this way, the weight is the length of the barrel 
farther away from the front of the case when it is wound 
up, and about the same distance farther away from the 
pendulum ball when it is nearly run down, than if the cord 
was fastened at the back end of the barrel and wound 
towards the front. The cutting of the groove is usually 
done in an ordinary screw cutting lathe. 

In making the pivots on a barrel it is the usual custom to 
make the back pivot smaller than the front one but, with 
all due respect for this time-honored custom, I would di- 
rect a little attention to the philosophy of continuing to 
make the barrel pivots of a regulator in this manner. Fric- 
tion varies with pressure ; a large pivot has a greater 
amount of friction than a smaller one, because the pressure 
on the sliding surface of the revolving body is farther away 
from the center of m.otion in one case than in the other. 
In regulators where the barrel pivots are of a different size, 
the effective force of the weight will vary slightly accord- 
ing as the weight is fully wound up or nearly run down. In 
one instance the pressure of the weight is more directly on 
the large pivot than it is on the smaller one; and in the 
other instance the pressure is more directly on the small 
pivot than it is on the larger one, and when the weight is 
half wound up,. or half run down,^ the pressure is equal on 
both pivots. 



THE MODERN CLOCK. 489 

In the center pinion and in some of the other arbors of a 
clock, it is sometimes necessary to make one pivot con- 
siderably larger than the other ; but in these cases 
the difference in the size of the pivots does not affect the 
regularity of the transmission of the power, because the 
pressure that turns the wheel is always at the same point. 
In a regulator barrel, however, the pressure of the cord and 
weight shifts gradually from one end of the barrel to the 
other, as the clock runs down, and when the pivots are of 
unequal thickness the power is transmitted nearly as ir- 
regular as if the top of the barrel was slightly conical and 
both pivots of the same size. For the above reason, I think, 
that it will be plain to all that in a fine clock both of the 
barrel pivots should be made of an equal diameter. The 
front pivot should be made no larger than is absolutely nec- 
essary for a winding square, and when we take the fact into 
consideration that a fine clock with a Graham escapement 
requires considerable less power to keep it in motion than 
an eight-day marine chronometer does, we may safely con- 
clude that the winding squares of many regulators of the 
Graham class might be made smaller. A pivot about 0.2 
of an inch will secure a sufficient amount of strength. 
For the reasons mentioned above, the back pivot should be 
exactly the same diameter, and although the effects of fric- 
tion will be slightly greater when both pivots are of an 
equal size, still the force of the weight will be transmitted 
more regularly, w^hich is the object aimed at. Where the 
plates are bushed a length of two to three diameters is long 
enough for the pivot holes. 

The stop works, maintaining powers and general ar- 
rangement of the great wheel, ratchets and clicks, have 
been so fully described and illustrated on pages 282 to 290, 
Figs. 83 to 87, that it would be useless duplication to re- 
peat them here, and the reader is therefore referred to those 
pages, for full particulars. This is also the case with the 
purely mechanical operations of cutting the w^heels and 



490 ThK MODERN CLOCK. 

pinions, hardening, polishing, staking, etc. ; all have been 
fully treated; but there are some further considerations 
which may be mentioned here. The practical value of mak- 
ing pinions with very high numbers is very much over- 
rated. I know of two clocks situated in the same building 
that are compared every other day by transit observation. 
They both have Graham escapements and mercurial pendu- 
lums, and are equally well fitted up, and as far as the eye 
can detect, they are about equally well made in all the essen- 
tial points, with only this difference : one clock has pinions 
of eight, and the other pinions of sixteen leaves, yet for two 
years one clock ran about equally as well as the other. In 
fact, if there was any difference, it was in favor of the clock 
with the eight-leaved pinions. In giving this example, I 
must not be understood to be placing little value on high- 
numbered pinions. I know that in some instances they can 
be used to advantage. The idea that I want to illustrate at 
present is, that it is not in this direction that we are to 
search for the means of improving the rates of regulators. 

A pinion as low as eleven leaves can be made so that the 
action of the tooth will begin at or beyond the line of cen- 
ters; but as eleven is an inconvenient number to use in 
clock-work, we may with great propriety decide upon 
twelve as being a sufficient number of leaves for all the 
pinions used in a regulator having a Graham escapement. 

In arranging the size of the wheels in a regulator, the 
diameters of the center and third wheels are determined by 
the distance between the center of the minute and the cen- 
ter of the seconds hand circle on the dial. As the dials of 
regulators are usually engraved after the dial plates have 
been fitted, and as the position of the holes in the dial for 
the center and scape wheel pivots to come through deter- 
mines the size of the seconds circle, it may be well to men- 
tion here that, for a twelve-inch dial, two and a half inches 
is a good distance for the center of the minute circle to be 
from the center of the seconds circle. Consequently the 



THE MODERN CLOCK. 49I 

center and third wheels must be made of such a diameter 
as will raise the scape wheel arbor two and a half inches 
from the center arbor, and the other wheels must be made 
proportionably larger, according to the number of teeth they 
contain. 

We all know what a difficult matter it is to make a cutter 
that will cut a tooth of the proper shape ; but when the cut- 
ter is once made and carefully used, we also know that it 
will cut or finish a great number of wheels without injury. 
For this reason, those who are contemplating making only 
one, or at most but a few regulators, will find the work will 
be greatly simplified by making the wheels of a diameter 
proportionate to the number of teeth they contain, and for 
all practical purposes the cutter that cuts or finishes the 
teeth of one wheel will be sufficiently accurate for the oth- 
ers. If we make all the pinions with the same number of 
leaves they will also all be nearly of the same diameter, and 
may be cut, or rather the cutting operation may without 
any great impropriety be finished with one cutter. 

An opinion prevails among a certain class of workmen 
that the teeth of the great wheel and leaves of the center 
pinion should be made larger and stronger than the other 
wheels and pinions, because there is a greater strain upon 
them than on the other. However reasonable this idea may 
seem, a little consideration will show that in the case of a 
regulator, with a Graham escapement, where so little mo- 
tive power is required to keep it in motion, an arrangement 
of this nature is altogether unnecessary. The smallest teeth 
ever used in any class of regulators are strong enough for 
the great wheel ; and if there be a greater amount of strain 
on the teeth of the great wheel in comparison with the teeth 
of the third wheel, for example, then make the great wheel 
itself proportionately thicker, as is usually done, according 
to the extra amount of strain that it is to bear. The teeth 
of wheels and the leaves of pinions wear more from imper- 
fect construction than from any want of a sufficient amount 
of metal in them. 



492 THE MODERN CLOCK. 

If we assume the distance between the center of the 
minute and the center of the seconds circle to be 2^ 
inches, and also assume that the clock will have a seconds 
pendulum, and all the pinions have 12 leaves, and the bar- 
rel make one turn in 12 hours, then^ the following is the 
diameter the wheels will require to be, so that the teeth 
may all be cut with one cutter, and also the number of 
teeth for each wheel: 

Great wheel 144 teeth. Diameter 3.40 inches for the pitch 
circumference. 

Hour wheel 144 teeth. Diameter 3.40 inches for the pitch 
circumference. 

Center wheel, 96 teeth. Diameter 2.26 inches for the pitch 
circumference. 

Third wheel 90 teeth. Diameter 2. 11 inches for the pitch 
circumference. 

Scape wheel 30 teeth. Diameter 1.75 inches for the pitch 
circumference. 

The number of arms or crosses to be put in a wheel is 
usually decided by the taste of the person making the clock. 
There is, however, another view of the subject, which I 
would like to mention. With the same weight of metal a 
wheel will be stronger with six arms than with four or five, 
and as lightness, combined with strength, should be the ob- 
ject aimed at in making wheels, I prefer six arms to four or 
five for the wheels of a regulator. 

Figs. 157 and 158 are front and side elevations of the 
proposed regulator m.ovement, showing the size and posi- 
tion of the wheels, the size of the frames, the positions of 
the pillars, dial feet, etc. The dotted large circular lines 
on Fig. 157 show the position the hour, minutes, and sec- 
onds circles will occupy on the dial. According to the ordi- 
nary rules of drawing, the dotted lines would infer that the 
movement is in front of the dial, and perhaps it may 
be necessary to explain that in the present instance these 



THE MODERN CLOCK. 493 

lines are made dotted solely with the view of making the 
diagram more distinct, and are not intended to represent 
the dial to be at the back of the movement. A is the barrel, 
B is the great wheel, which turns once in twelve hours; 
C is the hour wheel, which works into the great wheel, and 
also turns once in twelve hours ; D is the center wheel, 
which turns once in an hour, and carries the minute hand; 
E is the third wheel, and F is the scape wheel, which turns 
once in a minute and carries the seconds hand; G is the 
pallets ; H the pillars, and I is the dial feet ; J is the main- 
taining power click, and K shows the position of the cord. 
Neither the hour or great wheels project over the edge of 
the frame, and it will be observed that a clock of this ar- 
rangement is remarkable for its simplicity, having only four 
wheels and three pinions, with the addition of the scape 
wheel and the barrel ratchets. There are no motion or dial 
wheels, the wheel C turning once in 12 hours, carrying the 
hour hand. The size and shape of the frames and the posi- 
tion of the pillars, allows the dial feet to be placed so that 
the screws which hold the dial will appear in symmetrical 
positions on the dial. 

Formerly the term "astronomical" was applied to clocks 
which indicated the motions and times of the earth, moon, 
and other celestial bodies, but at present we may take it 
as indicating such as are used in astronomical ob- 
servatories. In all essential particulars they are the 
same as first class watchmakers' regulators, the most 
obvious departure being that the hour hand is made 
to revolve only once a day, the dial being divided into 
twenty-four hours. This only requires an intermediate 
wheel and pinion in the motion work, and, assuming the 
hour hand to be driven from the center arbor, there will be 
the usual hour and minute wheels and cannon pinion. The 
most suitable ratio for these are ^ and 1/6 = 1/24, and, 
as any numbers, being multiples, may be used, they may as 
well be selected so as to be cut with the same tools as the 



494 'T^E MODERN CLOCK. 

wheels of the train. Two pinions of 20 and wheels of 80 
and 120 suit very well ; 20 -f- 80 and 20 -f- 120 = 20/80 X 
20/120 = 400/9600 = 1/24, and the hands will both go in 
the same direction. 

Some astronomical clocks show mean solar, and others 
sidereal time; this requires no structural alteration, merely 
a little shortening of the pendulum in the latter case, which 
can be done with the regulating nut. 



LIST OF ILLUSTRATIONS. 



Addendum 202, 218, 220 

Angular Motion 103,112 

Automatic Pinion Cutter 245, 247 

Drill 249 

" Wheel and Pinion 
Cutter... 254 



Calendar, Simple 351 

" Perpetual 354, 356, 358 

Center Distances 105, 111, 202 

Chimes, Laying out - 

370, 421, 422, 423, 424, 425 

Chimes Westminster 372 

Click, Position of _..288 

Cock 482 

Compensated Rod, Steel and 

Zinc 42 

Counter-poising Hands... 443 

Count hook. Position of 305 

Count Wheel Striking Train 

302, 303, 311, 314, 315, 316, 322, 324 
Cuckoo Bellows and Pipe 328 

D 

Dedendum 202 

Dial Work 295 

Diameters of Wheels, Getting 196 

E 

Eight-day Count Wheel, Time 
and Striking Trains 299.. -.309 

Eight-day Snail Strike -342 

Electric Chimes... 

—.421,422, 423,424,425 

Electric Clocks, Pendulum 

Driven 377,379,381,382 

Electric Clocks, Weight 

Driven 394, 395, 396,398 

Epicycloid 206, 219, 239 



Escape Wheel, Cutting.. .122, 121 
" " Drawing to fit 

Pallets lao 

Escapement, Anchor 

— .142,144,145,146,147 
" Brocot's Visible 

127, 129 

" Cylinder.. 

164, 165, 166, 167, 177, 179, 181, V83 
Dead Beat 117, 118 

" Drum 148 

" Gravity 

152, 154, 157, 159, 161 

Pin 185, 194 

Pin Wheel 136, 137 

" Recoil 

142. 144, 145, 146, 147 
to draw the 114 

r 

Friction Springs 294 

G 

Grandfather clocks S52 

H 

Hypocycloid 206 

K 

Keyhole Plates 289 



Lever Escapement for Clocks 193 
Levers, the Elements of 99, 100, 101 

M 

Maintaining Powers 285, 286,287,291 



495 



496 



THE MODERN CLOCK, 



Pallets, Drawing 116 

Pendulum Brackets 32 

- " Mercurial 67, 71, 75 

" Torsion ....92, 93, 94, 95 

Oscillation of 10, 14, 21 

" Rieffler 50,75 

Perpetual Calendar Clocks.. 

354, 356,358 

" Brocot 

....360, 362, 363,364. 366 

Pinion Drill 251 

Pitch Diameter 202, 218, 219, 220, 239 

Plate, Jeweling .475, 476 

Posts - 480 

Precision Clock Room 453 



Q 



Quarter Chiming Snail Trains 341 
Quail and Cuckoo Train...322, 324 

Rack, Division of 335 



Regulator Trains 465, 467, 479 

Rounding Up Wheels 220, 224 

s 

Secondary Dials 4l6 

Self Winding Clocks.... 

—.400, 401, 404, 406, 408, 412 

Ship's Bell Train .314, 315, 316 

Slide Gauge Lathe 241 

" Tools 243 

Snail, Laying Out ...337 

" Striking Trains 

333,342,345, 346 

Suspension Springs 84 

Synchronizing Clocks 412,415 

w 

Wheel Cutting Engine 255 

Wiring Systems 386,388 

Wood Rod and Lead Bob 33 



Zinc Bob and Wood Rod^ 



.31 



INDEX. 



Addendum 202 

Air, Pressure of 20 

Aluminum, Compensation 

with 48 

Anchor Escapement 141 

Angular Measurement, Pecu- 
liarities of 102 

Apparent Time 348 

Arbors, Polishing Steel —232 

Straightening Bent -.231 

Arc of Escapment 93,109, 

115, 127, 138, 145, 153, 164, 186, 469 
Armatures, Adjustment of 389,409 

Astronomical Clocks 493 

•• Day 348 

Auxiliary "Weights, 37 

Balance, Vibrations of 180 

Banking... ..90, 156, 160, 170, 176 

Barometric Error 20 

Barrels—. 244,267,465,485 

" Chiming 370 

Batteries 380 

" Dating 392 

Grading .384 

Making... 383 

" Position of ..385 

" Wiring, Methods of 385 

Beat, to put a Clock in.. 89 

Bells .369 

•' Ships 315 

Brocot's Calendar 359 

" Visible Escapement 

127,128 

Bushing 476 



Cables, Clock 269 

•• Lengths of... 271 

Calculations of Weights 57 



Calendars 347 

Brocot's 359 

Gregorian ..349 

Julian 349 

" Perpetual 353 

*' Simple 350 

Carillons 372 

Case Friction -.. 448 

'* Temperature 450 

Cases 446 

Gilding 459 

Marble 460 

to Polish 461 

Polishing .. 457 

" Precision Clock 447 

Regulator 463 

" Restoring old ..455 

Cement for Marble 460 

for Dials 438 

Center Distances 110, 200 

" of Gravity 18 

of Oscillation 13 

Springs 96,294 

Chain Drives 271 

Cheap Clocks, to clean - 187 

Chime Barrels, to mark 371 

Chimes 339,370 

Cambridge 372 

Carillon 372 

Electric.-.: 420 

Tubular 374,422 

Circle, Pitch 202 

Circular Error 21 

Pitch 215 

Cleaning Cheap Clocks 187 

Clocks, Astronomical 493 

Cuckoo 319, 321 

'• Designing -8 

" Four-hundred day 91 



497 



498 



THE MODERN CLOCK. 



Clocks, Glass of.. - 4fi2 

Repeating ....332 

•' Room 452 

Cock ._. .-..482 

Collets..- .- 234 

Compensated Pendulum Rocts 40 

Rod, Flat .^1 

" Rods, Tubular. -48 

Compensation . 450 

Compensating Pendulums.... 23 

Bracket for 32 

Compensating Pendulums, 
Principles of Construc- 
tion 27 

Compensating Pendulums 

with shot ._ - 36 

Compensating Pendulums, 

Wood Rod and Lead Bob .... 32 
Compensation Pendulums, 

Wood Rod and Zinc Bob. -28 
Compensation Pendulums, 

Aluminum 48 

Cones, Rusting of 190 

Construction of Dials 426 

Contacts, Dial 423,425 

Electric ...396 

Contrate Wheel. ..- 171, 375 

Conversion, Table of 18 

Cords 2C8 

" Lengths of 270 

Count Hook ..301, 304, 310 

*• Wheel 301,304,315 

" '* Train 300 

Crown Wheel 171 

Crutches 87, 472 

Cuckoo, Adjustments of 326 

Bellows 328 

" Clock, Names of 

Parts 323 

" Motion Work 296 

Repairing .327 

Cutters for Clock Trains 196 

Setting 197 

Cycloid ...21 

Cylinder Clocks, Examina- 

tion of 171 

Cylinder, End Shake 170 

" Propor- 
tion of 149 

Side Shake 167 

•* Teeth, Shape of... .183 



Cylinders, Weight of 37 

D 

Day, Astronomical 348 

Sidereal... 318 

" Solar 348 

Dedendum 202 

Denison Escapment 150 

Depolarizers 3S1 

Depthing 200 

" Tool ...477 

Designing Clocks 8 

Detached Lever Escapement 184 

Dials, Construction of 426 

" Contacts.- 423,425 

" Enamel for .431 

" Phosphorescent ..437 

Repairing 432,438 

•' Secondary 417 

to Clean 436 

" " Silver 434 

" Varnish for... 438 

Distances, Center ...200 

Drawings, to read 98 

Draw of Teeth 191 

Drill, Pinion 249,251 

Drop... 1 107 

E 

Effect of Temperature 62 

Eight Day Trains 299 

Electric Chimes .420 

" Clocks 376 

" " Synchronizing 

400,413 

" Contacts 396 

Elements, Mechanical .98 

Enamel for Dials... 431 

End Shake, of Cylinder.. .170, 175 

End Stones .... 477 

Epicycloid 206 

Equation of Time ..365 

Error, Barometric 20 

" Circular 21 

" Temperature 22 

Escape Wheel, Sizes of 109, 

.-.133, 155, 164 
'• " To make.- 

109, 120, 135, 138, 
150,155,162,161 



THE MODERN CLOCK. 



499 



Escapement, Brocot's 127, 128 

Cylinder 163 

" Denison 150 

" Detached Lever 184 

Drum 148 

Graham 109 

Gravity 150,161 

•• LePaute's Pin 

Wheel 135 

Pin 185,193 

Recoil - lil 

" TodrawGrahamll3 

" Pin Wheel 138 
" Gravity -.152 
" Western Clock 

Mfg. Co 193 

Examination of Cylinders — 171 
Expansion of Metals 22 

F 

Fan 308,326 

Fly for Gravity Escapement--158 

Frames, Making.-- 261 

Thickness of 474 

Four-hundred Day Clocks 91 

Friction, Disengaging..-. 203 

" Engaging 203 

of Teeth... 132 

" Springs- 294 

G 

Gathering Pallet 338,344 

Gilding 459 

Gong Wires 369 

Graham Escapement 109,467 

Gravity, Center of 18 

" Escapement 150 

Gregorian Calendar 349 

H 

Half Hour Striking Work 

334,312,345 

Hammers ..367 

Hardening.. .198, 480, 482 

Springs .—368 

Tail 298,301 

Hands 439 

" Proportions of 440 

" To Balance 442 

•* To Blue 444 



Hour Rack 335 

" Snail - 296,334 

" Strike 342 

'• Wheel.- 96, 293, 2^r,. 325 

Ilypocycloid Curves 206 



Iron, Expansion of 57 

Information, Need for 3 

Isochronism 469 



Jeweling-. 475,477 

Jewels, Pallet 126 

Julian Calendar 349 



Lantern Pinions .-- 235 

Lathe, Slide Gauge—. 241, li43, 246 

Laws of Pendulums .^..11 

Lead 22,32 

Leap Year.. 349 

Length of Pivots.... ..199 

Lepaute's Escapement 135 

Leverage of Wheels 99 

Lift- 106 

Lifting Cam .-.301,331 

Piece ----331 

Planes 116 

Pins 186 

Lock 107 

Locking Hook 301 

Losing Time 192 

Lunation 365 

M 

Magnets, Arrangement of 

378, 386, 389, 395, 401, 406 

Mainsprings 272, 274, 277, 278, 

279, 280,281,282 

Breakage of 281 

Buckled 277 

" Cleaning 277 

Clock 288 

Coil Friction... -277 

Fuzee 279 

" Importance of 

Cleaning 274 

Length of 280 



500 



THE MODERN CLOCK. 



Mainsprings, Loss of Power. ..274 
" Maintaining 

Power.— 285,291 

Oiling 278 

" Stop Works 282 

Maintaining Powers 285 

Mean Apparent Time 348 

Mean Time ...348 

Measuring Wheels 195 

Measurement, Angular 102 

Mechanical Elements 98 

Mercurial Pendulums.— 53, 60, 09 
For Tow- 
er Clocks 65 

Mercury.. 53,56,66,70 

Metals, Expansion of 22 

Weight of 37 

Millimeters Compared with 

Inches 18 

Minute Jumpers _..-.. 417 

Wheels 96,293,296,325 

Month Clocks 260 

♦•' Sidereal 349 

" Synodic 350 

Moon, Phases of 365 

•• Train.... 365 

Motion Work 96, 293, 296, 325 

N 

Need for Information 3 

Numbers, Conversion of 201 

Nut, Rating 42,50,66 

o 

Oiling Cables - 269 

Oscillation, Center of 13 

Overbanking 90, 156, 160, 170, 176 



Pallet Jewels 126 

Pallets..l06, 115, 121, 126, 130, 135, 
-139, 141, 144, 149, 153, 186, 193, 470 

Pallets, To make 119, 126 

Pendulum, Isochronous 470 

Lengths, Table of 

10,16 

Rieffler 49, 75 

Rods 262 

" Compensated .40 

Comi)ensating 23 

Electric Driven... .376 



Pendulum, Laws of 11 

Mercurial 53,60,69 

" Sidereal 493 

" Torsion. ...91 

Perpetual Calendar E53 

Phases of the Moon .365 

Pillars, Making _ 240 

Pinion Drill, Atrtomalic--.249, 251 

Making 227,252 

" " Machine, Auto- 

matic -.245, 247 

Canon 293,294.295 

Depthing 206, 210, 217 

" Facing 233 

" Hardening 229 

" Lantern .235 

" Tempering 230 

*' To Draw. 206 

Pin Escapement -.. ..185.193 

" Wheels 297, 301, 327 

" •* Escapement.. 135 

To... 
Draw 138 

Pitch, Addendum 216 

" Circle 202 

•' Circular 215 

" Diametral 216 

Pivots 488 

" Length of 199 

" Proportions of 167,173,199,474 

'* Side Shake ...199 

Planes, Lifting 116 

Plates, Clock 198 

" Thickness of 474 

Poising Balance Staffs... 189,190 

Polishing Steel Arbors 232 

Posts, Clock ..478 

Power 264, 265, 266, 267 

" Maintaining 285 

Putting in Beat 89 

R 

Rack, Division of 335 

Striking Work 331 

Ratchet 288 

Rating Nut 42, 50, 66 

With Shot 90 

Reading Drawings 98 

Repeating Clocks 332 

Recoil Escapement 141 

Regulation 79 

Regulator Trains..- 492 



THE MODERN CLOCK. 



501 



Regulators, Making 463 

Repairing Dials 432,438 

Resistance Spools 368 

Rieffler Pendulum 49,75 

Rounding Up 174,221,223 

"Rules for 226 

Run 108 

Rusting of Cones 190 

S 

Screws, Clock 483 

Secondary Dials 417 

Self-winding Clocks 376 

Ship Bells, Striking 313 

Shot, Rating with •.SO 

Sidereal Day — -348 

Month 349 

Pendulums - 4S3 

Year —.349 

Side Shake, Cylinder —167 

" For Pivots 199 

Silvering Dials 434 

Simple Calendar 350 

Sizes of Teeth —.211,213,237 

" " Wheels... COl 

Slide Gauge Lathe 241,243,244 

Snail......... '^96, 33') 

" Division of 337 

" French System 342 

•• Quarter Striking Work. ..339 

" Striking Work .330,340 

Solar Day— - 348 

Sparking, to Prevent — 386 

Springs, Center 294 

Clock 273,288,307 

" Friction.. 294 

Hammer 368 

Main 272,273,274, 

.—277, 278, 279, 280, 282, 307 

Squares, Milling...... -..261 

Standards, Importance of 26 

Star Wheel 332,335 

Steel, Expansion of 57 

Stop Works 282 

Straightening Bent Arbors — 231 
Striking from Center Arbor. -.298 

To Correct 306,307 

'• ■ Trains.297, 308, 313, 323, 330 
" " Half Hour... 

...298, 308, 313 
" " Setting Up. - 

.-.-307, 310, 339 



Striking Trains, To Calculate. 297 

Rack 331 

Work, Repeating .. .332 

Snail 330,340 

Supports, Pendulum — 86 

Suspension 81, 93 

" Springs 82,93 

Synchronizing 400,413 

Synodic Month 350 

T 

Table, Lengths of Pendulum 

12,16,17,34,258 

" of Expansions 30 

" " Inches, Millimeters 

and French Lines. .18 

" " Time Trains 258, 

339, 340,492 

" " Weights and Metals.37 

Tangent 104 

Teeth, Friction of 132 

Shape of Cylinder 183 

" Shapes of.. 203 

Sizes of 2.1, 213,237 

Temperature, Effect of..- 62 

Error 22 

Tempering 229 

Time, Apparent 348 

" Equation of 365 

" Losing.. 192 

Mean... 348 

To Draw Anchor Escapement 

143, 145, 147 

Top Weights 39 

Torsion Pendulums 91 

Tower Clock, Cables .269 

" " Dials, Sizes of.. .426 
" " Gravity Escape- 
ment for 150 

Hands ..442 

" " Maintaining 

Powers.. -285, 291 
Motion Work--.-295 

" " Pendulums 65 

Stop Works 2S7 

*' " Suspension 65 

t< Time Trains 258 

Trains 330 

Electric 389 

Regulator 492 

" 'Table of 258 

" To Calculate— .257, 264, 297 



502 



THE MODERN CLOCK. 



Tropical Year 3*8 

Tubular Chimes 374, 422 

Turning Tools 481 

Y 

Varnish for Dials 438 

•* Remover .456 

Vibrations of Balance 180 

w 

Warning-. 306,312 

Pin 306,312 

Wheel 306,312 

Weight Cords 268 

Weight of Lead, Zinc and 

Cast Iron Cylinders 37 

Weights 265, 319 

" Auxiliary 37 

" Calculations of 27 

Top 39 



Wheel Contrate 171,375 

Crown 171 

Hour 296 

Cutting 254 

Leverage of 99 

Measuring 195 

Minute 96, 293, 296, 325 

Sizes of 201, 490 

Stamping 256 

Star—-.-. 332, 335 

Stretching 226 

Wires, Gong 369 



Y%ar , I 348 

" Leap 349 

" Sidereal ..349 

" Tropical.. 348 

z 

Zinc 54 



.-^xC^t^-C--^- 




BIG BEN Is the first and 
only alarm sold exclu- 
sively to jewelers. He 
is without exception the finest 
sleepmeter made — the best 
looking, the best built, the 
best running. 

Big Ben is a beautiful thin 
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inches tall and mounted in a 
reinforced triple plated case. 
He is fitted with big strong 
easy winding keys, clean cut 
heavy hands and a large open 
winsome dial, distinctly visible 
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Big Ben rings just when you 



want and either way you want, 
intermittently for fifteen min- 
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and he rings with a jolly full- 
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drowsiest sleeper. 

Big Ben is rigidly inspected, 
six days factory timed and 
tested. He works only for 
jewelers and then only for 
certain jew elers — those that 
agree to sell him for not less 
than $2.50. 

We pay his railroad fare on 
all orders for a dozen or more, 
we brand him with your name 
in lots of 24. 



Height 7 inches. Dial 4/4 inches. Intermittent or Long: Alarm. 
Dealers' names printed free on dials in lots of 24. 
Freight allowed on orders for one dozen or more. - 



Western Clock Mfg. Co< 



New York 



La Salle, Illinois 



Chicago 



503 







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504 



SELF WINDING CLOCK CO 

NEW YORK 



Self Winding Synchronized Clocks, 
Primary and Secondary Clock Systems, 

for 
Railroads, Public and Office Buildings, 
Hotels, Universities, Colleges, 
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Self Winding Program Instruments, 
Jewelers' Regulators, 
Bank Clocks, 

Tower, Post and Bracket Clocks. 
Making Clocks to Architects' designs 
a specialty. 



Hourly signals of correction from the U. S. 
Observatory at Washington, D. C. over the 
lines of the Western Union Telegraph Co. 



505 




Tools, Materials 
and optical Goods 



506 




In 1854 



Waltham Watches 



awakened Europe to the fact that 
the American method of manufac- 
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Since that time the burden of proof 
has been successfully carried by 
17,000,000 WALTHAM WATCHES 
all representing the highest stage of 
the watchmakers' art. 



507 



Howard Clocks 



Are modern in •the sense 
that they are the best 
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although we have been 
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when our business was 
established by Edward 
Howard. W^e guarantee 
satisfaction and respect- 
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I!i£ £• Howard Clock Co. 

BOSTON, NEW YORK AND CHICAGO 

Makers of Clocks but only of the highest grade in their 
respective lines 



Jewelers' regulators, electric 
clocks, house and office clocks, 
locomotive and engine room 
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508 



IqgerscMTenton 

The Best Seven Jewel Watch 

GUARANTEED 



r*5 



to 



[»15 




The first watch guarantee 
ever issued was that placed on 
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For those nineteen years 
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guaranteed?" 



The Ingersoll-Trenton is the first and only 
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The "I-T" has all features of the most re- 
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For seventeen years there has been but one standard in everj^day watches; "Ingersolls" 
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"Junior" at S2.00; and the "Midget" ladies' size at S2.00. Sold by 60,000 dealers orpost- 
paid by us. 

ROBERT H. INGERSOLL & BRO. 

New York Chicago London San Francisco 




509 



THE GREAT 
AMERICAN 
CATALOGUE 



Have you added this Salesman to 
your selling force ? 

Purchasing Goods from the Great 
American Catalogue insures prestige 
and the confidence your customers 
will bestow upon you will be apparent 
in increased patronage. 

Our Catalogue meets with cordial 
approbation of old stand-by customers 
who are in a position to judge of the 
meritorious results obtained through 
constant use, as the best purchasing 
medium. 

Please permit us to send you a copy. 



The Oskamp-Nolting Co. 

No. 411-413-415-417 ELM ST, 
Cincinnati :: :: :: Ohio. 



510 



MOSELEY 




Made Continuously 
for over 30 years 



Imitated — but 
NEVER EQUALED 



The Standard of Excellence 

Nothing is overlooked in their manufacture and no 
expense is spared to make them RIGHT. The Genuine 
Moseley Lathe of to-day is the result of years of painstak- 
ing, systematic and skilled endeavor to satisfy the exact- 
ing requirements of the most critical and experienced 
workmen. 

Moseley Chucks are of the best quality, and are made 
in all sizes; covering every need of the Watchmaker and 
Repairer. These Chucks and Lathes were manufactured 
by us for years under the direct supervision of CHAS. S. 
MOSELEY, the inventor of the "Split Chuck" and" Draw- 
n-Spindle." 

Moseley Lathes and Attachments, with plenty of Mose- 
ley Chucks are the secret of rapid and accurate work. 
They increase your earning power by enabling you to do 
more work in a day. As an investment they pay big 
dividends. 

Write your JOBBER for the NEW MOSLEY 

CATALOG--INSTRUCTION.-REFERENCE BOOK No. 11 

"YOU NEED IT EVERY DAY." 



THERE'S NO LATHE LIKE THE MOSELEY'^ 



511 



Clock Tools and Clock Materials 
form an important and extensive 
item of stock in our Tool and 
Material Department, at 

PRICES THAT DEFY COMPETITION 




No. 2979. Clock Main Spring Winder. 
Nickel plated, $0.50 

In Clock Springs, we keep the best polished only; 
our stock consisting of all die most desirable widths 
on the market. 

If you do not possess our large Tool and Material 
Catalogue, kindly send us your business card and 
procure one. 

We can save you time, money and annoyance; we 
are anxious to make your acquaintance, as we treat 
our customers with the utmost courtesy and attention. 

A trial order solicited. 



Otto Young & Co. 

Wholesale Jewelers and Importers and Jobbers 

Diamonds, Watches, Clocks, Jewelry, Tools, 

Materials and Optical Goods. 

Hesrw^orth Building, Chicago 



512 



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BOSTON COLLEGE LIBRARY 

UNIVERSITY HEIGHTS 
CHESTNUT HILL. MASS. 

BcK>ks may be kept for two weeks and may 
be renewed for the same period, unless re- 
served. 

Two cents a day is charged for each book 
kept overtime. 

If you cannot find what you want, ask the 
Librarian who will be glad to help you. 

The borrower is responsible for books drawn 
on his card and for all fines accruing on the 
same. 




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