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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

f 1 .

/' N

s-^ ^A

1 i
1 1

I 1

\ 1

\ ,

\ !

\ 1

N I
\ 1

•

% '

s 1

•

««. / ^

^ ^

>* . II

- --^..<1-

^-^

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

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

THE MODERN CLOCK.

f-A-

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

y ^
• y

y y

Fig. 3.

THE MODERN CLOCK.

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.

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.

of
rHolir.

0 -■

^ s

0 u

„•

Length
te in 24
meters.

1^1

B 0

;5s

H 0

l.sl

0. -^

-:M

0 '^

♦-1 r::

2 « S

3 -s

y^ .-3

.2 «-

3 Z!

A .t:

2«.S

% J

|oi

y-< 3.

|o|

cS u 0

^ Ki 0

>.°s ■

>^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.)

■J

To Produce in
24 Hours

To Produce

in 24 Hours

1 Minute.

1 M

nute.

1 3

Length
in

2«

t^t

<= i

^%%

'° 'z

Meters.

Loss,

Gain,

^ "

o| S

%r^

1 "-

Lengthen by

Shorten by

Meters.

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

0 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

0 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

0 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

0 0280

0.0268

3,U00

1.4312

1.99

190

700

26.287

0 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

3,577.871

4 9732

4.7586

2,200

2 6612

3.70

8.54

5,152.135

7.1613

6.8521

2,100

2.9207

4.06

3 88

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.

Millimeters.

Equal to

Millimeters

French
Lines.

Inches.

French
Lines.

Inches.

Millimeters

25 39954

11.25951

0.0393708

0.44329

0.088414

2.25583

50.79908

22.51903

0.0787416

0.88659

2
8

0.177628
0266441

4.51166
6.76749

76.19862

33.77854

0.1181124

1.32989

0.355255

9.02332

101.59816

45.03806

0.1574832

1.77318

0.444069

11.27915

126.99771

56.29757

0.1968539

2.21648

0.532883

13.53497

162.39725

67.55709

0.2362247

2.65978

0.621697

15.79080

177.79679

78 81660

0.2755955

3.10307

8
9

0.710510
0.799324

18.04663
20.30246

203 19633

90.07612

0.3149664

3.54637

0.888138

22.55829

22859587

10133563

0.3543371

3 98966

0.976952

2481412

253.99541

112.59515

0.3937079

4.43296

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.

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

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.

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.

o , o

Tor

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

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

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.

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.

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

3 25

3 400

2.098

2.156

.080

.049

.050

3 5

3.944

2.434

2.491

.75

.180

.111

.114

3 75

4 51

2.783

2 865

.321

.198

.204

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

1.287

.794

.816

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

2.897

1788

1837

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.

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

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.

0 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,

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.

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.

■±;

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.

l.lVtfMut 3

s 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

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.

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.

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

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

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

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

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

!=ii;iuMfj%Miii,m ^: — iMnmfipi,i,mii=>

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,

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

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,

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.

THE MODERN CLOCK.

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.

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

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.

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

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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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.

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

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

THE MODERN CLOCKo

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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

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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

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.

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

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.

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.

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

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

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.

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.

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 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

no:

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.

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,

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

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

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^. ""

ttiJIi-

i^fed

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mt H"

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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.

First collet driven.

Second collet driven.

Third collet driven.

Shoulder turned.

First sides faced.

Second sides faced.

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

to , r!

5?'2 c

c4 <1>

III

120 90 75

10 10 9

Double

*30

156.56

96 76

114

10.82

31eg-

115 100

115

10-65

ffo'

84 78

115.9

10.49

120 90 90

10 9 9

*40

88.07

96 80

120

9.78

128 120

39.14

84 70

120

9.78

112 105

39.14

84 78

120.3

9.73

96 90

39.14

90 84

122

9.46

80 75

39.14

84 78

124.8

9.02

64 60

39.14

100 80

125

9.01

68 64

30.49

90 84

126

8.87

70 64

28.75

100 96

128

8.59

72 64

27.17

84 78

129.3

8.42

75 60

25.05

100 78

130

8.34

72 65

23.15

84 77

132

8.08

75 64

22.01

84 78

133.7

7.9

84 64

19.97

90 90

135

7.73

86 64

19.06

84 78

138.2

7.38

88 64

18.19

84 80

140

7.18

84 78

89.1

17.72

120 71

142

6.99

80 72

17.39

84 78

142.6

6.93

84 78

93.6

16.08

100 87

145

6.69

94 64

15.94

84 78

147.1

6.5

84 78

■ 28

95.5

15.45

100 96

150

6.26

108 100

12&10

15.28

84 78

151.6

6.1

84 84

9& 8

14.66

96 95

152

6.09

84 78

14.66

84 77

154

5.94

84 78

98.9

14.41

104 96

156

5.78

80 80

100

14.09

84 78

156

5.78

85 72

102

13.54

120 96

9&8

160

5.5

84 78

102.4

13.44

84 78

160.5

5.47

84 78

102.5

13.4

84 78

164.9

5.15

105 100

105

12.78

132 100

9&8

165

5.17

84 78

105.8

12.59

84 78

169.4

4.88

84 78

107

12.3

128 102

170

4.87

96 72

108

12.08

84 78

173.8

4.65

84 78

109.2

11.82

36 36 35

175

4.6

88 80

110

11.64

84 77

176

4.55

84 77

110

11.64

84 78

178.3

4.43

84 78

111.4

11.35

45 36 36

180

4.35

84 80

112

11.22

47 36 36

188

3.99

84 78

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.

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

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.

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^-

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

0 0

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.

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 ■

-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=iE

■rJ

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.

3te

22:

■f^^^M^gJfFF?^!

Hour.

m^-

i3t

^^^

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,

RbO

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

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

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 ^rMggwriHi'^

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

rr"--"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,

1
I

I I I I

® ® (9) ^

■//7<su/ofed

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

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

Dedendum 202

Dial Work 295

Diameters of Wheels, Getting 196

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

Friction Springs 294

Grandfather clocks S52

Hypocycloid 206

Keyhole Plates 289

Lever Escapement for Clocks 193
Levers, the Elements of 99, 100, 101

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

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

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

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

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

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

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

Gathering Pallet 338,344

Gilding 459

Gong Wires 369

Graham Escapement 109,467

Gravity, Center of 18

" Escapement 150

Gregorian Calendar 349

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

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

Need for Information 3

Numbers, Conversion of 201

Nut, Rating 42,50,66

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

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

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

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

Varnish for Dials 438

•* Remover .456

Vibrations of Balance 180

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

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
model alarm clock standing 7
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
across the largest room.

Big Ben rings just when you

want and either way you want,
intermittently for fifteen min-
utes, continuously for ten,
and he rings with a jolly full-
tone ring that will arouse the
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,
Schools and Private Residences.

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-
turing produces the best watches.
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
timekeepers in the world
although we have been
making them since 1842,
when our business was
established by Edward
Howard. W^e guarantee
satisfaction and respect-
fully solicit your business.

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
clocks, marine clocks, pro-
gramime clocks, post or side
walk clocks, tower clocks,
watchman clocks, employes'
time recorders.

508

IqgerscMTenton

The Best Seven Jewel Watch

GUARANTEED

r*5

[»15

The first watch guarantee
ever issued was that placed on
the cheapest watch ever made
— the Dollar Watch — nine-
teen years ago.

For those nineteen years
while selling nearly nineteen
million Ingersoll watches, we
have been asking: "Why are
expenslue^je^weled watches not
guaranteed?"

The Ingersoll-Trenton is the first and only
high grade 7-iewel watch made complete and
cased in one factory ; and therefore, the only
one that can be guaranteed by its makers;
others are assembled from movements made in
one factory and cases from another, by the
dealer, often a competent jeweler, but often,
too, without facilities such as the adjusting- and
timing synems existing in our complete -watch
factory.

The "I-T" has all features of the most re-
cent, costly watches, which secure accuracy.
"l-T" gold-filled cases contain gold enough to
outlive their guarantees. Sold only through
responsible jewelers, who buy direct. If not on
sale in your town we will send, prepaid ex-
press, on receipt of price.

INGERSOLL WATCHES

For seventeen years there has been but one standard in everj^day watches; "Ingersolls"
have popularized the very use of watches. One friend says, "They have made the dollar
famous." They have never been so worthy of their great reputation as today. Fully guaran-
teed. They include; The Dollar Watch; the "Eclipse" at S1.50; the new thin model
"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

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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.

,4'

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