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Full text of "Cold-heading"

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COLD-HEADING 

MACHINES, METHODS AND TOOLS USED FOR 

THE COLD-HEADING OF SCREWS, RIVETS 

AND SIMILAR MACHINE PARTS 

BY CHESTER L. LUCAS 




MACHINERY'S REFERENCE BOOK NO. 119 
PUBLISHED BY MACHINERY, NEW YORK 






MACHINERY'S REFERENCE SERIES 

EACH NUMBER IS ONE UNIT IN A COMPLETE LIBRARY OF 

MACHINE DESIGN AND SHOP PRACTICE REVISED AND 

REPUBLISHED FROM MACHINERY 



NUMBER 119 

COLD-HEADING 

By CHESTER L. LUCAS 



CONTENTS 

Principles of Cold-heading - - - - - - - 3 

Cold-heading Machines and Operations - - - - 16 

Cold-heading Dies and Tools - ,-' - > - - - 32 



Copyright, 1914, The Industrial Press, Publishers of MACHINBKT, 
140-148 Lafayette Street. New York City 



CHAPTER I 



PRINCIPLES OP COLD-HEADING 

The operation of forming the heads of rivets, wood screw blanks, 
machine screw blanks, and similar products, by upsetting the ends of 
the wire lengths while cold, is known as cold-heading. The machines 
to which the wire is fed from a coil, and in which it is cut off and 
headed, are known as cold-headers. It is the purpose of th'is treatise to 
describe briefly the operation of various types of heading machines, to 
enumerate some of the limitations and possibilities of the different 
cold-heading machines and to give a general idea of the way in which 
the tools are planned and made for this class of machinery. No at- 
tempt will be made to cover the heading of hot stock such as is fol- 
lowed in making hot-formed bolts, as this type of machinery comes 
under the head of forging machinery, and is separately described in 
MACHINERY'S Reference Books No. 113, "Bolt, Nut and Rivet Forging," 
and No. 114, "Machine Forging." 

Principles of Cold-heading- 

If we should cut off a piece of %-inch diameter copper wire about 1 
inch long, stand it on end on a hardened steel block, as shown at A, 
in Fig. 2, and strike it squarely on top with a heavy hammer, we 
would upset the piece as a result of the blow, causing it to bulge con- 
siderably at the center, the amount depending upon the force of the 
blow, leaving it with an appearance as indicated at B, Fig. 2. Con- 
tinuing our experiments, if we take another %-inch piece of copper 
wire, 1 inch long, as before, and drop it into a %-inch hole in a hard- 
ened steel block, allowing a section y 2 inch long to extend above the 
surface of the block, as at (7, Fig. 3, and strike the ^nd of this piece 
a square blow with the same hammer, the piece will assume about the 
appearance indicated at D, in Fig. 3. The projecting section will be 
bulged as before, but the part of the blank remaining within the block 
must necessarily retain its original shape, as it is confined in all di- 
rections. Continuing our experiments still further, if we take a new 
blank of the same dimensions and insert it in the same block as be- 
fore, but in place of the flat ended hammer we use one with a cup- 
shaped depression turned in its face, as shown at E, Fig. 4, and strike 
the blank a hard blow squarely upon the projecting end, the end of the 
wire will necessarily take on the appearance indicated at F, Fig. 4. 
The blank must assume this shape because the part under the head is 
confined within the lower block and the head section is guided in its 
bulging by the cup-shaped depression in the hammer with which the 
blow is struck. 

These three simple experiments outline the principles involved in 
cold-heading. In all cold-heading operations the blank is confined at 



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4 No. 119 COLD-HEADING 




GENERAL PRINCIPLES 




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6 No. 119 COLD-HEADING 

he moved to Ramapo, N. Y. His heading machine was a massive af- 
fair, with a heavy framework anchored to the floor. A large fly- 
wheel was provided, and the machine was operated on the now 
familiar toggle principle. In 1838, the Eagle Screw Co., of Provi- 
dence, R. I., was started by William G. Angell, and its earliest ma- 
chine was what is known today as the old Eagle header. At the 
factory of the American Screw Co., Providence, R. I., this type 
of machine is used today on certain classes of work. Mr. Benjamin 
Thurston, superintendent of the American Screw Co., states that in the 
early days of cold-heading each machine was mounted upon the ends 
of long posts which ran through the floor down to a solid ground 
foundation. 

An Old Type of Header 

In Fig. 5 is shown one of the earliest cold-heading machines now in 
existence, and while it has long ago out-lived its usefulness, it is inter- 




Fig. 5. An Old Type of Header 

esting to compare it with modern heading machines. This machine 
was designed by W. E. Ward and built by Russell, Burdsall & Ward, 
of Port Chester, N. Y., at some time prior to 1856. The line engraving 
Fig. 6 gives an idea of the general principles upon which this machine 
operated, from which it will be seen that the operation of the punch 
was effected by means of toggle mechanism actuated by a cam on the 
lower shaft of the machine. The vertical cross-section through the 
dies is indicated at the left. As the machine was of the open-die type, 
the lower die was actuated by another cam. Two extremely heavy 
rods extended the length of the sides, as shown in the engraving, Fig. 
5, and in section in the illustration, Fig. 6. These served to tie the 
machine together, enabling it to better withstand the heading opera- 
tion. The output of this machine, which was used for making stove 
bolts % to % inch in size, was about 30,000 headed pieces per day of 
eleven hours. 

Operating- Principle of Modern Heading- Machines 

Practically all modern heading machines operate upon the same gen- 
eral principle, although there are many modifications and features 



GENERAL PRINCIPLES 



which each maker considers best. By referring to Fig. 7, which shows 
the plan view of a modern single-blow solid-die heading machine, it 
will be seen that there is a heavy framework A, at one end of which 
is located the driving shaft B, rotated by a driving wheel at the right- 
hand side; at the other end is located the die-block C. Between the 
sides of the heavy framework is a movable ram D which serves to 
actuate the heading punch E. The wire, which is indicated at F, 
enters the machine through feed rolls G and thence through the frame- 
work of the machine, passing through the cut-off quill H. At the left- 
hand side of the machine is supported the bracket 7, in which slide J 
may be reciprocated by means of a crank motion from the main driv- 
ing shaft. Slide J contains a cam groove in which roll K is fitted, and 
as roll K is mounted upon the cross-slide L, it will be seen that a 
lateral motion is thus imparted to the cut-off knife M, located on the 





LONGITUDINAL SECTION 

TO SHOW 
TOGGLE ACTION 

TOGGLE OPERATING 
CAM 
Machinery 



Fig. 6. Diagram illustrating Operation of Header shown in Fig. 5 

end of cutter bar. The ratchet feed advances the wire through the 
cut-off quill to the feed stop, not shown, after which cut-off knife M 
is advanced in the manner just described, severing the wire, but retain- 
ing it on the cut-off blade by means of a spring finger. The advance 
of the cut-off knife and wire is continued until it reaches a position 
directly in front of the opening in die N. At this position it is held 
stationary long enough for punch E to begin to push it into the die, at 
which time the cut-off knife retreats and allows the punch E to con- 
tinue its work by pushing the blank to the bottom, of the die cavity, 
afterward upsetting the projecting part of the wire to form the head. 
The wire blank F, when pushed into the die, is prevented from passing 
too far by a backing pin 0. After the piece has been headed, the 
backing pin is advanced by ejecting mechanism operated by lever P, 
which receives its motion from a crank on the right side of the ma- 
chine connected to the main driving shaft. This, briefly stated, is the 
general principle upon which all modern heading machines of the 
single-blow solid-die type operate. 

There are two distinct principles employed for reciprocating the 
movable ram of a cold-header. These are the crank principle and the 



8 



No. 119 COLD-HEADING 



toggle principle. In the machine just described and illustrated in Fig. 
7, motion is transmitted to the ram by means of an eccentric upon the 




Machinery 



Tig. 7. Plan View of a Modern Cold-header 

driving shaft, the eccentric, of course, being a modification of the 
crank principle. By referring to the diagram Fig. 8, it will be seen 
that in the crank-operated header the length of the stroke is equal 
to the diameter of the crankpin circle, and that one stroke is accom- 



GENERAL PRINCIPLES 



plished in each, revolution of the driving shaft from which the crank 
is operated. 

The crank principle is employed on most single-stroke machines and 
by one manufacturer for double-stroke machines as well. On double- 
stroke cold-headers of the crank-operated type, it will be seen that the 
crankshaft must make two revolutions to secure the two strokes, and 




Machinery 



Fig. 8. Diagram to illustrate Operation of Crank Headers 

these two strokes will be of equal length. The blow secured by the 
crank-operated header is of a quick punching character rather than 
a gradual squeezing operation, and exponents of crank-operated headers 
consider this feature to be of great importance. 

Tog-g-le-operated Headers 

The other principle upon which cold-headers operate is the toggle 
principle, of which there are several variations. The common type of 




Fig. 9. 



Diagram to illustrate Operation of Toggle Headers of 
Two-cycle Type 



toggle action is that shown in Pig. 9, in which the toggle is straightened 
by a crank-actuated link, which brings the arms of the toggle to a 
straight line once during each revolution of the crankshaft. This, of 
course, gives one stroke of the ram to each revolution of the crank- 
shaft, but the blow obtained is of a gradual squeezing character, especi- 
ally at the ends of the stroke where the greatest amount of work 



10 



No. 119 COLD-HEADING 



is being done. This type of toggle mechanism is known as the two- 
cycle type, two revolutions of the crankshaft being necessary to com- 
plete a "two-blow" rivet. Another type of toggle operating mechanism 
which is extensively used on the double-stroke machines is illustrated 
in Fig. 10, from which it will be seen that two blows are struck at 
each revolution of the crankshaft which operates the arms of the 
toggle. As this type of machine makes a two-blow rivet in one revolu- 
tion, it is termed a "one-cycle" machine. The chief difference between 
the two-cycle type of toggle action and the one-cycle type lies in the 
fact that in the two-cycle mechanism the toggle is straightened when 




Machinery 



Fig. 10. Diagram to illustrate Operation of Toggle Headers of 
One-cycle Type 

the extreme of the crank motion is reached, but in the one-cycle 
mechanism it is straightened midway of the extreme distance of the 
crank, so that in the latter machine two blows are secured during one 
revolution of the crankshaft. The two strokes may be of equal length; 
the first stroke may be the longer, or vice versa, by varying the dis- 
tance between the crankshaft and the line of the straightened toggle. 
In Fig. 10, the first blow is the long blow as the toggle is pushed down 
to the straightening point. As the toggle is drawn further above the 
straightening line than it was below, the second blow will be the short 
one, as indicated. 

Double^stroke Cold-headers 

In describing the header illustrated in Fig. 7, it was stated that this 
was a single-stroke machine as contrasted with- a machine for striking 



GENERAL PRINCIPLES 



11 



two blows on each piece. A great many jobs of heading, however, 
cannot be adequately handled on a single-stroke machine, as there is 
too much metal to be upset in the head. When the amount of metal 
to be put into the head exceeds two and one half diameters of the wire 
in length, it is necessary to employ a double-stroke machine. The 
double-stroke machine operates in practically the same way as that 
shown in Pig. 7, except that it strikes two blows in rapid succession 
upon the wire blank before it is ejected. The preliminary blow is 
known as the coning blow; in this the wire is partly upset and pre- 
pared for the second, blow which finishes the head. The two punches 
are "slidably" held on the ram, and the mechanism for changing the 
positions of the dies for the two blows is called the rise-and-fall mo- 
tion. While there are several different means of securing this motion, 



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Machinery 



Fig. 11. Mechanism for operating- Ingraham Rise-and-fall Motion 

the Ingraham rise-and-fall motion used on Blake & Johnson cold- 
headers is typical. By referring to the line illustration Fig. 11, which 
shows a side elevation of the principal parts, in connection with the 
halftone illustrations Figs. 12 and 13, the operation of this device can 
be readily followed. Upon the end of ram A, the die-holding slide B 
is secured. This slide is free to move vertically so that upper punch 
G or lower punch D may be operated in alignment with the stationary 
die. In Figs. 12 and 13, these dies are not shown. Pivoted upon 
bracket E, which is bolted to the left side of the frame, as shown in 
Figs. 12 and 13, is the lever F which controls the rise-and-fall movement 
of the punch slide. This lever is actuated by a cam upon the driving 
shaft of the machine, as indicated at G, Figs. 12 and 13. At the op- 
posite end of lever F, a bearing pin H is adjustably mounted, being 
free to slide in the ways provided in section I of the punch-holding 
slide. Thus by having cam G of the proper shape, the rise and fall 
of punch-holding slide B may be so timed that at the time of the po- 
sition of the first blow, punch C will be in line with the die, and at the 
time of the position of the second blow, punch D will be in line with the 



12 No. 119 COLD-HEADING 

die. It is obvious that on double-stroke machines, the wire feeding, 
cut-off and ejecting mechanism must be geared to agree with every 
second stroke of the ram. 

Triple-stroke Headers and Reheaders 

In addition to single- and double-stroke machines, triple-stroke 
headers are sometimes used where the amount of metal to be dis- 




Fig. 12. Plan View of Blake & Johnson Double-stroke Solid-die Header 

placed is more than can be effected with two blows. Triple-stroke 
headers are similar in action to other headers, except that three 
blows are struck. Two blows, however, will usually upset the metal 
of most heads to a point of crystallization so that except in special 
instances the use of a third blow would be of no advantage, because 
the blanks would require annealing before a third blow could be 
struck. Many heading jobs require two distinct operations to per- 
form the work, usually on account of the shape of the pieces. For this 



GENERAL PRINCIPLES 



purpose the work is carried as far as possible with an ordinary single- 
or double-stroke header, after which the pieces are annealed and com- 
pleted in a reheader. By means of an automatic hopper feed, the 
partly formed pieces are placed in the heading dies and the subse- 
quent operations performed. Reheaders are made with strike one, 
two or three blows. 

Open-die Machines 

Thus far we have only described single- and double-stroke machines 
of the solid-die type, but for handling work in which the length of 




Fig. 13. Phantom View to illustrate Operation of Ingraham Rise-and-fall Motion 

the pieces under the head exceeds nine or ten diameters of the wire, 
it is necessary to employ dies which open longitudinally to make 
ejection of the work possible. The heading operation upsets the 
metal of the blank for its entire length in addition to the upsetting 
of the head, so that the metal of the shank is squeezed out against 
the sides of the die. In the case of a solid die this upsetting of the 
metal in the shank makes the resistance to ejection too great, especially 
when the work has a very long shank. 

Cold-headers employing open dies require die-operating mechanisms 
of an entirely different character from that which is used in solid- 



14 



No. 119 COLD-HEADING 



die machines. By referring to Pigs. 14 and 15, the operation of the 
dies of a machine of this type may be followed. Referring to Fig. 14, 
the framework of the header is shown at A, the ram at B, and the 




Figr. 14. Construction of Die-operating Mechanism for Open-die Headers. 
Fig. 15. Side Elevation of Dies and Spring Pin 

punch at C. The two halves which constitute the dies are shown at 
D and E. The wire, which is indicated at F, runs through straighten- 
ing rolls of the usual type through the framework of the machine as 
well as the die-holding block, and thence through the dies them- 



GENERAL PRINCIPLES 15 

selves. In feeding, the wire is run out against a stop, not shown, 
and is cut off by the movement of the two halves of the die in unison 
toward the right, which also brings the wire blank over into line 
with the heading punch C. Different makers of cold-headers use 
different methods for moving the die-blocks, and one of these con- 
structions is here illustrated. The action of this mechanism is best 
shown by the sectional view in Pig. 14. A flat cam G is reciprocated 
by a crank connection to the driving shaft of the machine. When this 
flat cam is pushed in, it raises the toggle of which arms H and / are 
members. This action tends to straighten another toggle composed 
of arms / and K, and in straightening the latter toggle, slide L is 
made to push die-halves D and E laterally, thus severing the wire and 
moving it into the heading position. A spring pin M assists in return- 
ing the toggle mechanism for another operation. By referring to the 
sectional illustration, it will be seen that the corners of the two halves 
of the die are chamfered. A wedge pin N, more clearly shown in the 
smaller illustration, Fig. 15, fits into this chamfered opening at the 
parting line, and by means of a flat spring which presses downward 
upon the wedge pin, it tends to force the dies apart whenever lateral 
pressure is removed. This, of course, facilitates the ejection of the 
headed piece, which takes place when the new length of wire comes 
forward. Similarly, two spring pins are provided which press 
against a filler block P on the opposite side from the die-operating 
plunger L. These serve to return the dies to the cut-off position after 
the piece has been headed. 

In the heading position the rear end of the wire blank is backed 
up by backing plate Q, which is of hardened steel, so that the rivet 
or screw blank is effectively contained while being headed. From 
this construction it will be seen that the length of the dies must be 
the exact length of a headed rivet or screw blank measured under 
the head. 



CHAPTER II 

COLD-HEADING MACHINES AND OPERATIONS 

In the preceding chapter the principles of cold-heading, together 
with its early history and a general outline of the machines employed, 
were given. In this chapter a brief description of representative 
machines of each of the principal types of cold-headers will be given, 
with statements of the possibilities and limitations of the work which 
may be done on each of these classes of machines. From the preced- 
ing pages it will, be gathered that all cold-headers, whether of the 
crank- or toggle-operated types may be divided into single- and double- 
stroke machines on the one hand, and into solid- and open-die machines 
on the other hand. When we consider that single-stroke machines 
may be of solid- or open-die types, and double-stroke machines of 
solid- or open-die types either crank- or toggle-operated, and that the 
toggle-operated machines may be either one- or two-cycle type, it will 
be seen that to describe each of the combinations that are found in 
cold-heading machinery would be an endless task. In addition to the 
above-mentioned class of heading machinery, there are reheaders of 
single-, double- and triple-strokes; and in the special industries like 
that of tack- and nail-making the machines are still more special, but 
by describing the most common of the machines in general use an 
adequate idea of cold-heading machinery will be given, as the general 
operating principles are similar. 

E. J. Manville Single-stroke Solid-die Cold-header 

The single-stroke solid-die header is undoubtedly the simplest of 
all, and for that reason has been selected for the initial description. 
This machine is built in six sizes; the smallest size handles wire up 
to % inch diameter and the largest, which is the machine illustrated 
in Fig. 16, handles wire up to % inch diameter. The frame is of very 
heavy section and the crankshaft, which is of large diameter, is made 
of forged nickel steel. The bushings which support this crankshaft 
have their bearings close to e&ch side of the crankpin so that there is 
little danger of bending the crankshaft by the heavy work required in 
cold-heading. The wire is fed in from the front of the machine through 
the usual type of grooved roll and is lubricated by a reservoir below 
the lower feed-roll. The cut-off is operated from the side in the manner 
described in the previous chapter, and on this machine a safety con- 
nection is provided between the crank and cut-off cam slide. This is in 
the form of a shear pin so that if excessive load is placed upon the cut- 
off knife the machine will stop without doing damage other than shear- 
ing the safety pin. A patented form of cut-off knife is employed so 
that the blank will be held rigidly while being sheared and thus cut 
squarely. This is an essential feature on single-stroke machines, for 
as there is no preliminary or coning blow to centralize the stock, it 



MACHINES AND OPERATIONS 



17 




Fig. 16. Single-stroke Solid-die Cold-header E. J. Manville Make 




Fig. 17. Double-stroke Solid-die Cold-headerBlake & Johnson Make 



18 No. 119 COLD-HEADING 

must go to the dies in good condition after being cut off. The bal- 
ance wheel is very heavy in design, and as it is essential that a 
heading machine be stopped at some point other than the center, a 
foot brake, shown in Fig. 16, is provided, so that the wheel may be 
stopped at any desired point in its revolution. 

Single-stroke headers of the open-die type are not very largely 
used except in the wood-screw industry. The main point of difference 
between this type of machine and the one previously described is the 
die-operating mechanism, and this mechanism was described in gen- 
eral in the preceding chapter. 

Blake & Johnson Double-stroke Solid-die Cold-header 

Fig. 17 illustrates a double-stroke solid-die header made by the 
Blake & Johnson Co. of Waterbury, Conn. This machine is one of the 
latest of its class and has some radical differences which are worthy 
of description. This is the first header to be made with a pan or tray 
between the frame and legs. In addition to catching dripping oil and 
odd ends of wire it furnishes a shelf for catching the finished work. 
This form of construction results in a more rigid machine than any 
of those types where long slender legs are employed. By observing 
the cut-off cam-slide mechanism at the center of Fig. 17, it will be 
seen that the cam groove is cut in the face of a segment rather than 
in a slide. This segment is pivoted on a stud as shown, and it is 
claimed that less power is required for its operation; in addition it 
makes a more compact arrangement. The connecting-rod which 
operates the cut-off cam is held by clamping at its operating end and 
when this clamp is set to the proper tension to do the work it acts as a 
safety device, allowing the connecting-rod to slip if excessive strain is 
placed upon it. The distinguishing feature between single- and double- 
stroke machines is the rise-and-fall motion which must be used for 
raising and lowering the punch-block so that the two punches strike 
alternately on the head of the wire blank. The mechanism that pro- 
vides for this is the Ingraham rise-and-fall motion which was fully de- 
scribed in the previous chapter. This type of mechanism has the ad- 
vantage of being located at the top of the machine where it is most 
accessible and convenient to adjust. 

On this machine lubrication is provided for by dripping oil from a 
cast-iron pot that is mounted on a stud at the head of the machine. 
From this pot the oil drips to a hole in the bed over the wire line from 
which it drops on the wire just before the latter enters the dies. Lubri- 
cation is an important feature on cold-headers especially w r hen annealed 
steel or iron wire is being worked, because the lime film which remains 
from the annealing operation renders the wire hard to eject unless lub- 
ricated. The feed is operated by the three-pawl system so that the fin- 
est adjustments of feeding lengths may be obtained. The crankshaft 
bearings are cored out and provided with chain oilers, which are a new 
feature on cold-headers. The capacity of this machine is the heading of 
blanks 3/16 inch diameter up to l 1 ^ inch length under the head. 



MACHINES AND OPERATIONS 19 

Waterbury-Farrel Double-stroke Solid-die Header 

One of the most popular of the double-stroke solid-die headers is that 
made by the Waterbury Parrel Foundry & Machine Co., Waterbury, 
Conn. The machine is made in one- and two-cycle types, shown in Pigs. 
18 and 21, respectively. Both of these machines are of the toggle-oper- 
ated type; the operating principles of one- and two-cycle headers were 
explained in Chapter I, "Principles of Cold-heading." The machine 
illustrated in Fig. 18 is the No. size and has a capacity for heading 




Fig-. 18. Double-stroke Solid-die Cold-header, One-cycle Type Waterfoury 
Farrel Foundry Make 

wire up to and including one-eighth inch in diameter. It is designed to 
handle wire rivets or blanks up to one inch in length, under the head, 
this being the largest amount of one-eighth inch wire that can be easily 
ejected from a solid die. This machine has been highly developed and 
embodies all the latest improvements in heading machinery. On ac- 
count of its being of the one-cycle type, striking two blows to each revo- 
lution of the flywheel, the machine can be run at a comparatively slow 
speed and still obtain a large production. As is usual in solid-die ma- 
chines, the wire is fed through feed rolls and a cut-off quill, and brings 
up against a rigid feed-stop so that the length of the feed is arbitrarily 



20 



No. 119 COLD-HEADING 



determined. The cut-off bar is of the usual type carrying a cut-off blade 
at its end and in most instances the cutting off and carrying is done 
with the aid of a ''fiddle-bow" carrier. 

This fiddle-bow carrier, perhaps, needs a word of explanation, and for 
that reason is shown in detail in Fig. 19. The purpose of this type of 
carrier is to back up the cut-off blade when severing the wire and assist 
in transporting the blank to the heading die. In Fig. 18 a view of the 
fiddle-bow carrier may be seen. From this, in connection with Fig. 19, 
which is a view of the die end of the machine from the inside, it will be 
seen that the mechanism consists of a carrier A, supported in a bracket 
B at one end, pivoted and actuated by end bracket C which is bolted to 
the end of the cut-off slide. At the operating end of carrier A, an arm 
D is pivoted, being normally kept in its uppermost position through a 




Machinery 



Fig. 19. Construction of the "Fiddle-Bow" Carrier 

spring-encircling rod E. This rod is slotted at the upper section so that 
the arm D is free to move up or down. Finger F is the active part of 
this carrier, and when the wire emerges from the cut-off quill G, this 
finger is on the opposite side from the cut-off blade, being held there by 
pressure of the spring located on rod E. When the cut-off blade advan- 
ces, the wire is prevented from being deflected at its outer end under the 
cutting pressure and is held perfectly square while the cut is being 
made. Now when the cut-off blade advances with the blank toward the 
heading die H, the fiddle-bow carrier mechanism also advances through 
contact of bracket C with carrier A which slides through supporting 
bracket B. After it is in the heading position and the blank partly has 
entered into the die, the cut-off slide returns and finger F of the carry- 
ing mechanism snaps back over the wire and brings up against the new 
length of wire which has advanced through the cut-off quill G. The ad- 
vantage in using this type of carrier is that the wire is supported be- 
hind the cutting action and a square end of the blank is the result. This 
is important, for if the cut is not square, the head of the finished pro- 
duct will be "lop-sided." 



MACHINES AND OPERATIONS 



21 



The heading operations are actuated by the well-known powerful 
knuckle-joint mechanism, of which the Waterbury Farrel Foundry Co. 
are exponents, and as was explained in the preceding chapter, the one- 
cycle type is characterized by the striking of one long stroke and one 
short stroke of the heading slide as contrasted with two strokes of even 
length in the two-cycle type. The relative length of the two strokes may 
be governed by the design of the toggle mechanism, and it is customary 
to strike the long blow which does the coning or bulbing first. The 
second blow, which completes the heading, is taken care of by the short 
stroke; the reason for this is that concentrating the same amount of 
power into a short stroke gives a more powerful heading effect just 
what is wanted for the final setting of the wire. On this make of ma- 







Ct 



Machinery 



Fig. 20. Typical Examples of Beheading requiring an Open-die Machine 

chine, the heading slide has ample wearing surfaces and is gibbed for 
taking up wear. 

The toggles, upon which so much depend in this class of machinery, 
are made of a special grade of bronze with adjustable steel side plates 
for taking up wear. The connecting toggle-pin is, of course, of tool 
steel, hardened and ground. One important feature of the toggle con- 
struction is that the machine can easily be brought "off centers" by 
hand, in case it should get stuck while operating upon a damaged blank 
or on account of excessive pressure. This construction also makes the 
setting of the tools easy when operating the machine by hand. The 
feed mechanism is of the usual type with two grooved cast-iron feed- 
rolls through which the wire passes. Cast-iron rolls are used as it has 
been found that the wire slips less than when steel rolls are employed. 
By means of a pawl-arm operated from an eccentric on the crankshaft, 
the length of the feed can easily be adusted even though the machine is 
in motion. The cut-off is operated through a cam slide which may be 
seen at the right of the machine. This cam-slide operates back and 



22 No. 119 COLD-HEADING 

forth through the cut-off bracket, thus actuating the cut-off blade. A 
safety slip device is provided so that if excessive strain is brought 
against the cut-off blade, the blade will not be broken, but will be stop- 
ped in its action by the slipping of the safety mechanism. The punch- 
shifting mechanism is positive, the punch-slide being shifted both in its 
up and down position against stop-screws so that they will surely be in 
line when the respective blows are struck. Adjustment is provided so 
that the punches may be moved sidewise, up or down, or longitudinally. 
The longitudinal adjustment is obtained from a broad wedge in back of 
the toggles at the end of the frame. The knockout is located in the end 
of the bed and ejects the work from the die by means of a lever that 
pivots in the feed-roll bracket, operated from a cam on the crankshaft. 
The entire thrust of the heading blow is taken on a stop-screw which 
backs up the knockout pin and accurately determines the correct 
length of rivet made. 

Double-stroke Solid-die Geared Header Two-cycle Type 

The Waterbury Farrel Foundry Co. also makes a solid-die double- 
stroke header of the two-cycle type, and Fig. 21 shows the No. 3 size of 
this machine. It has a capacity for heading three-eighths inch rivets 
at the rate of fifty-five per minute. This is a geared machine of great 
power, and it requires two revolutions of the crankshaft to produce each 
rivet, in accordance with the two-cycle principle. This means that the 
feeding, cut-off and ejecting mechanism is geared down so that these 
functions operate only once while the heading slide is making two 
strokes. While this machine is more powerful than the one-cycle type, 
it is, of course, slower in its action, and the crankshaft and toggle me- 
chanism must go through twice as many motions to produce a rivet as 
was the case in the one-cycle type. As in the previously described ma- 
chine, the wire passes through the feed-rolls and cut-off quill and brings 
up against the feed-stop. The cut-off blade is actuated in connection 
with the fiddle-bow carrier which holds the blank to the cut-off blade 
and assists in carrying it to the heading position in line with the die. 
The upper heading punch strikes the first blow, forcing the blank into 
the die and centralizing the wire preparatory to the second blow which 
is struck by the lower punch, thus forming the finished head. The 
heading slide then draws back and the punches are shifted down ready 
to operate on the next blank. 

The crankshaft is of large size and runs in bronze lined bearings on 
the larger machines. The flywheels, of which there are two on the 
large size machine, are held to the crankshaft between friction disks 
which slip and prevent damage to the machine should undue strain be 
imposed. The toggles on the machines are made of the best grade of 
cast iron, and provision is made for taking up the wear. The feed and 
cut-off mechanism are the same as in the type of machine previously 
described, and a safety shear pin is provided so that should the head- 
ing die become loose and project out far enough to prevent the cut-off 
knife from passing, or should the cut-off knife be obstructed from any 



MACHINES AND OPERATIONS 



23 




Fig. 21. Double-stroke Solid-die Cold-header, Two-cycle Type 
Waterbury Farrel Foundry Make 




Fig. 22. Double-stroke Open-die Cold-header E. JV Manville Make 



24 No. 119 COLD-HEADING 

other cause, the safety shear pin will be severed, causing no other 
damage to the machine. This shear pin is a plain straight piece so 
that it is a simple matter to insert a new one. 

A relief motion can be furnished for this machine if desired. It con- 
sists of a mechanism that allows the knockout pin, against which the 
blank is forced during the heading operation to draw back after the 
blow is struck. This allows the metal to flow into the dies more freely 
on the second blow, and is especially desirable on such work as requires 
squares or shoulders underneath the head. By a proper knowledge of 
the use of this relief motion, a great many difficult jobs of heading can 
be accomplished with facility. 

E. J. Manville Double-stroke Open-die Cold-header 
Double-stroke cold-headers of the open-die type are the most compli- 
cated ot the ordinary run of heading machines, for in addition to the 
rise-and-fall motion for operating the punch block, provision must be 
made for opening and closing the dies. In Fig. 22 is shown the E. J. 
Manville double-stroke open-die header. This machine is made in four 
sizes; the one illustrated is the No. 4 machine which handles wire up to 
one-half inch diameter. This header is of the crank-operated type, and 
the wire enters through feed-rolls of the usual type and thence to its 
cut-off position between the square dies. The dies are then forced side- 
wise, shearing the wire and carrying the blank over to the heading posi- 
tion. When in line with the backing block, the first or coning punch 
centers and partly heads the wire, leaving it in condition for the second 
punch to finish the work. On this machine the punches are locked auto- 
matically in both up and down positions while the blows are being 
struck. Another distinguishing feature of this machine is that the 
wire feed is operated from the right-hand side of the machine as may 
be seen in Fig. 22. This leaves the front corner of the machine on the 
wheel side free from all mechanism so that the operator can observe 
the working of the tools easily. 

The feed-pawl operates only at every second stroke of the machine, 
for it will be remembered that this is a double-stroke machine. By 
means of a handwheel which may be seen opposite the lower parts of 
the ratchet feed wheel a quick and accurate setting of the pawl may be 
made and it may be regulated while the machine is running. The wire 
feed is easily started or stopped by a hand lever. 

A safety connection is provided between the die-operating cam and 
the crankshaft, in which there is a cast-iron plate. Should any obstruc- 
tion prevent the dies from closing, this cast-iron plate will break and 
drop to the floor, thus instantly disconnecting the crank and cam-slide. 
An automatic throw-off instantly stops the wire from the feed when 
this safety device is brought into play. This machine is also provided 
with a foot brake to assist in stopping the header at the proper point. 

Waterbury-Farrel Double-stroke Solid-die Reheader 
The varieties of reheaders are almost as numerous as all the other 
types of headers combined. The most common types, however, are the 



MACHINES AND OPERATIONS 



25 



single- and double-stroke machines of solid- or open-die types. A repre- 
sentative machine of the double-stroke solid-die type is illustrated in 
Fig. 23 which shows a machine made by the Waterbury Farrel Foundry 
& Machine Co. This machine takes partly headed rivets or screw 
blanks after they leave the heading machine proper, and by means of a 
hopper feed, the blanks are automatically fed to the die in the reheader, 
thus making the operation entirely automatic. Automatic hopper feeds 
are of different types, but the usual form consists of a hopper into which 
the blanks are thrown promiscuously. They are caught by their heads 
in a blade which has a slot at the top, slightly wider than the body of 
the blank. This blade rises vertically through the center of the hopper, 
and as it passes through the mass of blanks, some are sure to be caught 




Fig-. 23. Double-stroke Solid-die Reheader Waterbury Farrel 
Foundry Make 

by their heads and are carried to the uppermost position, where there is 
an extension of the slotted inclined chute. The blanks slide down this 
chute, which may be seen between the hopper and the flywheel, Fig. 23, 
and a guard which passes over the heads of the blanks prevents any 
which are not in the proper position from passing. A transfer slide on 
a line with the dies supports a pair of fingers that pick a blank from 
the carrier slide and deliver it at the proper time to the heading die 
where punches do the reheading. The operation of the heading mechan- 
ism is practically the same as that of the standard heading machines; 
in fact some of the types of standard heading machines can be fitted 
with reheading attachments. To do this it is necessary to take off the 
cut-off slide and substitute a transfer slide for conveying the blanks to 
the die. The reheader here shown has a capacity for handling %-inch 
wire, producing from 50 to 60 rivets per hour. 

Cold-heading- Operations 

After describing the different types of cold-heading machines, the 
next step is to take up the work for which each type is best adapted. 



26 No. 119 COLD-HEADING 

By the process of elimination we can dispose of the open-die types of 
machines with the simple statement that, if the blank to be produced is 
over nine or ten diameters of the wire in length under the head, it must 
be made upon an open-die machine. There are, of course, exceptions to 
this rule, but they are so special that they need not be considered here. 
In general, open-die machines are faster than solid-die machines of the 
same size, as the open-die cut-off mechanism is simple and much more 
rapid in its action. A rivet or screw-blank made on an open-die ma- 
chine is easily distinguishable by light raised lines under the head and 
along opposite sides, caused by the metal being crowded into the crev- 
ices between the dies when the heading pressure separates them ever 
so slightly. The tools used in the open-die machines are more costly to 
make, and each set is good only for one particular length of rivet. In 
speaking of the wire in units of diameter, all sizes are included under 
the general rules. Thus, while only 1*4 inch of %-inch wire can be 
ejected from a solid die, 3% inches would be the limit when working 
%-inch wire. Similarly, when heading in the single-stroke machines, 
two and one-half diameters of any size of wire is all that can be put into 
a head. 

Single- stroke Heading- 
Excluding reheading, we have only the single- and double-stroke head- 
ing to consider, since the heading operation on solid- and open-die ma- 
chines are the same. It has been stated that the limit which may be 
reached w r ith a single-stroke cold-header is the upsetting of two and 
one-half diameters of the w r ire into the head. By this we mean that no 
matter how soft the wire is, nor how carefully it is cut off, an unsup- 
ported length of two and one-half diameters irrespective of the size is 
all that can be controlled by a single heading punch. If a larger 
amount of wire is left unsupported and struck by the heading punch it 
will buckle at the center and be forced over to one side. A typical 
single-stroke solid-die heading job may be seen at A, Fig. 24. The upper 
illustration shows the wire blank and the lower view the finished piece. 
At B, to the right, is a similar single-stroke heading job, but one which 
requires an open die machine on account of its length. Now, turning 
to Fig. 26, the action of the metal under the heading operation may be 
followed. In the upper illustration the blank is represented with the 
metal for the head, comprising two diameters, extending from the die. 
The four illustrations which follow are intended to convey an idea of 
the way the metal spreads under the advance of the heading punch. 
The heading punch is, of course, in this case recessed to shape the 
fillister head to be given the blank. It will be seen that we have 
here the same result as was obtained in our preliminary experiment 
with the hammer in the first chapter. The metal, when first under pres- 
sure, commences to bulge next to the die and continues spreading out 
until confined by the limits of the recess in the punch. At the right- 
hand side of Fig. 26 we have a similar single-stroke heading opera- 
tion taking place on a wire blank which was too long to be headed in 
a solid die. In this instance the head was oval,, countersunk in shape 



MACHINES AND OPERATIONS 



27 



and two and one-half diameters were upset in the head. This repre- 
sents practically the limit of a single-stroke heading operation. The 
flow of the metal is represented by the four illustrations within the 
brace, and the lower view shows the completed blank in the die 
ready for ejection. 

Double-stroke Heading 

It is on double-stroke heading operations that we find the most in- 
teresting as well as the most difficult work. Referring to Fig. 24, a 




D 





Fig. 24. Examples of Cold-heading from Different Types of Machines 

double-stroke solid-die product may be seen at C, and at E a double- 
stroke open-die product. The only reason for using the open-die ma- 
chine for producing the work shown at E is on account of its length. 
The head in itself could just as well have been produced on a solid- 
die machine of the double-stroke type. 

In all double-stroke heading operations the first blow, known as the 
coning blow, is used for centering and starting the heading opera- 



28 



No. 119 COLD-HEADING 



tion, and leaves the wire in condition to be readily finished by the 
second blow which does most of the work. Referring again to C in 
Fig. 24, the upper view shows the wire cut off, and in the center is 
shown the result of the coning blow. The punch which does the coning 
is shaped so as to "gather" the stock, tapering it at the end and allow- 
ing it to partially head next to the die, so that when the second blow 





Fig. 25. Some Applications of Cold-heading 

is struck the metal will flow naturally toward the desired shape. 
When the blank is cut off the end is apt to be "out of square" which, 
of course, means that more metal would be on one side of the head 
than on the other, and if struck without being centered, the result 
would be a "lop-sided" head. The limit of the double-stroke head- 
ing machine is the upsetting of five diameters of the wire. On certain 
grades of metal and by using extreme care this rule may be slightly 
exceeded, but a five-diameter head is very nearly the limit possible. 
In Fig. 27, at the upper left-hand corner, may be seen the wire blank 



MACHINES AND OPERATIONS 



which has been cut off and is in the die ready for heading. In this 
instance there are three and one-half diameters of the wire left pro- 
jecting from the die to be upset into the head. Directly below this 
may be seen a view which shows the result of the first or coning punch. 
The four views which follow show exactly how the wire upsets in 
forming the head, until at the extreme bottom is shown the completed 
blank, ready for ejection. On the right-hand side is shown the same 
series of views to illustrate the making of the head of a wagon bolt, 
which, because of its length, was made on an open-die double-stroke 
machine. 

Many heading jobs are performed upon a double-stroke machine that 
would seem to come within the range of the single-stroke machines. 



fe 



2 DIAMS. IN HEAD 




3-6 



2.5 DIAMS. IN HEAD 




>3 



ULT OF THE PUNCH 

Machinery 



Fig-. 6. Evolution of Screw Blanks made on Single-stroke Cold-headers 

The reason for this id that with the double-stroke machine the metal 
can be controlled to a higher degree of accuracy, and for that reason 
on accurate work the double-stroke machine is often used even though 
the head requires less than two and one-half diameters of the wire. 

Fig. 25 is shown to illustrate some practical applications of cold- 
heading. At F is shown a blank and a headed ball, such as is used 
in the ball bearing industry. Heading machine manufacturers have 
given special attention to the heading of steel balls, so that cold- 
heading is now the usual way of producing ball blanks. At G is shown 
a screw blank and a rolled thread screw, which illustrate a condition 
of thread rolling practice. When the screw threads are to be rolled, 
and it is still desirable to have the unthreaded section of the screw of 
the same diameter as the threaded section, the method of heading 
shown at H must be followed. In this section of the ilustration the 



30 



No. 119 COLD-HEADING 



steps in making a rolled thread screw of uniform size are shown. 
First we have the cut off blank; second, the partly headed blank in 
which the section which is to be left unthreaded has been upset 
enough larger to match up with the diameter of the thread which will 
be rolled upon the lower section. The completely headed blank is 
shown next, then the slotted head, and last, the finished screw with 
the rolled thread. Similarly at I are shown the successive steps in 
making a wood screw, and the manufacture of machine and wood 
screws like those shown forms one of the most extensive uses for cold- 
heading machinery. 



3.5 DIAMS. IN HEAD 




RESULT OF 2ND PUNCH 



'/, /////////{^-L\ 

j^:, EM 

'/Sy; j-l 



3.5 DIAMS. IN HEAC 




RESULT OF 2ND PUNCH 

Machinery 



Fig. 27. Evolution of Screw Blanks made on Double-stroke Cold-headers 
Reheadingr 

Reheading is a more important branch of cold-heading than is gen- 
erally recognized, and some of the "stunts" which may be accom- 
plished with the proper knowledge of reheading machinery strongly 
emphasize this fact. Reheading is usually necessary for one of two 
reasons; either to produce a head which would require too much work 
for the double-stroke machine to do, or to produce a head which is 
larger at the end than at the shoulders as in the case of hinge pins 
like those shown in Fig. 20. Even though the blanks are usually an- 
nealed before going to the reheaders, this operation is one which re- 
quires a great deal of force because the metal has already been com- 
pressed and is very dense before being reheaded. 

A good example of reheading work is shown at D in Fig. 24. The 
first two pieces represent the work of the double-stroke solid-die head- 



MACHINES AND OPERATIONS 31 

ing machine, and from this point, the blanks are handled in a double- 
stroke solid-die reheader. The third illustration from the top in this 
group shows the result of the first reheading operation, and a plan and 
side elevation of the completed piece is shown beneath. The diameter 
of the head is very great, as compared with the diameter of the 
shank of the rivet and it will be readily appreciated that four opera- 
tions were necessary to keep the metal under control and completely 
head the piece. 

For producing hinge pins like that shown in Fig. 20, an open-die re- 
header is necessary. This is really a very interesting job of cold- 
heading, as there are eight diameters of the wire in this head. Two 
operations are necessary to bring the blank A into the position shown 
at B and these operations are performed upon a double-stroke header. 
After this point, the partly formed blanks are annealed and finished 
in a double-stroke open-die reheader, producing the result shown at 
C in two additional operations. The hinge pin shown at the right- 
hand side is similar but smaller. 



CHAPTER III 



COLD-HEADING DIBS AND TOOLS 

In the first two chapters the principles and different types of cold- 
heading machines are treated, together with the character of work 
for which each machine was adapted. In this chapter we will consider 
in detail the tools for solid- and open-die machines, including an out- 
line of the operations connected with their making. As there are 
numerous little kinks and methods followed by individual heading 
die makers, it will only be possible to strike an average and outline 
the general processes of making the tool. As in other lines of tool- 




Fig. 28. A Pair of Solid Dies for the Cold-header 

making, no two workmen's ideas on a given set of tools will agree, al- 
though each may be right from his own point of view. 

Tools for cold-heading machines may be roughly divided into two 
classes those used in solid-die machines and those used in open-die 
machines Whether the tools are for a single- or double-blow machine 
affects only one extra tool, namely, the upsetting or coning punch. In 
all other respects the tools are similar. The chief difference between 
the tools for the solid-die and open-die machines lies in the dies them- 
selves, the punches being the same in both cases. Figs. 28 and 29 il- 
lustrate the difference between dies for the solid- and open-die ma- 
chines. Pig. 28 shows a die and punch for a solid-die machine. These 
tools are very simple, being merely sections of round stock, the die 
being made with a hole to agree with the diameter of the wire, and 
the punch with a cavity of the correct shape for forming the head. In 
Fig. 29 a pair of open dies, without the punch, is illustrated. In this 
case the wire is held between the halves of the die, and the cutting 



DIES AND TOOLS 



33 



off is done by the dies themselves, as was explained in Chapter I. 
Therefore a pair of dies for the open-die machine must be of exactly 
the same length as the finished rivet under the head. The dies shown 
in Fig. 29 were made for forming a carriage bolt having a square 
shoulder under the head. By referring to Fig. 30, a set of tools 
for a solid-die machine may be seen in place. These consist, in the 
case of a single-blow machine, of the die A, in which the wire blank 
B is held for heading; the punch G which shapes the head and is 
actuated by the ram of the machine; the cut-off die or quill Z>, which 
is similar to the heading die, having a hole through its length 
through -which the wire is fed against a feed-stop (not shown) the 
proper distance, and is then cut off by the cut-off blade E. The face 
of the cut-off die is crowned to help the cut-off blade do its work. 
Mounted on the cut-off blade is a carrier F that holds the blank to the 
cut-off blade so that it may be carried over to the heading die. A 





Fig. 29. A Pair of Open Dies for the Cold-header 

backing pin G fits in the hole in the heading die and regulates the 
length of the rivet under the head; it also serves as an ejector after 
the rivet has been finished. In Fig. 33 may be seen a set of heading 
tools, with the exception of the cut-off quill. These particular tools 
were used in making a round-head screw that required two blows to 
form the head. The die is shown at A; the second-operation punch at 
B; the first-operation punch at C ; the backing pin at D; and the cut- 
off blade without the carrier at E. At F may be seen the cut-off 
blank; at G the coned blank resulting from the first operation; and at 
H the finished round-head screw. If this same work were to be done 
in an open-die machine, the cut-off blade and the backing pin and die 
would be eliminated and a pair of open dies substituted. 

Making a Solid Die 

At first glance, the solid die appears to be simply a round piece 
of stock with a hole extending through it to receive the wire. There 
are, nevertheless, many points to be considered in making this die, and 



34 



No. 119 COLD-HEADING 



without the knowledge of them the tools would never work satis- 
factorily. The heading dies, punches and cutting-off tools are made 
from a good grade of tool steel, annealed stock being preferred. The 
tools are sometimes made of low carbon steel and then carbonized, and 
at least one large user of heading machines follows this method ex- 
clusively, but unless the best of carbonizing and hardening facilities 
are available it would be inadvisable. 

The length and diameter of a heading die are governed by the size 
of the machine in which the die is to be used. An idea of the pro- 
portion of the diameter to the length may be obtained by stating that 




Machinery 



Fig. 30. Section of Cold-header showing Locations of 
Principal Tools 

for handling wire up to % inch diameter, a die of % inch diameter by 
1% inch long agrees with good practice, and for handling % inch wire, 
the die may be 3% inches in diameter by 4y 2 inches in length. These 
dimensions are not arbitrary, but are, of course, determined by the 
make and size of the machine in which they are to be used. In Fig. 
35 is illustrated a little kink by means of which considerable die-steel 
may be saved. In this case a backing block is made to replace about 
one-third the length of the die. The dies themselves may thus be 
made correspondingly short, and as this pillar block is used beneath 
each die, one-third of the steel of each heading die is saved. 

Fig. 31 shows, in section, a typical heading die of the solid type, 



DIES AND TOOLS 



just made and ready for hardening. This die is given with actual 
dimensions so that the shrinkage allowances may be duly noted. The 
length of the die is 1% inch and the diameter % inch, and it is to be 
used for heading rivets from 0.105 inch wire. First, a hole a few 
thousandths under 0.105 inch diameter is drilled through the die. The 
die is then relieved from the back for a short distance with a No. 33 
drill, enlarging this section to 0.113 inch. A tapered reamer which has 
a taper of about 0.003 inch to the inch is then used to ream out the 
unrelieved section very nearly to the face of the die. At this point 
the die is hardened and this operation causes the mouth of the die 
to "open," leaving it about as shown in Pig. 32. Using emery and 
oil, the die is then lapped out from the back until the hole measures 





Machinery 



Fig. 31. Section of Solid Die, with 
Allowances for Hardening 



Fig. 32. Section of Solid Die 
showing Shrinkage in Hardening 



0.106 inch diameter, this being 0.001 inch over the diameter of the 
wire, allowing plenty of play for the working of the stock. 

The hardening operation is comparatively simple, the requirements 
being to have the die, especially the section adjacent to the hole, very 
hard. A useful kink to be followed in securing the desired hardness 
is illustrated in Fig. 44. This consists of a funnel shaped bushing 
which is threaded so that it may be screwed onto the ordinary water 
faucet. The die is brought to the right heat and held under this 
conical bushing and the water turned on full force. When the water 
is turned on, the face of the die and the hole receive a sudden quench- 
ing, giving it the extreme hardness that is necessary. 

The Punches 

Before a punch can be correctly made for any rivet except a "flat- 
head" a counterbore is necessary to obtain the exact shape of the 
cavity. In the case of flat-head screws or rivets, the punch consists 
simply of a length of round steel having a perfectly flat face with 



36 No. 119 COLD-HEADING 

chamfered edges. With round or flllistered head blanks, however, the 
finish punch must contain a cavity of the exact size and shape of the 
head. In making a punch like that shown in Pig. 33 for a round- 
head rivet, a reamer of the same semi-spherical shape is necessary. 
The reamer is turned up in the lathe, leaving a flat shoulder to limit 
the depth of the cut. The "half-type" reamer is employed, and is re- 
lieved only for a short distance behind the cutting edge so that a good 
bearing is secured while the punch is being reamed, resulting in a 
smoothly finished cavity. In hardening these reamers they are drawn 
to a straw color. In the case of difficult shaped heads, it is often 
found advisable to hammer a piece of lead into the soft die so that 
measurements may be taken and checked up with the sample. Weight 
forms an important feature in determining the amount of metal which 




Fig. 33. A Set of Heading- Tools and Work from a 
Double-blow Cold-header 

goes into the head. In setting up the machine, for instance, the tool- 
maker will often compare the weights of his rivet and the sample in 
order to see if the right amount of stock is being used. By cutting off 
the head close to the shoulder and weighing it, he can determine the 
amount of stock required, and by balancing the head with an equal 
weight of wire stock, he can readily determine the distance to which 
to set the wire feed. 

In the case of double-blow machines, in which an upsetting or con- 
ing punch is used, there seems to be no definite rule that can be laid 
down for the shaping of the cavity in the coning punch. As before 
explained, the idea of the coning punch is to upset the metal and 
leave it in condition for the final distribution into the finished head. 
Generally speaking, this intermediate shape is that of a truncated 
cone, the base of which is very nearly the diameter of the finished 
head, and the length of which is about two-thirds the amount of wire 
advanced by the wire feed. The top of the wire is left approximately 
the same diameter as the blank and slightly rounded. If a very large 



DIES AND TOOLS 37 

amount of metal must be put into the head, the angle of the cavity in 
the coning punch is made as obtuse as possible. 

It is customary to relieve the coning punch about as shown at C 
in Fig. 33, the object being to remove all danger of interference with 
the cut-off blade, because the coning punch strikes the wire blank just 
as the cutting-off blade releases it; therefore it helps matters to have 
the cut-off blade relieved as well as the coning punch. When the con- 
ing punch is to be used in connection with a countersunk die for flat- 
head screws, it is relieved about as shown in Fig. 38. By so doing, 
the wire in the cone is supported and driven down into the counter- 
sunk section of the die, instead of being left out at the line of the die 
face. There are so many governing factors bearing upon the shapes 
of coning punches that it must be left largely to the judgment of the 




Fig. 34. Reaming out a Coning Punch 

toolmaker. Punches for fillister head or other deep types of punches 
where the blanks would be likely to stick are often fitted with spring 
ejector pins as shown in Fig. 39. Ordinarily the die is the member in 
which sticking is most prevalent, but when the blank is short and 
the head is deep sticking will be encountered in the punch. 

In the manufacture -of very cheap screws, the slot in the head is often 
formed by the heading punch instead of being sawed. This means 
that the cavity in the heading punch must have a ridge of steel left 
standing to drive the metal down for the slot. To cut the cavity to this 
shape would be practically impossible; therefore the common practice 
is to hub the punch. The hub is made by turning up a blank of steel 
with a face of the same shape as the head of the screw to be pro- 
duced. A slot is then milled or filed in the center of the head of 
the hub, after which it is hardened and drawn to a straw temper. 
Before being hubbed, the face of the heading punch is first convexed 
so as to leave the highest point at the center, thus providing enough 
stock to make a well formed cavity. The tendency is for the metal 
in the punch to sink away from the slot in the hub; therefore by 



38 



No. 119 COLD-HEADING 



leaving an excess amount of metal at this point, the slot is completely 
filled when the punch is hubbed. After being hubbed, the punch is 
faced off, of course, and the sides turned up for hardening. Fig. 36 
represents the hub and the punch-blank before hubbing and Fig. 37 
shows the hubbed punch before being faced off. 

The Cut-off Tools 

The cut-off die is simply a section of round stock having a hole ex- 
tending through it slightly larger in diameter than that of the wire 
being worked. On small sizes of wire, 0.001 inch provides sufficient 
clearance. The face of this die is crowned slightly so that the cut-off 
blade which works in conjunction with it may act without binding on 
any other part of the die face. The cut-off blade is shown at E in Fig. 
30, from which it will be seen that the end is filed out U-shaped, so 
as to partly enclose the wire, thus supporting it while the cutting-off 











- | 
















2H. 


pL_jfe=j 

i 1 










Machinery 


Fig. 35. A Kink for Fig. 36. A "Hub" and Fig. 37. Punch after 
saving Die Stock a Punch Blank hubbing 



operation is taking place. A spring-finger F is fitted to the cut-off 
blade that snaps over the wire when the cut-off blade advances for 
cutting and holds the blank so that it can be carried to the heading 
die. There are different methods of applying the spring-finger or 
carrier, but a good way is illustrated in Fig. 30. Here the spring 
pressure is supplied from the spiral spring over the stud near the 
center, while the pin at the end operates in an enlarged hole in the 
finger serving merely as a guide to prevent the finger from swiveling. 
Both cut-off die and blade are hardened and drawn to a straw temper. 
There is little to be said about the backing pin which is shown at Z> 
in Fig. 33 except that as it receives the full force of the heading blow, 
it must be hardened and drawn to a very dark purple. 

Tools for Open-die Machines 

The only explanation required for tools for the open-die machines is 
the operations connected with the making of the die halves. These, 
which are illustrated in Fig. 29, are made by shaping up square sec- 
tions of tool steel to fit the die-holding block of the header. The 
halves of the die are left large enough in size to allow for grinding, 
and down the center of each face is milled a half-round groove of a 



DIES AND TOOLS 



39 



size slightly less than the diameter of the wire which is to be handled 
in the header. After the bulk of the stock has been milled out in this 
manner, as shown in Fig. 43, the halves are clamped in a special holder 
illustrated in Fig. 41 and a reamer of the proper size is run through 
the hole, taking half the stock from each die face. Set-screws are pro- 
vided on the die-holding box to clamp the two halves together and 
take up end play while this operation is being performed. Each of the 
four pairs of faces is treated in this manner and, of course, they are 
marked so that they can be mated readily. The object of having all 
four faces grooved is simply to make use of the other three sides of 




Fi S .33 




Fig.39 



Machinery 



Fig-. 38. Coning Punch relieved to force Wire into the Countersunk 

Head of the Die. Fig. 39. Spring-pin in Punch which 

facilitates Ejection 

the die; thus as soon as one pair of grooves has worn out of round, 
the dies are simply turned to bring a new pair of faces into use. As 
was explained in Chapter I, the object of chamfering the corners 
of the die halves is to facilitate the opening of the dies by the 
spring-finger on the machine. Fig. 42 shows the manner in which 
the square section of a die for producing a carriage bolt is machined. 
This square section comes under the head of the bolt and, therefore, 
must be provided for in the dies. After reaming out the grooves in 
the die faces the square outline is marked on each of the faces of the 
die, and the lines scribed for the depth. A starting point is made by 
chipping a groove at the proper distance from the face of the die, and 
the rest of the stock is removed by a square shaper tool, thinned down 
at the face to permit of its starting in the chiseled groove. Each of 



4u 



No. 119 COLD-HEADING 




DIES AND TOOLS 



41 



In grinding the sides of the die halves, the stock taken off permits 
the faces to come together far enough to flatten the circular opening 
in which the wire is held. This provides the necessary clearance for 
gripping the wire. 

Multiple solid dies are often made for the sake of economizing in 
steel. Examples of such dies are shown in Figs. 45 and 46. The die 
in Fig. 45 has three openings so that after one of them has been worn 
out of round, the die may be moved along in the special holder neces- 
sary to hold a square block and another hole put into use. If the 
work is such that the die can be made without clearance, the block 




Fig. 43. Milling the Grooves in Open Dies 

can then be reversed and the opposite ends of the three holes used. 
Similarly, in Fig. 46 is a multiple die of hexagonal shape, providing 
eighteen working openings. As a general rule, however, multiple dies 
are not used, because of the trouble caused by special die-holders. The 
plan of reversing the die to use the opposite end of the hole has dis- 
advantages on some work where the heading blows close the hole in- 
somuch that the necessary lapping out makes the method more trouble- 
some than beneficial. 

Setting--up for a Plain Heading- Operation in the Header 
In setting-up in a solid-die header, the first step is to put in the cut- 
off die and adjust the cut-off blade. The blade is adjusted by snapping 
the finger over the wire, and while thus held it is clamped in position 
against the cut-off die. The die is next bolted into its seat and the 



42 



No. 119 COLD-HEADING 



backing pin adjusted to size the length of the rivet under the head. 
The finish punch, in the case of a double-blow machine, is then located 
in the punch-holder. The coning punch is next held in the punch 
holder, and, if necessary, it is adjusted to bring its face into line 
with the finish punch. The finish punch should be set without back- 
ing or "shimming" of any kind, but if necessary the coning punch 
may be shimmed up to agree with it. The stroke is then ad- 
justed so that the punch faces almost touch the die face. After this, 
the wire feed may be set and the machine is ready to be operated. 
On every job there is more or less adjusting of the feed, grip and ram 
movements to obtain the exact results. 

In setting up the tools on an open-die machine there is, of course, 
no cut-off to be taken into consideration other than the prrper setting 






O 
O 

O 



ID 



Machinery 



Fig. 44. A Method of 
hardening Solid Dies 



Fig. 45. Multiple Die 
cf Square Type 



Fig. 46. Multiple Die 
of Hexagonal Type 



of the die halves, as the cutting is done simultaneously with the move- 
ment of the dies. The operations of setting up the punches on the 
open-die machine are the same as on the solid-die machine. 
Special Ball-heading- Machinery 

The E. J. Manville Machine Co. makes a special type of header 
adapted for forming ball blanks. The cold-header is an important 
adjunct to ball making. The principal feature is positive ejection for 
the ball blanks after heading, because ball headers operate at a very 
high rate of speed and positive ejection is absolutely necessary. A 
secondary advantage of this machine lies in its ability to handle posi- 
tively the short ball blanks. 

Fig. 47 shows a vertical longitudinal section taken through the 
working parts of one of these special ball headers. A is the frame or 
bed of the machine; B is the die-block of steel; C is a hardened tool- 



DIES AND TOOLS 



43 




44 No. 119 COLD-HEADING 

steel backing block for the die D; E is the backing or knock-out pin 
which backs up the smaller knock-out pin F; G is a cast-iron bracket 
screwed onto the under side of the bed to hold the adjusting screw H 
which raises or adjusts the die-block into the correct position for 
heading. A lock-nut / insures the adjustment. J is a tool-steel punch- 
holder having an enlarged head w r ith a set-screw K for holding the 
punch L. The body of this holder is of smaller diameter than the 
head and is made a sliding fit in the bushing M. The holder is 
normally kept in its forward position under spring tension by means 
of the coil spring N. Two adjusting nuts are on the back end of 
the holder. P is a small hardened tool-steel ejector pin, which is also 
kept under a spring tension, and is backed up by the bar Q that passes 
through the round rod R and is pinned in place. 8 is the punch-slide 
that carries the punch-holder and other parts shown and is adjusted 
by the screw T. The punch-holder is backed up by a solid block U that 
acts as a buffer as well as a filler between the holder and adjusting 
wedge V. W is a bar cast in the bed between the two sides carrying 
the adjustable bracket X that has the stop-pin Y and adjusting 
screw Z. 

The action of the machine is as follows: The round bar or wire 
is fed in and cut off in the usual manner, and the cut-off blade carries 
a blank over to the heading die, but as there is no shank to be pushed 
into the die, as is the case with a longer blank or rivet, as soon as it 
is carried over, the gate or ram advances, and also the pin F. As pin 
P is under a spring tension the blank is very quickly seized between 
the two pins, and held in position until the gate has advanced far 
enough to hold and squeeze the blank into a ball. 

After this the gate returns and when it has reached a certain po- 
sition the bar or trigger Q strikes the pin P that acts as a knock-out, 
and ejects the ball if it clings to the punch; if it clings to the die the 
other ejector pin F ejects it. 

It will be noticed that the pins F and P are not long enough to reach 
to the ball arc when under the heading pressure; this leaves slight 
projections on the two sides which can be removed easily, whereas if 
the pins were even slightly too long there would be flat spots left on 
the finished balls. 



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UNIVERSITY OF CALIFORNIA LIBRARY 

. 




MACHINERY'S 

HANDBOOK 

For MACHINE SHOP 
AND DRAFTING-ROOM 



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MACHINIST. 



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