US1748503A - Apparatus for producing cap screws and the like - Google Patents

Description

. I k v i I I I 3 5 I n 5 'flfifla I Feb. 25, 1930. WAYNE 1,748,503

APPARATUS FOR PRODUCING CAP SCREWS AND THE LIKE Filed Npv. 4, 1926 4 Sheets-Sheet 1 avwenboz Feb. 25, 1930. G. H. WAYNE 1,748,503

' APPARATUS FOR PRODUCING CAP SCREWS AND THE LIKE Filed Nov. 1926 4 Sheets-Sheet 2 Feb. 25,1930. H, W Y 1,748,503

ARATUS FOR PRODUC NG CAP SCREWS AND THE F'il Feb. 25,1930. v v a. H. WAYNE 1,743,503

APPARATUS FOR PRODUCING CAP SCREWS AND THE LIKE Filed Nov. 4, 1926 .4 Sheets-Sheet 4 I avwwntoz 951 A flaw/" W gas 1 Patented Feb. 25,1930

. ITED sr Q GLENN'H. WAYNE, or WATERBURY, CONNECTICUT, ASSIGNOR ro" sCovILL MANN- TETS PATE NT-"JQOF-FICE1 1 FACTURING- COMPANY, OF ATEN URY, CoNNE 'riCU'r, A COBPORATIONOF CON:

APPARATUS-FOB raonuome AP SCREWS AND THE LIKE I Application filed November 4, 192e. seriaiNo. 146,039. 1

,This invention relates to apparatus for producing; cap screwsand ;the like.

Cap screws as known in the trade ordinari-i 1y comprise a'heXagonal,-fil1ster,flat or round head, a' threaded shank and an unthreaded portion between the s'hank and head which may be termed a shoulder. This shoulder has of smaller diameter is rolledibetween two a diameter-equal to theoutside or crest diameter ofthe threaded shank.

According to knownpractice a blankhavinga shoulder of final diameter andas'hank' V threading dies to thread the During' this threading operation a burr is. formed beyond the final turn of thethread and thisv burr is then rolled down to shoulder diameter .by means of planishing blocks; I

Apparatus for thread rolling asjheretofore known includes vertically mounted thread-Q ingd-ies having, above the serrated portions; plane surfaces Corresponding to theshoulder .Of thebm k. [These-surfaces are so dimensioned that the blanks can be suspended fromthe edgesof the die blocks to properlyposition them for the thread-rollingoperation, In the case of "ordinary, commercial cap' screws, the shoulderfor agivensize screw has a given length but thetotal length varies in accordance with commercial requirements. so

In thecase of special standardsrequired by the trade,"'however, the thread length for a i I screwxofgiven diameter is constantso that the shoulderlengthvaries with the total length.

" It is'an objectof the present invention to provide improved apparatus capable of efiecti jely and economically producing cap screws by thethread-rolling. method.

f In the drawings l i .7 i Figure 1' is a top'plan view of apparatus for {It is a further object f provide apparatus of, the type mentioned/for effectively and economically producing 7 cap variousforms screws having. various shoulder lengths. c With-these general ob ects, and others, 1n View, the, lnventiongfconsists,1n the features,

combinations, detailsof construction and ar-' rangements of parts: which vwill'fir'st be described in connection with the accompanying V drawings and then pointed out particularly inthe Claims.

the invention to and,

ance with the invention; I Figure 2 is an end vi shown inFig. 1; 1

Figure?) is aface' view of a threading die and planishing die in assembled relation;- Figured is an edge view thereof; d:Figure 5'; is an end view of ,th plani 1e; 1 Figure Gis. an end view ot the threading Figure portionofthe threading die; Figure'8 is a view taken at 'producingcap screws constructed in accordvthe die threadsandfthrough the blank after thethreads have been form'ed upon the blank dies and also showing the planishingblooks in operation; r

' Figure '11 is mediate blank; a Figure 12.is ,a similar view of theblank threaded but unfinished; i f

Figure 13 is a similar view ofithe finished. product; V i

Figure I and a combined positioning and p'lanishing vention; I.

Figure 15 is an edge view th l' f s i g tions; 7 I A Figure 16is an end view o'fthe'die and poright angles: to v 7 is anenlargedsectional view .ofa

14 is a face viewof a threadingdie butibefore the planishing operation'has been" performed; J .11. V,

Figure 9 is a similar viewbutshowing both ,'Figure 1.0 1s a side view of a-rough blank; 1

a similarfview of aninter- 86 die in accordance .with one form'of. this inp sitioning andplanishing block shown in 14.1nounted-inthe apparatus o t -Figs 1 and 2;

Figure 17 and1 8 are perspeotive'views-ofdies. 1 ,1

Referring to thedrawings, Fig. 13"-illustrates one example of-a finished cap screw.

of positioning and planishingy comprising a shank having athreaded'por tion 22', an 'unthreaded shoulder 23',and ahead 21. The apparatus hereinafter described is capable of produclngsuch cap screws,- having shoulders. ofttrue diameter and of proper finish and in which thethreads terminate ance and strength, a cut-thread product.

According to the present invention, briefly stated, a blank is so formed and the blank is v so threaded that the final turn of the thread adjacent to the shank has full crest diameter.

Beyond the final turn of the thread the metal of theblank is upset in the form of a ridge or burn which, after threading, is removed.

And at some stage in the procedure the shoulder is machined to size. In carrying out the invention according to what isnow considered the best plan of operation, the shoulder is machined before die-rolling, and the burr is worked into a prolongation of the shoulder to carry the shoulder down to a thread turn of full outside diameter.

In carrying out the invention, along the lines stated, the finished product referred to maybe formed from a rough blank such as is shown, for example, in Fig. 10. This blank has an unfinished round head 21%, a shank 22, and a rough finished shoulder 23 which is somewhat oversize as to diameter and undersize as'to length. Between the shank and shoulder is a bevel 24, hereinafter more fully referred to. This blank may be formed in any suitable manner, as by forging from round: stock in a heading machine. The head .21 is finished, as by milling or'die-cuttting, to

form the desired head. a Fig. 13 shows a filister head but the head may be polygonal, fiat or round, the headfinishing being a wellknown operation and formingno part of the present invention. The shoulder 23 is mas chined, i. e.cut, to true final diameter, thus giving it the desired finish and accurate size. This machining of the shoulder may convenientl v be done when the head is machined to trim the top and bottom. thereof.

The above described operations provide what may be termed an intermediate blank,

such asillustrated in F ig. 11. This intermediate blank has a finished head 21", a shank 22 and a shoulder 23 which is finished tothe -wil'l be thrown outwardly in rolling the final diameter but is somewhat undersize as to length. The total length of the intermediate blank is approximately the length of the screw when'finished. The difierence in diameter between shoulder and shank equals the amount by which the metal of the shank Between shoulder and shank is a The angle of the bevel and the dethread. bevel 24".

ficiency in stem lengthare hereinafter re ferred to.

This intermediate blank is die-rolledto thread the same, the threading extending alongthe shank and part way up the bevel, the extent being hereinafter more fully referred to. Thisdie-rolling operation is such as to upset the rolled metal into the form of a thread, The metal of'the blank is caused to flow outwardly to form the thread crest, the

outside diameter of which is approximately that of the finished shoulder. During the rolling operation described, only that part of the blank that is to be threaded is die-rolled, the shoulder and upper part of the bevel being left free. During threading, some of the metal of the bevel of the blank is caused to be upset and displaced outwardly into the form of a ridge or burr beyond the final turn. of the thread.

Fig. 12 illustrates this stage of the production. The uncompleted' screw there shown has a threaded shank 22 and an unthreaded shoulder 23". Beyond the final turn of the thread, adjacent the lower end of the shoulder is a ridge or burr25 slightly greater in diameter than the shoulder. The shoulder, for the most part, remains unchanged but there may be av slight, enlargement of its lower end due to the crowding of the metal in forming the burr. Should this occur it is corrected when the burr is removed, as later described. t

The invention in its entirety includes two complementary threading dies between which the blank rollsas the thread is formed. As shown as an example in Figs. 1+7, slidable in. upper and lower tracks 31, 32 of a bed block 33 is a slide 34 having a die-carrying portion 35. This latter carries a flat, substantially rectangular die block 36 which rests on a ledge 37 of the carrier and is secured in place by means of clamps 38 and bolts 39.

'The outer vertical face of the die blockhas a series of threading teeth 40 hereinafter referred to. To reciprocate the die block 36,

in the embodiment here illustrated, secured to'tl e slide 34 is the end of a pitman 41 driven from a rotary disk 42 by a crank pin 43 mounted therein. Disk 42 isconnected with a gear 44 meshing with a pinion 45 on a drive carried by the frame or bed block is an adjustably mounted supporting block 51. This block has a ledge 52 on which is supported a, die block 53 heldin place by clamps 54 211K bolts 55 and arranged-on a level with die 36 (Fig. 2). The outer vertical face of the die block 53 is formed with a series of, parallel rectilinear teeth 56 running. endwise of the block but at an angle to the longitudinalaxis thereof. The teeth 40 of die 36 are similarly arranged, the teeth of one die, however, being opposed to the intervening grooves'of. the-other die, As will be understood by those skilled in the art, the angle of the die teeth 6 V with respect to the liHeof-traveI of the blank,

governs the lead of the thread formed; In

theapresent embodiment,- the vtwo die blocks are located substantially parallelf and so spaced apartthat the toothcrests are separated by a distance'less than, and the groove bottoms by a distance 'greater than, the di- I a'ineterof the shank of theblank to be threaded. I That is, the groovebottoms, which. determine the thread .crests,;are'- spaced aparta "distance'approximatelyequal to the diameter 7 of'ithe desired product," The position of die block {36 maybeadjusted by the use of shims.

' Die block 53 may be adjusted by adjustment of the supporting block 51 by means ofbolts 57 and by the use of shims. In the'embodiment shown, the die blocks are formed with teeth on both faces'so that the blocksmay be reversed as one setof teeth wears out but,

for the purposes of the present description, only one toothed face need be considerd. To facilitate the entrance of the blank between thedies,vthe opposingends are sloped or roundedoif as appears in Fig. 4, giving, in effect, a bell mouth entrance for the blank. f :In. the apparatus here shown as an ,example, the ends'of the die teeth along the sides of the dies toward the blank head-or what may be termed thetrailing ends of the die teethare ground or chamfered ofi at an angle to theplane of the tops of the teeth (Figs. 6, 'Zand 8). While one purpose of'so' chamfering the dies is to prevent the teeth I o from chipping and breaking off at the trail structioncooperates conveniently with the bevel of the blank in the formation of the ing ends during threading, -such a die condesired product. I I mWith'the movable diedrawn back to the end of its idle stroke 1), a blank is pofsitioned adjacent the opposingends of the complementary-dies. It will be apparent that theblank must beso positioned above the die teeth that the shoulder will be bjeyond thei teeth. The reiis provided' means for fixing theposition'of the blanks with respect to the i (die teeth. This may be accomplished, for,

. example, by a pair of complementaryledges associated with. the die teeth and onwhich "the blank heads may, be suspended, these ledges being so arranged, however, that .the

blank shoulders' are left freeduring th rolling. In vthe embodiment -illustrated in "Figs. 1 7-, the ledges'are formed as part of the two die blocks. To thisend, die block 36 extends beyond the line of termination of the f chamfered teeth-so that its top-cdge-formS a ledge for receiving the head of-a blank.

- I The die blankr53 is similarlyformed to provide a ledge 61. These-complementaryledges receive the. underside of the head of the blank which is {thus suspended=.-between; the die blocks- {The ledges 60, 61 are: spaced from the line: of termination "of their respective I die teeth a }distance to cause the blank-to;

beso' positioned with respect to the die teeth that the desired point ongthe blank comes I opposite the line of 'termination of the teeth. I

As is known to those skilled inthe art, there is a tendency for the blank to jump endwise in the. direction of its head when theteeth take hold. Consequently, this jump is allowedfor. The amount of jump for a given I set of dies being'known, the ledges 60, 61 are spaced from the teeth accordingly. The ledges initially position the blank, which then jumps and thereafter it is 'held'in the same relative axialposition byithe inter-engage merit of the di e teeth and the formed thread.

Due to the extension. of the die blocks 36, 53 to form the ledges 60, 61, the die blocks have plain surfaces '62, 63 that come opposite bevel. These plain. surfacesare soformed that when the die blocks are inposition the plain surfaces 62,- 63 are spaced apart a distance substantially greater than the-diameter the shoulderof the blank and part of the of the shoulder of theblank. In terms-of one. die, its plain surface is located below the plane-0f the bottom of the die teeth (Figs. 7 and 8). Consequently, during the thread-rollingthe shoulder of the blank is left free. In otherwords, the surfaces 62," I

63 playno part in the threading operation except in that the ledges60, 6 1 initially position the blanks. I 1

A. blank being suspended in position, as a above described, the. moving die 36 is ad vanced and the blank is rolled between the two dies. Thatis, the blank revolves on its between the dies own axis and travels along I I I as the moving die advances.- For a half turn of-Qthe' blank the teeth of die 36 form thread v v teeth digging into the metalto 'form the threadgroo'ves and displacing the metal outwardly into the die grooves to form the thread crestmDuring the next halfj turn of the blank thehalf thread portions formed by die 36jarepresented to die 53 and the half thread portions formed by .die are presented to die 36 for further formation 7 or finishing orzboth. 1 With the apparatusdescribed, "the complete thread, is roughly" ",formedduring the first, half turn or few half:

portions in half the surface of the blank and theteeth of 'die 5 3 form thread portions in v the other half of the blank surface, the die I turns of the blank, the remainder of the action'being 'inthe nature of a finishing or planishing foperation. Duringthis thread-,

ing operation, the chamfered portionsof the die teeth, acting on the. bevel of the blank,

thread partof the sameyand upset some of the metal into the form of a ridge'or burr beyond the 'finalturnof the threa'd'.- Fig, 8

grooves to form the thread crest. Fig. 8 also illustrates how the-chamfered ends of the die teeth have threaded part ofthe bevel and have upset the metal into a burr 25 beyond thefinal turn of the thread.

The invention in its entirety includes platens for rolling down the burr to stem diame ter, these platens being freely separated from and independent of the threading dies. The

platens may, for example, alsobe formed as part of a second die block having'a spacing portion and a platen portion. In the exemplifioation illustrated in Figs. l-9, there is provided a pair of complementary platen die blocks 72, 73. These are rectangular blocks of the same height as the threading die blocks. The platen die block72 is mounted alongside of threading die block 36 and the platen die block 73 alongside of threading die block 53. The two platen die blocks are held in their respective die carriers by clamps 7d and 75 like the clamps which hold the threading die blocks and may be adjusted by shims. At the top of platen die block 7 3 is a platen 71 (Figs. 3 and 4) formed as a part.

of the block, being thicker than the remainder of the block. This platen has its front face substantially in the plane of the bot toms of the grooves of the adjacent thread ing die. In width, i. 'e., vertical width, the platen extends down'to a line substantially below the line of termination of the teeth of the adjacent threading die (Fig. The platen length is sufficient to enable it to act on a blank during one or more revolutions thereof. The remainder of block 7 3 is a spacing portion. That is, it serves to space the platen portion from the ledge of the die carrier.

Die block 72 is an oppositely facing duplicate. That is, it has a platen portion 70 like platen 71 and a spacing portion like that of block 73.

When the two platen die blocks are opposite each other (Fig; 9) the platens 70, 71 are spaced apart a distance substantially equal to the diameter of the blank shoulder.

As appears in Fig. 3, when the platen blocks" are in place the-platens'are in line with the plain surfaces 62,63, but they are wider than the latter by. the widtl' of several die teeth. That is, the platens are arranged to come opposite the blankshoulders and several turns of the thread. The platensurfaces are arranged parallel to the plane of the tops of the teeth except that they are slightly sloped off (Fig. 4) at theend toward the die blocks to facilitate entrance of the blanks. V

As the slide 3% moves across carrierbl, and near 'the end of the stroke, platen 70 moves across platen 71 and part of the blank is rolled between them (Fig. 9). rolling operation the upset metal of burr 25 is rolled down by the platens, the displaced During the metal being received by the final turn of the thread That is, the metal is worked into the shoulder to prolong the same,'carrying the shoulder down to a thread turn of full outside diameter. If the shoulder. 23 of the partly formed blank is increased in diameter'as above referred to, it will have true diameter after the rollingby the platens. F

Except in positioning the platens, the blocks 72, 73, other than the platen portions play no part in the operation. As the distance separating the faces of the spacing p'ortions of the blocks is greater than the diameter of the blank they obviously do not touch the blanks.

9 illustrates the relation of the parts near the end of the platen action. The burr 25 has been rolled down, the displaced metal being received by the final turn of'the thread and elongating the shoulder, which extends down to a thread turn of full outside diam eter.

It is considered advisable to have the platens extend downwardly some distance beyond where the burr is encountered. Theoretically the platen surfaces are tangential to the thread crest but if it is found that the platens tend to flatten the thread crest, the platen surfaces may be ground oif adjacent the lower edges to avoid this.

As the moving die reaches the end of its rolling stroke the blank reaches the endof the stationary die and can drop out, to be collected as desired. The moving die then makes an idle returnstroke to'initial'position,thus completing the cycle of operations for one blank. V

. Referring back to the blank, it is noted that the bevel 24 above referred to need not necessarily be a true bevel. That is, the surface may be frustro-conical or may be slightly rounded. WVhat is desired is a gradual step down from shoulder to shank of such dimension that the dies will upset such a burr as can'be worked into the shoulder to prolong the same as described. For-convenience, however, the term bevel has been used. The angle of the bevel is not the same for all blanks. Generally speaking, the angle of bevel varies with the diameter of blank and with the depth of thread to be formedi As it is difficult, even with these values known, to fix a standard, it is considered advisable to adopt a givenbevel and make'a trial'run. .It has been-found that for screws varying'in diameter from 1/ to 7 /8; a suitable range of included bevel angles is' from 20 to 30. This range provides a starting point for a given production run, correction being made it necessary, after a trail run, as later described. As the diiferencein shoulder and shank diameter for a given size screw and given dies is fixed, the fixing of the bevel angle, of course, determines the-axial length 7 of the bevel.

150 I I While the shoulderof" a given standard ing thedieteeth to change thefangle'of 'cham The angle of chamfer 'of the 'die teeth varies, generally speaking, with the. angle'of Q the bevel. Forthe-above mentioned range 'of'screws, a suitablelrange of chamfer angle 1 is 259 to As a starting point fora given run, the die blocks are convenientlyformed so that-the blank is positioned in rolling to 1 cause the "threading to extend about two I thirds of theway' up the bevel.

' 1 As anexample, the] following'dimensions and relations have been found Suitable for the production'of 1/2. stee1"cap screws, all figures being approximate '--Diameter o-f shank'o f blank ('22), 7 16".

i Width of pl ainsurfac'es (62, .63) separat- Diameter of shoulder-(after machining) Axial length or bev1 j,(24), 5 32"; (This I Length of shoulder of screw produced (23) at opposite point in circumference, 1/2" size should have Tthesta'ndar'd length at all i points, aslight overl ength"ztt'sorriepointsis A i V 1 products.

immaterial. Variation, such as that above mentionedfrom agivenI shoulder length to a slight overlengthis alsofound in cut thread As unknown variables, such, for example,

as 'the nature and condition of the stock.

amy. cause a slight deviation in' results, it may be necessary to make a readws'tment following atrial run, (This may befdone,

for example. by changing the angle of the bevel of the blank andof the 'chamfer of the dies, if they are chamfered. 'Orit may be 'accomplished by a variation in the axial posi tion of the blank with respect to-the die teeth. That' is, if the bevel of the blank istoolong for a," given die,'too great aburr is formed. This may be corrected by regrindfer, or by using other blanl zsg If the bevel of the blankis too short fora given die, there is not enough of a burr formed; This may be corrected vby new dies, new blanks, or by grinding down the ledges of the dies (60, 61) so "as to so position the blanksthat the thread- 7 ing extends further up the bevel, more metal 6 z thus being upset into the burr.

With the apparatus describ d it is possible to utilize the economicalstep of threading the 'blank by die-rollingat the same time producing a cap' screw that has the appean an'ce and strength'of a cutethrjead 3roduct.: Further, the partsdescribed permit thread rolling and' planishirig in ta-0a 'a sagetr. the blank and, as threading. dies wear out, the same platen blocks maybe used, it being nee:

'essary to make new dies only. Further, the threading dies shown are economically cut,

being plain rectangular blocks. Y 2

" The'embodimentof the-{invention above 7 described is particularlyad'aptable to producing the. ordinary trade pro'duct,"abiove referred'to, in which the shoulders have.

given length forgiven sizes, theshanksvary- 'ing in length. i A given pair of dies may pro duce cap screws of any total length upto the width of the dies, the shoulders, however, being necessarily of the same length.

illustrated in Figs. 1fl'18 inclusive, particularly' adaptable to the production of, cap

' A further embodiment of the invention is 1 screws of the special trade standard above referredto, i. egin which the screws of a given length varies, the length of the shoulder must varyp V" In the; embodiment referred to, provision is'lmade' for a variable.blank-positioning means for a given "threading die. As here shown as an example,.a thread ng die is provided which is generally like the die 36 and diameter always have the same'thread length regardless of their total length- In thejcase of these screws, therefore, as the total isadapted to be moun'ted by clamps 38 [(Fig. 3 I

16) in-the same machine as above described;

Separate blank-positioning blocks of differ ent heights are provided' so that when the machine is used to produce a screw ofone ice I given length, one size of theseblocks islassociated with the threading dies and when another'length of screw is to be'produced another set of blank-positioning blocksis' substituted. This permits; using the 'same' threading dies to produce screws in which the shoulders have difierent lengths. fThe die comprises a generally rectangular block 101 (Figs. 14 and 16) of substantiallylthe same thickness as die 3b..v The block has are, similarly chamfered. the -rear'end of the die blocklOl the top and bottom faces are r'abbeted (Fig. 14) for a purpose later described. A" complementary die 102 is pro vided having teeth like die block 53, similarly' chamfered. This die'block is also rabbeted on: its top and bottomfa'ces. In the die blocks 101, '102, the blocks terminate at the chamfers. In other words, the :die blocks haveno extension 'along'their upper sides formingledges as in the case of the dies pre viously described; i Thereareprovided platen means for rolling down the burr formed during threading 1 and separate'mea'ns capable of'substitution p lfl't 7 width sufficient for the screw to-be produced. and in length it equals, as 'shown, the threadingf die 36 plus the'plate'n' block. The die 101 is formed with threading teeth inthev same manner as the-die 36 and these teeth for positioning the blanks'with respect to the dies. This may be conveniently acco1nplished by interchangeable blocks independent of the threading die and combining both positioning ledges and platens.

In Fig. 17 is shown a block 103 provided for this purpose. It is arranged to fit over the threading block as shown inFig. 14, the rabbeted part of the top face of block 101 engaging the rear enlarged portion of block 103. The two blocks are held in the machine by clamps in the same manner as the die blocks 36 and 53 were held. A similar block 103 is provided for die 102. It will be seen that the portion of the blocks 103, 103 to the left of line X-X are blank-positioning portions and that the parts of .the blocks to the rightof line XX are planishing portions. As shown in Figs. 1-9 inclusive, the planishing blocks or dies are spaced apart a distance equal to the diameter of the stem so as to roll down the burr formed in threading. On the other hand, the blank-positioning portions of the dies shown in those figures are spaced apart so that during threading they will not make contact with the stem. Inother words, the blank-positioning portions and the plan. ishing die are not in the same plane. In the form of block shown in Figs. 1418, inclusive, it is noted that the faces of the blocks 103, 103 are plane surfaces. Consequently, the blocks 103, 103 are slightly shifted in the horizontal planeso that, their outer faces are inclined to the line of travel of the blank, the pivot point being somewhat adjacent the line XX (Figs. 14 and 15). Consequently, during the threading operation, the shoulder of the blank will not be engaged by blocks 103, 103*, to the left ofline XX but, when the blank arrives at a position near the line V XX, the stem will be engaged by the slightly converging faces of the two blocks (to the right of the line X -X), so that the burr will be rolled down as the blank finishes its rolling movement.

It is to be noted that'block .103 mayalso be positioned in a similar manner with respect to the lower face of block 101, the rabbeted part of the latter being provided for proper fitting. This permits of die 101 being used in reverse position. 7

. Figure 15 shows the angular relation between the blocks and the positions of the cap screw 22 during the threading and planishing operations. It will be apparent that the angular shift given the blocks is'only slight, the

precise angle being found by experiment.

If desired, the blank-positioning and planishing blocks may be made in two parts, the line of division therebetween extending along line XX. For convenience in manufacture they are preferably formed as one.

In Fig. 18 shown a block 104 having a blank-positioning portion 105 whose width is different from thatof block 103. This block,

and its complement, may be substituted in placeof blocks 103, 103 when it is desired to alter the overall length of cap screws, while maintaining the length of threaded shank the same. That is, when it is desired to thread other blocks, such as blocks 10 1, are substituted. Blocks 104C, for example, being smaller as to vertical height than blocks 103, 103, serve to properly position a blank having a shorter shoulder with respect to the die teeth. With this construction cap screws having dif ferent shoulder lengths maybe threadedin the same dies merely by substituting different positioning blocks. 7

The operation of the apparatus will be clear from the above without further description.

lVhat is claimed is: I v v 1. In apparatus of the class described, and in combination, two complementary threading dies for threading acap screw blank and causing, during threading,;the formation of a burr on the blank beyond the-final turn of the thread, two complementary planishing dies for rolling down said burr and working the metal thereof into the shoulder of the blank to elongate it, said pla-nishing dies being .freely separable fromthe threading dies, and

means for causing relative movement between the threading dies and between the planishing dies to cause a blank to roll therebetween. 2. Inapparatus of the class described, and in combination, two complementary thread ing dies for threading a cap screw: blank and causing, during threading, the formation of a burr on the blank beyond the final turn of the thread, die carriers in which said dies are I 3. In apparatus of the class described, and

in combination, two complementary threading dies for threading a cap screw blank and causing, during threading, the formation of a burr on the blank beyond the final turn of the thread, die carriers in which said dies are mounted, two blocksalso mounted in said carriers and having a width substantially equal to the width of the threading dies, said blocks having formed thereon two complementary planishing platens for rolling down said burr and working the metal thereof into the shoulder of the blank to elongate it, and means for causing relative movement between said die carriers to cause a blank to roll between said dies;

4/ In apparatus of the class described, and

in combination, two complementary threading dies for threading a capscrew blank and V a cap screw with a ClllIGI'QIlt shoulder length,

o f -causing, during threading, the formation of "a burr on the blank beyond'thefinal turn of the thread, die carriers in which said dies are r I mounted, two complementary planishing platens for rolling downsaid burr and work-- ing the metal thereof intothe shoulder of 7 the blank to elongate it, separate die blocks I having a width substantially equal to the width of the threading dies and on which said platens are carried and which are also mounted in said carriers, and means for causing relative movement between said die carriers to cause theblank to roll between the I said dies. a

5. In combination, a die carrier comprising (a ledge, a threading' die blockmounted on tated to be assembled with said threading dies to form ledges for positioning blanks at predeterminedrelative positions with respect to'the threading dies.

In testimony whereof, I have hereunto set my hand. i I

GLENN H. WAYNE.

end of the first die block, the second die block I having a'planishing platen located substantially in the plane of the bottom of the die low the terminal line-of the die teeth. ,6. In"combinat1on,' means for threading and planishing a cap screw blank "compris- .fitheendsthere'of being chamfered, a second ing in part a block having 'a'series of teeth teeth of the first die, the platen extending be unthreaded block mounted on said first block. 7

and means for positioning said second block so that it forms a blank-positioning ledge with re'spect to one portion of said first block and "a 'planishing surface with respect to another portion thereof. I

7; In an apparatus for forming cap screws 7 having a threaded shank and an unthreaded shoulder, complementary'threading dies for 'forming'a thread on blanks rolled therebetween, and separate complementary blocks capacitated to be assembled with said thread- Z-ing dies to form blank-positioning ledges, said blocks, whenassemble'd, having plane surfaces betweentheledgesfand the threading dies lyingin aplane below the plane of. the bottom of the die teeth, whereby a p'ortion of the blank isleft free during rolling, f 50 said blocks being readily removable from the dies for substitution of interchangeable blocks of "different dimensions, whereby blanks may be positioned in different rela tive positions with respect to the threading dies.

8. In combination, oo-operating threading dies forv forming a thread onia blank rolledv 1 therebetween, and regulable means for providing blank-positioning ledges, associated with the threading dies, whereby blanks may be positioned at different relative positionswith respect tothe threading dies. 7

' 9. In combination, cQ-Operatmg threading dies for forming a thread ona blank rolled therebetween, and; regulable blocks capaci-

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