US2638818A - Wire finishing method and apparatus - Google Patents

Description

y 19, 1953 G. J. STEVENS 2,638,818

WIRE FINISHING METHOD AND APPARATUS I Filed July 25, 1949 2 Sheets-Sheet 1 INVENTOR. GEORGE \JCHN STEVENS mpg 7 llE HE ms ATTORNEY y 19, 1953 G. J. STEVENS 2,638,818

7 WIRE FINISHING METHOD AND APPARATUS Filed July 25. 1949 2 Sheets-Sheet 2 GEORGE QOHN STEVENS I N VEN TOR" HIS ATTORNEY Patented May 19, 1953 UNITED STATES PATENT OFFICE wms Fmis us' APPARATUS George John Stevens, Baltimore, assignor to Armco Steel Corporation, a corporation of Ohio Ap etite-lichen, 1949; seen No. 106,705 6 claims. (Cl. sin-22) My invention relates to the finish treatment of metal bar, rod and wire stock, and more particularly concerns the art of mechanically imparting a satisfactory finish to Wire stock formed of stainless steel and generally similar metals: displaying a high degree of hardness.

An object of my invention, therefore, is to provi'de a method of nicely finishing, metal bar, rod and wire stock, requiring but a minimum number of procedural and manipulative steps, each simple and rapid in itself and requiring only in-. expensive apparatus, which method is characterized by its basic simplicity and rapidity of operation, the low cost attendant upon the piac' tice thereof, and the absence of necessity for highly skilled operators and attendants in the performance of the method.

Another object is to provide apparatusfor coldworking and finishing hard metal bar, we and wire stock which will impart high finish detail to the metal stock with nicely calibrated finished gauge and at uniform finishing pressures, which demands but a small number of mechanical and structural elements, and these simple, rugged and inexpensive in themselves, which displays Another object is to provide an apparatus of the general type described wherein all tendency towards chattering of the mechanical parts is eii'ectively suppressed or avoided and unusual shocks are absorbed, wherein heat generation is held at a minimum, and wherein galling of the metal stock due to excessive friction and tendency of the wire to weld momentarily to the cut ting edge employed, as well as any tendency of clogging the cutting edge, are effectively avoided; and which apparatus is characterized by the sub; stantial absence of scarring, gouging or tearing of the suriace of the wire.

All these, as well as many other highly, advan tageous objects and advantages attendant upon the practice of my invention will in part be obvious and in art more fully pointed out hereinafter, during the course of the following specification. i

My invention accordingly resides in the several parts, elements and features of construction;

and in the method and procedural and manipu lative steps employed as well as in the combination of each of the same with one or more of Figure 2 Figure 1;

Figure 3 is an elevation of a portion of cutting assembly of the apparatus; while Figure 4 discloses, in elevation, a modified form of the cutting and scraping blade employed in the apparatus of my invention.

Throughout the several views of the drawings like reference characters denote like parts;

To facilitate a more ready understandingof my invention, it may be noted at this point that the art is confronted by the need for imparting a surface finish of high quality to stainless steel in the form of bar, rod and wire stock. In many applications of stainless steel Wire for example, eye appeal is a particularly important element suchas in the production of refrigerator trays, grills for handling food; and the like. These items have the feature in common that the consumer pays a premium lprice therefor in order to obtain adevice of pleasing appearance, and as insurance against rusting or unsightly corrosion; traceable to microscopic scams or pits wherein food particles or acid might lodge and is an end view of the apparatus of initiate corrosive etching. Many such articles" blemishes occasioninstant rejection.

Because of th importance of surface perfection in fabricated products there is required stainless steel bar, rod and wire stock which is substantially free of those def'ects which areso common to ordinary metal production, and which include, illustratively, seams, minute sliverapits, laps, imbedded scale and similar imperfections. The presence of these defects has long posed a problem and particularly so in those instances where successive passes are had through dies in acold drawing process, wherein no intermediate treatments are employed to smooth the wire or obliterate faults. They are encountered in. everyday fnill practice, and result from myriad causes during hot-rolling particularly, and-as well, from mechanical blows during transportation about the mill and in other processing. Added up, the

accumulative effect of this faulting is to render the finished product less, attractive than is desirabl for the competitive purposes for which it Will b e l'fiplbyd.

Frequently, the surface defect is so serious as to necessitate discarding the product. Often, instead of nietal' displaying a highly polished, lust'rous and pleasing appearance which readily lends itself to ele'c'tropqlishing subsequent to fab ic'ation into" a mirror finish, there is pros'u' sda surface which isst'realed, frosty, and

dull. Notonly is the production of such surface costly, in that special after-treatment is required, such for example as mechanical buffing, but indeed, in the production of certain fabricated articles, involving imparting an intricate shape to the wire, this after-treatment is impractical, and it is impossible to impart the required good appearance to the fabricated wire.

Now in the prior art considerable difficulty has been encountered in imparting a high quality finish to stainless steel bar, rod and wire stock. Although numerous methods are available, none quite meets the problem of simplicity, efficiency and cheapness required. To illustrate, centerless grinding gives a good surface but this method can be resorted to only in the most specialized instances, because of the cost attendant upon straightening the rods or wire before insertion in the grinding machine. Alternatively, resort must be had to special devices in order to grind the coiled wire. And too, the element of costs attendant upon this grinding technique effectively excludes it from ordinary use. Moreover, aside from the element of cost, centerless rinding is so slow and tedious as to preclude its use where high speed is essential.

Similarly, the use of rotating cutting tools is impractical, expensive and time-consuming.

In the production of copper wire there has been employed the technique of scraping or shaving the metal wire, following drawing to approximate size with a slight degree of oversize. This is used as one of the final steps for preparing the wire stock for the application of insulation or coatings, as Well as for other special purposes. I find, however, that such processes, while entirely satisfactory for the treatment of soft metal stock of which copper wire is typical, are not entirely satisfactory for the treatment of stainless steel bar, rod and wire stock.

Many reasons contribute to this situation. Illustratively, the forces required to pull refractory metal wire stock through the die are considerable, so that it is highly important and essential that careful alignment of the metal stock relative to the die be achieved. Failin this, chattering of the die is encountered, and gouging of the wire stock is occasioned. Such treatment is attended by the evolution of a high degree of heat. Moreover, a strong tendency is observed of the stainless steel metal wire stock to gall, i. e., become injured as a result of excessive friction; and as well, it is found that the metal stock will momentarily Weld to the cutting edge of the die. This not only spoils the finish of the wire, but effectively avoids the very purpose of the treatment.

Of the various methods tried I find that certain inherent and basic advantages attend upon shaving a very thin layer from the surface of the wire as a final phase in the manufacture thereof. The wire, of course, is left slightly oversize as it is introduced into this step in order to adapt the wire to the shaving technique. The problem still remained as to how to accomplish the foregoing, and this at high speed, without adding excessive costs or extra operations to the production operation. This problem has not been adequately solved prior to my invention.

An important object of my invention, therefore, is to provide a method and means for mechanically treating stainless steel bar, rod and wire stock and generally similar metal stock in a cold-drawing process so as to effectively eliminate the defects attendant upon the occurrence of seams, minute slivers, pits, laps, imbedde-d scale and similar surface defects and imperfections, and this in rapid and inexpensive manner, Without the necessity of straightenin the wire prior to or following passage through the treating apparatus; which method is readily applicable, in the substantial absence of skilled operators, for the treatment of metal stock of both small and large size regardless of the cross sectional configuration thereof; and which will permit the production of a uniformly polished, lustrous surface to which a mirror finish can be readily imparted in the substantial absence of streaked, frosted or dulled portions, which surface effectively precludes the occurrence of rust or unsightly corrosion and effectively avoids the occurrence of microscopic points of attack.

Viewed from its simplest aspect, my invention may be considered as comprising the provision of two or more bladed cutting tools, complemental to each other, disposed in generally opposed relationship, and each being held under a condition of strain by springs or other flexible means. This is desirable so that when the cutting elements encounter undue local and momentary increase in pressure of the metal stock on the cutting edges, they will yield momentarily so that the pressure is automatically relieved. In other words, the spring-imparted force is overcome by the momentarily greater and opposed force imparted by the metal wire. By this means, I effectively avoid the hazard of burning the wire stock as a result of acute momentary friction. At the same time I achieve the happy result of avoiding premature dulling of the cutting surfaces which would otherwise attend, in all probability, upon the cutting die being forced to bite into the metal stock. Moreover, I effectively remove the danger of the freshly-cut metal welding to the cutting tool; and as well, I avoid the creation of a built-up edge on the cutting tool, resulting from build-up of wire metal welded thereon, and which, once formed, displays a detrimental tendency to scar, gall, or mar the shaved wire. Additionally, I eliminate danger of clogging the cutter elements by entrapped chips, and as well, avoid the progressive gumming of the metal as is so commonly attendant upon the treatment of high alloy steels.

And preferably I impart a negative rake to the cutting tool, which I frequently refer to herein as a die. This negative rake provides a scraping action rather than a conventional cutting action; and in my preferred embodiment I elect to use a scraping tool. However, I do not desire to be limited to this cutting technique, but contemplate and seek to encompass by this application both a scraping action, as a preferred embodiment, and a true cutting action, as within the scope of my invention. To this end, I employ the term cutting, as used in connection with the cutting or scraping action of the cutting or scraping tools, in its generic sense, rather than in a more limited sense, except when such definition is clearly inconsistent with the scope and intent of the text hereof.

With the foregoing general disclosure in mind, description will now be made of a specific embodiment of my invention according to Figures 1 and 2, which is particularly adapted for shaving wire of circular cross section. I provide a base plate In of heavy metal, preferably of generally circular form, and which is drilled as at IDA, IDA to permit its being bolted to a standard wire-drawing bench. Inasmuch as these wire-drawing benches are conventional in the art, and assume many embodiments, and

since the particular shape and construction of bench does not in itself form part of my invention, disclosure thereof is omitted in the drawings, for simplicity and clarity. And on said base plate I provide a series of two or more assemblies for holding cutting tools. Conveniently, these may be four, five, or more in hum her. In the present embodiment, however, I em ploy a series of three such assemblies; Accord: ingly, the three such assemblies, indicated generally at II, I2 and I3, are provided for holding suitable scraping tools thereon as an essential part thereof.

Considering now, by Way of illustration, the assembly II, this consists of paired metal sum ports HA, HA disposed preferably diametrically opposed to each" other, and suitably bolted to the base plate It so as to allow a slight play therebetween. Here, by Way of illustration, a portion of the supports I IA, HA, of reduced section- (not shown), passes through the base plate It and terminates in threaded shank IIB, II-"Ba Nuts NC, NC serve, together with the related shank portions I I3, HR, to make the respective sup ports I IA, I IA, loosely secure to the base plate I0.

At the free ends of the supports HA, HA, I provide extension members IID, II-D, formed of suitable metal, of section sufiicient to impart sub-- stantial rigidity to the assembly. These extensions are disposed at right angles to the length of the support. That is, they extend substantially parallel to the plane of the base plate It, on an imaginary diameter thereof, and are disposed to wards, but terminate short of each other. Thus, these extensions, while pointed towards each other, do not meet, and leave a spaceslirrouriding an imaginary line projected axially through the center of the base plate and through the'center of the supports. This effectively places the axis ofthe extensions above the center of the base plate.

These extensions may be made fast in any suitable manner to the supports HA, HA. the preferred embodiment, the extensions IIB; HB are each provided with a transverse bore, and headed bolts HE, HE pass through said bores in extensions IID, ND and thread into tapped recesses (not shown) disposed centrally and axially in the free ends of supports HA, HA. Suitable lock washers HF, HF arexdisposed about the shafts of the bolts IIE HE and are interposed between the outermost surface of the extensions I ID, I ID (remote from the base plate Ill) and the headed ends HE, HE of the bolts. Preferably, although not necessarily, these may be split lock washers. Y

On the faces HG, HG of the extensions IID, IID, facing the base plate I0; I provide recesses or inset portions I III; I I H. As Will be seen, these recesses I IE, I IH are slightly bevelled, and taper to a slight angular extent outwardly from the base plate in a direction towards the axisof the wire-supplying orifice IUB provided centrally of the base plate IE]. Moreover, the bevelled recess NE on the one extension IID'preferably is'advanced slightly beyondthe bevelled recess onthe other extension. And in'the region of the recesses IIH, III-I the extensions IID are drilled as at IIJ, IIJ to receive hold-down means such as headed bolts I IK, I IK for the corresponding element IIL, HL of the cutting tool. These latter elements, by reason of the advance or one bevelled recess beyond the other, are in a somewhat staggered position.

This bevel imparted to the recesses III-I, III-I serves to impart a negative raketo the. cutting tool IIL, so that the latter, in use, will give rise to a true scraping, as distinguished tram a cuttingl action. Conveniently, the cutting edge HM, NM or the cuttingtool IIL, L is ground at an approximately 90 angle. This is not mandatory, however, and the angle of cut as just recited may be departed from to a reasonable extent'vvithout seriously detrimental effect. The cutting blades or die elements II'L, IIL are termed or highly resistant tool fne'tal, ans 1-1-1115 tr'atively, are sufiiciently thin to permit flexing where excessive loading is encountered.

perhaps best seen in Figure I, the center I'I'N, IIN or each cutting edge is ground to the shape of a semi circl'e, so as to conform closely to and adapt itself to the shape of the wire just being shaved. It may be noted here that the semi eircular recesses IIN, IIN in thecutting dies are provided only where metal stock of circular section is undergoing processing. It is eq'i'ially feasible, and is within the fullcontemplation of my invention, as pointed out hereinbefore, to conf'orm the recesses IIN, IIN to the shape of the section of the particular metalstock which isnndergoing" treatment. Thus my invention readily lends itself to the treatment of stock of various configurations; and to accommodate the shaving apparatus to different shapes of bar, rod and wire, it is sufficient simply to back oil? the hold-down bolts I'IK, I IK from their recesses IIJ, IIJ in the extensions IID, IID, and replace the shaving dies, the reverse of the foregoing procedure being employed in order to bring the replacement dies in working position.

So mounted, the paired tools or cutting dies nnunare disposed on' the extension arms in such fixed position that the opposed semi-circular openings IIN, HN therein nearly meet, and together form a generally circular cutting openihg divided in two, with one semi-circular opening being staggered with respect to the other a smalr amount, say about f'. As has been stated, this opening IIP thus formed preferably should be disposed nearly opposite the center of the base plate It. Preferably I dispose this opening I IP exactly opposite the corresponding opening HEB in the base plate I6, through which. openmg I eBthe metal stock is supplied.

While I have referred hereinbefore from time to ti'nie to cutting tools and to cutting opera- I tion; I used this term inits generic sense to encompass both a true cutting action and a true shaving action, all as more fully explainedhereinbefore'. To this end I employ a tool mounted so as to impart a negative rake thereto, also as explained'here'inbefore. In practice, I prefer to rely u'pon a shaving, as distinguished from a cutting action; itbeing my observation that superior results are achieved. thereby. However, satisfactory results generally attend upon the use of a tool having a positive fake and thus giving rise to a true cutting action;

The spring action of the cutting die elements I IL, I IL ordinarily is sufficient to assure adequate force being applied against the metal stock to give proper shaving. This forces the dies IIL, IIL against the metal stock in a direction towards the center line ofthe cutting aperture, so that they are applied thereagainst with calibrated nicety. The degree of tension to be eniployed is best dictated by experience, knowledge as to the composition ofmetal undergoing shaving, the quantity of metal to be removed in a pass through a single set of dies, together with generally similar factors. I find it unnecessary to provide for any substantialdegree of move ment, my observation disclosing that a very slight relaxation of movement of the die from time to time, this on the order of one thousandth of an inch, will assure a continuous flow of fine chips, preclude built-up pressures, and permit the die to yield slightly upon encountering local thick spots in the metal stock. As soon as the local reverse strains are eliminated, the spring force of the die elements IIL, IIL assures the cutting surfaces being applied against the stock with undiminished pressure.

It will readily be appreciated from the foregoing that important forces will be encountered, tending to force apart the cutting tools IIL, IIL and as Well, tending to force the extensions I ID, IID outwardly at an obtuse angle relative to the supports IIA, IIA. To resist this tendency, I provide studs IIR, IIR disposed one on each side-face of each extension arm IID, IID. Thus, there will be two such studs IIR, HR for each extension arm. The studs IIR. on the rightmost extension arm IID in Figures 1, 2 and 3 each has threaded therein a threaded bolt I IS, which extends generally parallel with respect to the extension arms and towards the other support IIA. These .bolts extend loosely through suitable openings in the studs IIR, II R of the leftmost extension I ID and protrude therebeyond. A loclzdown nut II T, IIT is provided, one on each bolt IIS, on the free end thereof.

By threading down this take-up nut UT on. its corresponding bolt IIS until it abuts against the outer face of the corresponding stud I IR (the face thereof which is remote from the corresponding stud IIR of the other extension IID) I am enabled to lock the two extensions rigidly with respect to each other in that position in which they are most nearly brought into exact alignment. Substantially all tendency of the assembly towards detrimental chattering and vibration due to variation in resistance interposed by the cutting dies to the passage of the wire stock therethrough is effectively suppressed. And, of particular importance, I find that these bolts provide additional elasticity for the shaving die elements IIL, IIL.

The intermediate die assembly indicated generally at I2 and having support arms IZA, IZA and extension arms I2D, I2D is substantially identical with the first-mentioned assembly, indicated generally at II, with two important differences. Firstly, the supports IZA, I2A, of equal length, are appreciably shorter than the supports IIA, IIA. Preferably, although not necessarily, these supports I2A are two-thirds the length of the supports NA. This is primarily for the purpose of symmetry and to permit equalizing to a substantial extent the stresses through the wire stock. It is entirely possible, however, without departing from the spirit of my invention, to form the supports I2A, I2A

of any desired length. Secondly, the supports I2A, I2A are offset angularly on the base plate II, relative to the supports IIA, IIA. In this manner the cutting tools I'ZL, I2L of the assembly are disposed in such manner that the transverse opening I2P between the split die elements is angularly offset with respect to that opening IIP through the cutting elements IIN, IIN for reasons which will be developed hereinafter. Again, preferably but not necessarily I offset the supports I2A, I2A 120 relative to the supports IIA, IIA. Finally, I provide a third such cutting assembly indicated generally at I3, I3 which is in exact conformity with the assemblies II and I2 except in the two re'spectsthat the support arms ISA, I3A thereof are of lengths different from both supports IIA, IIA and IZA, IZA. Preferably, although not necessarily, these supports ISA, ISA are one-third the length of the supports IIA, IIA and one-half the lengths of the supports I2A, I2A. Secondly, the supports ISA, IEA are angularly ofi-set on the base plate I0 24:0 with respect to the supports IIA, I IA and 12 relative to the supports I2A, I2A. In this manner the split opening between the adjacent cutting tools I3L, I3L is offset angularly with respect to the opening through the cutting dies IIL, IIL and IZL, IZL.

With the foregoing construction in mind, it will readily be seen that with my new cutting device properly disposed on the wire-drawing bench, the wire to be processed is passed, first through the guide aperture IIIB on the base plate I0, then through the opening [3P of the nearest cutting tool, then through the opening II]? of the last cutting edge. As a result of disposing the paired cutting elements IIL, IIL and so on in angular arrangement relative to the periphery of the base plate, those sections of the wire which are not shaved clean in the passage through one such cutting assembly, as for example at the open seam between the elements of the split die, are scraped clean in the passage through the next successive cutter.

As I have stated, I find the standard wiredrawing bench to be an entirely satisfactory means for moving the wire through the apparatus. I find it entirely feasible to combine my scraping or shaving operation with the final pass of the wire stock through a conventional colddrawing operation. When this technique is resorted to, it is apparent that much manipulation is eliminated, which would be requisite were not the two steps combined into a single procedural phase; Moreover, the added advantage attends upon such practice in that the scraping serves here to remove the products of cold-drawing such as excess lea-d, lime, or other drawing lubricants.

As illustrative of the operation of my invention, I have employed a coil of type 302 (18-8 chromium-nickel) stainless steel wire of circular cross section. I shaved the same to a depth of about 0.0005 to 0.002 inch, employing my new shaving apparatus. tion of three paired cutting dies, using a conventi'onal drawing bench as a source of power. I fed the wire first through a conventional col-ddrawing die, and there reduced the same to a cross sectional diameter slightly in excess of the desired finish size which was 0.25 inch in diameter. As the wire moved from the cold-drawing die, I fed the same to the guide opening IHB of my shaving apparatus, and thence through the three shaving dies, finally winding the same around the winding drum on the drawing bench. In the operation described, I employed a drawing speed of fifty feet per minute. However, it is entirely feasible to increase this speed to as much as one hundred feet per minute or more. The average depth of metal removed was about 0.0005 inch.

Upon inspection, it was found that as the wire emerged from my new shaving apparatus, it was uniformly smooth and free of imperfections and as a result, presented a clean, fresh, metallic appearance which was substantially free of seams, slivers, pits, die scratches, or chatter marks. I thereupon cleaned the finished wire of grease and residual drawing compounds by flash-pickling,

In so doing, I employed a combina and transitory excess pressure conditions.

and then electro-polished the wire stock in glycolic-sulphuric acid solution.

Inspection disclosed the electro-polished surface to be uniformly mirror-like and highly burnished, and in this respect, in sharp contrast with similar wire, cold-drawn at the same time through the same die but not shaved, and which wire stock, so treated, displayed a much duller finish following electro-polishing and one less uniform in quality.

While in the apparatus illustratively described suffici-ent elasticity is had in the die elements and in the ten'sioning bolts to assure the desired shaving of the metal stock, it will be understood that where desired, individual springs may be provided for the die element and provision made for adjusting the degree of tension with which the spring elements apply the shaving tools I IL, IIL against the stock. Such an embodiment of my invention is shown in Figure 4 of the drawing. There it will be seen the stiif springs I IV, IIV replace the mid-portions of the bolts IIS, I IS.

I have found that by imparting flexibility to the cutting tool important advantages are achieved in addition to simply relieving localized lustratively, I effectively eliminate the danger of chattering, and as well, avoid the chatter marks which so commonly attend upon the use of solid or rigidly fixed cutter elements. Moreover, all necessity of straightening or positioning the wire before cutting is removed. Coiled wire may be shaved without necessity of recourse to positioning dies inserted before and after the cutting tool. The flexible and movable character of the cutting edge enables it to follow the wire in its convolutions, bends, or twists, within reasonable limits.

My invention permits the ready shaving of bar, rod or wire stock of any regular cross sec tion, be the same square, hexagonal, poly-faced or of special section. The grinding and conditioning of the two cutting edges to accommodate conventional round or even unconventional shapes, is readily accomplished in essentially the same manner that ordinary form tools are conditioned. The dies may be readily replaced to accommodate for wire stock of different sizes and cross sections. The ordinary draw bench can be readily employed without material adaptation. The shaving apparatus is simple and of low first cost. It can be operated in the absence of skilled labor. It is adapted to high operational speeds. It gives rise to a wire product of superior finish, permitting electro-polishing with entirely favorable results. All these and many other highly practical advantages attend upon the practice of my invention.

The foregoing disclosure is merely illustrative, and it will readily be appreciated that not only will many modifications of the present embodiment suggest themselves to those skilled in the art, but that as well, many embodiments of the basic underlying inventive thought will likewise present themselves. Accordingly, I desire that the foregoing description be considered solely as illustrative, and not by way of limitation.

Iclaim:

1. The method of shaving metal stock, comprising, in combination, mechanically shaving the stock in a series of stages spaced-from each other axially along the stock and at differing angles about the axis, each stage accomplishing a slight reduction of the diameter of the metal stock.

2. The method of shaving stainless steel wire stock, comprising, in combination, mechanically shaving the wire at negative rake of the shaving tool in a series of stages spaced from each other and at differing angles about the axis of the wire, and resiliently applying the shaving edge of each shaving tool to the stock during the shaving operation to permit the relief of excessive pressures.

3. Apparatus for mechanically finishing metal wire stock, comprising, in combination, a base plate having an orifice through which th metal wire stock is supplied, and a series of transversely split cutting dies, each having a central orifice therethrough disposed in spaced relation both with respect to each other and to the base plate, the openings in said dies being disposed in approximately the axial prolongation of the opening in the base plate for the passage of said wire stock in cutting relation to said dies.

1. Apparatus for mechanically finishing metal wire stock, comprising, in combination, a centrally-orificed base plate through which orifice the metal wire stock is supplied, and a series of transversely and diametrically split, centrally- 1 orificed cutting dies carried by and disposed in spaced relation both to said base plate and to each other, with their orifices in the axial prolongation through said base plate-orifice, the diametrically-disposed transverse split of each set of dies being angularly offset with respect to the split in the other set of dies,

5. Apparatus for mechanically finishing metal wire stock, comprising, in combination, a support, a base plate on said support and having an orifice therein through which the metal wire stock is supplied, and a series of cutter assemblies, each having a central orifice therethrough, also mounted on said support and disposed in spaced relation both with respect to each other and to the base plate, a negative rake being imparted to the cutting edges of said outter assemblies, the orifices in said cutter assemblies being disposed in aproximately the axial prolongation of the orifice in the base plate for the passage of said wire stock in operable relation to said cutter assemblies.

6. Apparatus for finishing metal stock, comprising, in combination, a base plate; a plurality of pairs of supports fast on and extending outwardly therefrom perpendicularly to the arm thereof, the length of each pair of supports being different from that of the other pairs; extension arms of each pair extending towards but terminating short of each other; means on each pair of extension arms for imparting yieldingly urging the two together; and split cutting dies disposed, one element on each arm of each pair of extension arms, the metal stock being drawn through said base plate and through said cutting die assemblies.

GEORGE JOHN STEVENS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 166,337 Brown Aug. 3, 1875 1,790,731 Thacher Feb. 3, 1931 2,030,562 Barnes Feb. 11, 1936 2,233,928 Weaver Mar. 4, 1941 2,300,967 Reed et al Nov. 3, 1942 2,530,219 Bartusek Nov. 14,, 1950 FOREIGN PATENTS Number Country Date 166,403 Germany Dec. 28, 1905

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