US75182A - of west chbshike - Google Patents

Description

PATENTED MAR 'f3 |868 JOHN MIX, OF WEST CHESHIRE, CONNECTICUT.

Letters Patent No. 75,182, dated rlfarch 3, 1868.

IMPROVEMENT IN MANUFACTURING GIMLETS.

dlp .sagome referat tu in tigen trtters @anni mit uniting gaat nt tige stmt.

TG ALL WHOM IT MAY CONCERN:

Be it known that I, JOHN MIX, of West Cheshire, in the county of .New Haven, and State of Connecticut, have invented a new and useful Improvement in the Manufacture oi' Gimlets and GimletBits, of which the following `is a full, clear, and exact description, reference being had to the accompanying drawing, forming part of this specification, and in which- Figures 1 and 2 represent face views of lower dies used in my improved mode of manufacturing gimlets or 'gimlet-bits, and

Figures 3 and 4 transverse sections of the same, with work or stock arranged" therein; iig. 4 also showing the application of an upper die in connection with the lower one, with the work arranged in between them; iig. 3 being taken as indicated by the line x in fig.' 1, and iig. 4 taken as denoted by the line e e in iig. 2.'

Figures 5, 6, T, 8, and 9 illustrate longitudinal views of gimlets or gimlet-bits in various stages of their manufacture, and under different forms of construction.

Similar letters of reference indicate corresponding parts. Y

In the ordinary process of making gimlets or gimletbits having more or less twist, it is usual 'to swage the cutting-portion ofthe gimlet or bit, including the twist, from a blank having a'lattened form on its one side or face, and rounded form on its opposite side, in a straight line or direction with the shank of the gimlet or bit. Under such process or mode, however, of making such articles, the after-operation of wringing the blank to form the twist necessarily involves, from the shape given the blank or stock, a regular tapering character to the latter, from the roet of the attened portion to the point, which is objectionable, as causing the greatest swell too far from the point, and into, for instance, the pod of the gimlet or bit, which after-part should -formed of a taper or diminishing diameter in a backward direction, for the purpose of establishing clearance of the cuttings in contradistinction to cutting. This desideratum my invention accomplishes by giving-t0 the. I forward part of the llattened portion of the blank orstock of which it is desired totorm the twist, a onesided or bent lateral direction tothe axis of the stock, and afterwards rolling over said bent portion toiform the cutting-twist, which gives the largest swell at the root of the latter, and establishes a cleaner, and, it may be described as abrupt, finishing-cut at such point', leaving the balance of the ilattened portion, whether grooved, twisted, or plain, of a regular diminishing taper from the root of the cutting-twist. 1.

Referring to the accompanying drawing, I take a piece ofround-bar steel, of the required length for the gimlet or bit, and slightly bending and pointing it, insert it, lwhile heated, in a lower die, A, g. 1, and, bringing' down a; suitable upper die'or punch, give to the stock B a attened form on its one side or face for a portion of its length from the point, as, for instance, represented in fig. 5, where it is shown as ilattened from the -poinft' a as far up as b, the same beingof a round conliguration on its opposite side; and,.through the shape ofthe dies, I further give a lateral direction or bend to the more forward part of such flattened portion, as from a to c; Where it is desired to form the after-part ofthe flattened portion, as from c to b, of a grooved or pod-like form, d, figs, 6, 8, and 4, then the upper die or punch, C, and lower die, A', are constructed t9 thus formsueh part, as shown in iig. 4, but the after-part of the flattened portion may, if desired, be left `plain or level, as at e, in figs; 5 and 7. Whatever the configuration,l however, given to the after flattened portion ofthe stock, the front bent forwardpart of the latter, as from a to c, ligs. 5 and 6, is rolled over, by, say, means of tongues', or otherwise, to forni a cutting-twist,f, gs. 7, 8, and 9, from thc parte as a base, where the flattened portion is widest. i This brings the point a of the stock out of itslateral position into the axial line of the latter, and gives the largest swell or biggest diameter at the root of the cutting-twist, with a gradually-diminishing taper backwards from that point for the remainder of the ilattened portion, which construction is in no way analogous to wringing the stock with the whole otl the flattened portion in the saine straight line as the remainder of it, and which ordinary construction gives the biggest swell in the roar of the cutting-twistf, that, to establish an easy and clear cut, should have immediate relief, and the after-portion be free to enter theV cavity made by the cutting-l twist, with roomy escape for the cuttings, but in no other way aiding or forming the cut, or binding on the hele made on the projection or insertion of the cutting-twist through the latter.

Fig. 7 represents a giml'et or ginilet-bit constructed as from the blank shown in iig. 5, with the after flattened portion c, from c to b in fig. 5, left plain or straight; fie. 9, a gimlet or. bit constructed from the same blank, but with the after lnttened portion twisted inl the ordinary way, by wringing the stock, as at g, after the cutting-twistf has been formed by rolling over the bent portion of the blank; and fig. 8 shows o gimlet or bit formed from the blank represented in fig. 6, with n pod-like configuration, d, given it in renr of the cutting-twist. Thus the gmlet or gimlet-bit, made according to this, my improved mode or process of manufacture, may either be part twist and nt, 'part twist and pod-form, or Wholly twist.

The usual finishing and polishing of the gimlet or bit, and cutting of a. screw-thread on its forward end or point, may be subsequently done in the ordinary manner.

What is here claimed, and desired to be secured by Letters Patent, is

The method herein described of forming blanks for gimlets or gimlet-bits.

JOHN MIX.

Witnesses:

J'. W. CooMBs, A.- LE CLERC.

Images