US77994A - William mantey - Google Patents

Description

@uitrit tntrs @sind @frn LettersPatent No. 77 ,994, dated llag/ 19, 1868.

l IMPROVEMNT IN TAPS FOR yGUT'IING SCREW-THREADS.

tlge tlgtmlt ttfttnr tu im tbm, Enters mettant mining pnt uf the. smut.

Be it knownthat I, WILLIAM MANTEY, of New Orleans, in the parish of Orleans, State of Louisiana, have invented anew Improvement in Screw-Cutting Tap; and hereby declare that thefollowing is a full and exact description thereof, reference being had tothe accompanying drawings, and to the letters o'fireference marked thereon, said drawings making part of this specification, in which- Figure A is `aV longitudinal elevation,

Figure B a transverse section of a 6, and

Figure C a regular delineation of the three cutting-sides.

Figs. A and B are natural size; the iig. C is double the size. v

My tap is out or chased and grooved in the ordinary way, but I take, commencing on thc point, e'very other thread almost out, so that it is prevented from acting, and gives ample room for the cuttings, thereby lessening friction one-half. The last four round gangs ofthe thread I leave sharp, and give the nut to be cut a Vperfect: finish, as will be seen in fig. A. Fig. 0,*the delineation shows that the threads Nos.` 1,3, 5, 7, nre

prevented from action, having been led out, while the three-ds Nos. 2, 4, 6, 8, will cut the screw with ease.

I do not claim the groove or number of grooves, nor the taper of the tap or screw, but

What I claim as my invention, and desire to secure by Letters Patent, is. p i

In the construction of taps for tapping nuts and the likefobliterating or diminishing every alternate cuttingthread, from the point of the tap back to near the'termination of the cut pol-tion, but leaving, in a space near said terminal portiorn'all the cutting-'threads full and perfect, as herein described'and shown. i

New Orleans, January 21, 1868. v WILLIAM MANTEY.

Witnesses:

JN0. F. BRAUN, M. SAvoLIs.

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