US1038482A - Pipe-threading die. - Google Patents

Description

B. BRDBN.

PIPE THRBADING DIE.

APPLICATION FILED MAR. 23, 1910,

LO88,482 Patented sept. 10,1912.

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f @5% a i l'rozu UNITED STATES PATENT OFFICE.

BRADFORD BORDEN,.0ZF TORONTO,` ONTARIO, CANAD, A SSIGNOR TO THE BORDEN COMPANY,. OF WARREN, OHIO, A CORPORATION OF- OHIO.

PIPE-THREADING DIE.

Speciv'cation 'of Letters Patent.

Pacenteasepa 10,1912.

Application. tiled March 23, 1910.V Serial No.- 551,188;

To all fwlwmz't may concern:

Be it known that I, BRADFoRuBoRDEN, of Toronto, in the Province of Ontario and Dominion of Ganada, have invented certain new and useful Improvements' in Pipe- Threading Dies; and I do hereby declare thefollowing to be a full, clear, and exact description 0f the invention, such as will enable otherss-k-illed in the art: to which it appertains to make anduse the same.

TheA primary object of this invention is to so arrange the cutting threads of threading dies-that engagement with a pipe or bolt nay be readily initiated and the cutting of a standard thread completed with the eX- penditure' of less energy than is ordinarily required: withhand-tools. To this end, I arrange the threads of: each die bit or segment, or thethreads of4 a Chaser, on two planes, the plane ofthe initially-acting or throat threads being. farther from the axis off' the toolfthan the plane of' the main cutting threads, which. latter threads are stepped up from the throat threads. The base line off theinitially-acting threads is preferably straight, that is, parallel `with theaxis of the die or tool, but it may, however, be s et on .aslight taper, that is, at an angle to the tool axis. The plane of the base-line off the main cutting threads is inset, relatively to the base-line of the throat threads, and-such main threads are preferably tapered, their plane beingalways nearer the axis ofthe tool-than the ini, tially-aeting teeth. By thus forming the die-segments or. chasers, the throat of the tool is enlarged and of substantially unlform diameter, and the throat threads will out partial threads or gutters, preferably o'n straight lines, and such throatl threads will, unaided by any leader-screw, or its equivalent, hold the tool. to` the. workI as against the resistance which occurs in stepping up to the maincutting threads. The lutter upon being brought into action, havingto cut to less depth, will.follow\ at correetiipitch and with lessenedA resistance in the partial threads or gutters formed 1n the work by the throat threads. With my invention Iv am enabled to obtain, with a solid or non-adjustable die stock, the same result as with an adjustable die-stock going twice over the work, with the dies or chasers set farther in for the second operatlon. By forming the step up between the throat threads: and the' main cutting threads, the .respective baselines being on different planes, If am enabled to set the 'throat threadsoutwardly. sufciently far to insure the die or tool readily taking hold of the work and hold the die or tool thereto when the main-.threads begin'to act. Without the step up fromone set of threads to the other the throatithreads would'have to be given a very abrupt taper whichwould be insutlicient, withoutthe aid of a leader-screw or its equivalent, to initiate engagement with the work.

In statingthat the root-s or base lines of the threads ofthe two series are on different planes, itis. understood that reference is made also tothe points of the threads; and although all the threadsvof each series. are shown as full threads with knife-like edges, itis to be understood that in some instances some ofthe points may be blunted.- In either event, however, the Abase lines and points of the threads Off the different series are on.. differentY planes, and the main threads are stepped up fromv the initially acting r threads. Y

The invent-ion will be hereinafter fully set. forth.A and particularly pointed out in the claims.'

In the accompanyingdrawings, Figure 1 is a faceview. and Fig. Qis a transverse sectional view ofasoliddie constructed in accordance with my invention. Fig. 3 is a view in perspectiveof` a-chaser or segment die. Fig. 4- 1s. aside elevation of a die' on an enlargedI scale. slight modifications. Fig. 7 shows a 'thread formed bythe soliddieof Figs. 1 and 2.

My present improvements are applicable to solid dies;. ad]ustable dies, and chasers capable. of automatically receding during the threading operation.

In Figs. l anda@ I havevshown a solid die having, as usual, a. central opening and a series of'inwardly-projecting threading bits. The .base of thethreads l. in the throats is outwardly set relatively to the base of the main cutting threads 2. In consequence, the 'diameter of the openin of the die is greatfest at, the throat, and" it is thus formed so ,that the initially-acting threads will remove comparatively little metal, and will form on the work but partial threads 0r gutters, being intended to cut inwardly but a third, or less, of the required depth. `The base-line Figs. 5 and 6 show the main cutting threads.

of these initially-acting threads is preferably straight, on a plane paralleling the axis of the die or tool. B forming the throat on' al substantially uni orm enlarged diameter so that the threads thereof will cut practically nothin more than gutters, (in depth but a small act-ion of that required for the completed thread) the die will start easily on its work. It is immaterial how many threads are in the throat, but for all practical purposes I have found that three or four are suiiicient, as even when on a taper they will all hold the pipe equally against the increased resistance offered by the main threads when the step-up is made thereto. y

' The base of the rnain cutting threads 2 is iii-set on a different plane from the base of the initially-acting threads, so: that the dieopening is, throughout the length of the main threads, of less diameter than at its throat. The base of the second series of threads is set on a taper,'and the base ofthe initially-acting threads may also be on-,aI taper (Fig. 5) but such latter taper must not, in order to obtain the advantages of my invention, be very abrupt. It 1s not necessary, however, that the second series be tapered, since, as shown in Fig. 6,- ,such threads may be straight and on a plane arallel with the rst-acting series. This 1s ldesirable for threading bo ts.

In'practice, starting the die or tool on the work is'comparatlvel-y easy on account 'of' the small amount of metal which the first series of threads are required to remove. The latter, although practically complete threads, form only gutters or partial threads in the pipe, being out-set to a degree which enables them to readily take hold of the work, The main cutting threads, when the step-up is made thereto, t'ravel in the gutters or partial threads on the pipe, and complete a standard tapler thread. The initiallyacting threads, in t e throat of the die, ordinaril make but one-third of a cut, or less, but t ey hold the tool to the work as against the increased resistance in stepping up to As the latter follow in the gutters .or partial grooves formed by the first series of threads, the standard thread ma be cut with less exertion than if all te Chaser-threads were cut on a continuous taper, and starting is far easier than if the first series of threads main threads.AV

In using an adjustable die-stock with dies having straight threads, to make starting easy the dies are irst'set to cut about onethird the required depth, and then after this operation is completed the dies are adjusted to standard. The stock will then start on the work with comparative ease on account of the partial vthreads previously formed. The result of the double operation of an adjustable die-stock is attained by forming the dies as hereinbefore described, the first series of threads effecting an easy starting, and forming partial threads or gutters in which the second series of threads follow to cut to standard taper.- I am thus enabled to obtain in one operation the same result as in two operations of, an adjustable die-stock.

Theadvantages of ymy invention will be apparent to those skilled inthe art. By so forming the threads of a pipe 'or bolt threading die that the plane of the baseline of the initially-acting threads is always outside the plane of the base-line of the finishing threads, whether the former threads are on straight lines or on a taper, I am enabled, to obtain an .easy-working die capable of readily initiating the threading operation and making the completion of the thread cutting comparatively easy.

I claim as `my l invention 1. A die formed with a cutting face having a series of threads in its throat, and a series of main cutting threads, the roots or base lines of the threads of the two series being on different planes, and the main threads step ed u from the throat threads.

2. Afdie orme with a cutting face having a series of threads in its throat Whose base line is on a plane substantially parallel with the axis of the die, and a series of main threads whose base line and points are on" with the axis of the die, and a series of main threads whose base line and points are at acute angles to the rst mentioned threads. In testimony whereof, I have signed this .specification in the presence of two subscribing witnesses.

BRADFORD BORDEN. Witnesses: i

FRANCES. MAGUIRE, J oHN A. MURPHY.

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