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Publication numberUS2328629 A
Publication typeGrant
Publication dateSep 7, 1943
Filing dateJan 4, 1941
Priority dateJul 29, 1940
Publication numberUS 2328629 A, US 2328629A, US-A-2328629, US2328629 A, US2328629A
InventorsEich Frank A, Higgins Frank E
Original AssigneeUnited Shoe Machinery Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
US 2328629 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

Patentecl Sept. 7, 1943 Fra nk A. Eich, Melrose, Mass., am! Frank E. Higg1ns, 1'laistow, N. H. assignors to United Shoe Machmery Corporation, Flemington, N. J., a corpora.tion of New Jersey Original application July 29, 1940, Seria1 N0.

- 348,090. Divided und this 4, 1941, Seria.l N0. 373,156


Heretofore, it has been diflicult rapidly and easily to drill hard wood, such as maple. with a twist drill of the usual type because the dril1 would not readily penetrate the work but would become overheated, which would draw its temper, and burn the wood. Accordingly, it has been necessary to use for th is work a drill which has a sharp pyramidal center point and small circumferential lips which cut and define the outer Wall 01' the bottom of the drilled hole before the chips are shaved of1 and removed from that part of the hole by the body of the drill. While such drills are suitable for this work, they must be kept sharp by frequent and difficulthand grinding in order to maintain them in proper working condition.

It is an object of the present invention 120 provide a multi-fluted, and preferably a, doublefiuted, twist dri1l with a point somewhat similar to the usual form of twist drill point but which is especially shaped to penetrate hard wood without exoessive heating. Such a drill may be sharpened conveniently and accurately on a grinding machine which has been specially developed for the purp0se by the present inventors, which machine is described and claimed in an application for Letters Patent of the United States, Seria1 N0. 348,090, filed July 29, 1940, of which application the present application is a division.

The various features of the dril1 consist of end surfaces cf novel shape arranged to meet in a nove1 manner to form cutting edges and cleararmes suitable for the intended c1ass of work.

One of these features eliminates the usual chisel edge tha'b is regularly formal across the web of a dril1 at 90 to its axis. 'Ihis is especially important as such an edge impedes the penetration Of the dri1l and sorapes er tears the fibres of the wood in the center of the hole being drilled. For such an edge, there is substituted one which is in two portions, each of which makes an angle of 1ess than 90 to the axis of the drill, and together provide an edged web which is inclined to the surface being drilled and easily penetrates the work. v

The end of the dri11 is diametrically symmetrical and consists of four irregularly shapeddiscontinuous faces meeting in a common point a.t substantially the geometric center of the drill.

Referring to the drawing,

.Fig. 1 is an enlarged erid view of the drill of the present invention;

Fig. 2 is an enlarged e1evation of the dr111 100king in the direction of the arrow A in Fig. 1; a.nd

application January Fig. 3 is an enlarged view 0fthe drill, looking in the directlon cf the arrow Bin F1g. 1.

As illustrated, the preferred form of drill o! the present invention is a right-hand, doublefiuted twist dri1l M so that. when operating to.

dri1l a hole, it rotates in the direction of the arrow in Fig. 1. It is provided with a nove1 end which makes it possible to drill hard wand et high .speed without drawing the temper of the drill or burning the wood. In Fig. 1 the fiutes for slight clearance) in the surface of a cone 013 approximately included angle (see Flg. 3) and the wider concave clearance surfaces 20 and 20'. The surfaces 20 and 20' are locatad behind the1r respective lands and extend to substantially the geometric center of the drill, cutting into the web of the drill. Each 1and and the concave clearance surface in front of lt meet to form a cutting ede on the web at one side of the center of the dri1l (i. e., I8' meeting with 20 and 18 with 20'), as indicated at 22 and 22' on what will be termed the forward edf;e of each 1and. The two parts of the cutting edg'e thus formed appear, in end view, to extend across the web of the drill in substantially -a straight line.

The remaining portion of each cutting edge as indicated at 24 and 24', continues in a. curve a1: a. considerable angle to the Just-described portions 22 and 22', until it ends at the circumference of the drill. 'I'hls part of each edge is formed by the meeting of the remalning portion of the forward edge of each 1and and the flute immediately in front of the same (1. e. 18 w1th I6 a.nd I8 with Hi). The straight and curved portlons of each edge together recede (1. e., extend. clockwise in Fig. 1) from the center of the drill substantially before reaching its circumference. In other words the direction of the edge, when seen in end view, varies through substantially 90 from the center to the perlphen? of the dr1ll. concave clearance surface provldes a. for guiding the chips to the adjacent flute, through which they pass from the work.

It should be noted tha.t each concave clearance surface extends substantiallxr to the center of the drill, each such surface cutting away a portlon of the web but so related that suflicient metal remains on the web to support entt1ng edge. The short or central portlons 22 und 22' o! the cuttlng edge. l. e., those on the web. lle in a. substantlalJy-contlnuous axlal plane. (However, the ed8e cannqt lle exactly in such a plane es 1tis practlcally imposslble to the edges meet in exa.ct allnement at an exa.ct polnt at the geometrlc center of the drlll, elthough In fact. each edze is ofiset from the center by only a. few thousandths o! an inch et the most. 'I'hls oflset ma.y be consldered in. efl!ect es a. sllght web 01 thls dimenslon. Accordingly, although the drlll o! the present invention possesses e, web havlng the strerigth 015 the usual drlll, 112 posses'ses only a slight web at the pe11etratin p01nt whose thickness is practically nfl.)

When viewed a1: rlsht angles to thls axla.l plane.

these edze portlons slant away from the centerof the drll1 to leave a polnt. The rema.lning portlons 24 and 24' 01 the two cuttlng edges are tormed on the forward edge 015 euch land und. therefore, thls portlon of each cuttlng edge is much steeper than the portlon l.ving on the web because lt lies in the 60 cone 015 Fig. 3. It is therefore evident that all parts of cutting edge slam; or taper from the periphery to the axls of the drill to form a polnt; and because of this construction the drill will easlly penetrate ha.rd 01' other wood. In other words, the drlll does not have the usual chlsel edge that lies at rlght angles to the axis o1 the drill und which,

concave clearance surface behind the land und wlthln cone, all cf sa.ld surfacea 01 all ot. the llps meetlng at substantlally the geometrlc center o! the drlll.

2. A double-lipped twlst drlll, l1p havlng two irregularly-shaped dlscontinuous surfaces, one cf which :ls a narrow land, and the other 01 whlch -ls a wider clearance surlace behlnd the land, all 01' sald surfaces meetlng at substantlally the geometrlc center of the drlll.

3. A. double-llpped twlst drlll, each lip havin: two lrregularly-shaped dlscontlnuous surfaees. one ot whlch ls a land, und the other 01 whlch ls e. concave clearance surface behlnd the land, both o! seid surfaces meetlng at substantlally the geometrle center cf the drll1 und the land lylnz in the surfs.ce 015 a cone havlng an lncluded angle of substantlally 4. A twlst drill heving a plurallty of simllar llps spaced equally around the axis 01 the drlll, the llps haVing cuttlng edges whlch taper from the periphery ofthe drill to the axis to Iorm a point, a major portion o! euch edge belng curved in end view a.nd a minor portion belng stralght, and seid straight portlons me eting at sa1d point.

5. A twlst drlll having a plurallty o1 similar lips spaced equally around the axis cf the drlll. 4

the lips ha.ving cutting edges which taper trom the periphery of the drll1 to the a.xl to form a polnt. a major portion 01 euch edge being curved ln'end view and a, minor portlon beim; straight, seid straight pqrtions meeting ab seid point, and the dlrection of each edge, when seen in end vlew, varylng through substantially from the center to the perlphery of the drill.


Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2569874 *Jun 21, 1949Oct 2, 1951Stowell William ERotary carving tool
US3709628 *Oct 19, 1970Jan 9, 1973Osborn Mushet Tools LtdTwist drills
US4065224 *Oct 7, 1976Dec 27, 1977Osborn-Mushet Tools LimitedTwist drills
US4123186 *May 6, 1977Oct 31, 1978Ford Motor CompanyTool for machining clay
US4132493 *Feb 15, 1977Jan 2, 1979Ryosuke HosoiBall end mill
US4602900 *Sep 26, 1983Jul 29, 1986Arpaio Jr JerryMicro drill with modified drill point
US5011342 *Mar 14, 1988Apr 30, 1991501 Greenfield Industries, Inc.Twist drill
US5442979 *Sep 30, 1992Aug 22, 1995Greenfield Industries, Inc.Twist drill
US5735689 *Dec 11, 1995Apr 7, 1998Tycom Dental CorporationEndodontic dental instrument
US5882198 *Jun 30, 1997Mar 16, 1999Ormco CorporationEndodontic instrument having enhanced compliance at the tip
US5902106 *Apr 7, 1998May 11, 1999Ormco CorporationEndodontic dental instrument
US5938440 *Apr 18, 1997Aug 17, 1999Ormco CorporationEndodontic instrument
US5980250 *Dec 11, 1995Nov 9, 1999Tycom Dental CorporationEndodontic instrument
US6293794Feb 16, 1999Sep 25, 2001Ormco CorporationEndodontic instrument having regressive conicity
US6419488Apr 24, 1996Jul 16, 2002Ormco CorporationEndodontic instrument having a chisel tip
US7311480 *Nov 10, 2004Dec 25, 2007Ulf HeulePlate-shaped cutter insert for direct clamping attachment in a base body
US7740427Dec 20, 2007Jun 22, 2010Ulf HeuleDrill plate with a clamping attachment in a base body
US7892235 *Aug 7, 2003Feb 22, 2011Surgibit Ip Holdings Pty LimitedDrill bit and method for producing a drill bit
US8690493 *Aug 12, 2008Apr 8, 2014Mitsubishiki Materials CorporationEnd mill
US20050129473 *Nov 10, 2004Jun 16, 2005Heule, Ulf Ltd.Drill plate with a clamping attachment in a base body
US20050203526 *Aug 7, 2003Sep 15, 2005Ellis Liam P.Drill bit and method for producing a drill bit
US20120148352 *Aug 12, 2008Jun 14, 2012Mitsubishi Materials CorporationEnd mill
U.S. Classification408/230, 144/241
International ClassificationB27G15/00
Cooperative ClassificationB27G15/00
European ClassificationB27G15/00