US3626645A - Method of sharpening twist drills - Google Patents

Method of sharpening twist drills Download PDF

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Publication number
US3626645A
US3626645A US865299A US3626645DA US3626645A US 3626645 A US3626645 A US 3626645A US 865299 A US865299 A US 865299A US 3626645D A US3626645D A US 3626645DA US 3626645 A US3626645 A US 3626645A
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US
United States
Prior art keywords
twist
drill
grinding
sharpening
point
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US865299A
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English (en)
Inventor
Claude Rochet
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Renault SAS
Regie Nationale des Usines Renault
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Renault SAS
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Publication date
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Publication of US3626645A publication Critical patent/US3626645A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23B—TURNING; BORING
    • B23B51/00—Tools for drilling machines
    • B23B51/02—Twist drills
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B3/00—Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools
    • B24B3/24—Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools of drills
    • B24B3/26—Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools of drills of the point of twist drills
    • B24B3/32—Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools of drills of the point of twist drills for thinning the point
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23B—TURNING; BORING
    • B23B2251/00—Details of tools for drilling machines
    • B23B2251/18—Configuration of the drill point

Definitions

  • the present invention relates to an improved method of sharpening twist drills notably of the type used for drilling metals and alloys, and is directed to increase the wear resistance of the twist drill tip as well as the drilling precision of these tools.
  • Sharpening a twist drill according to conventional methods comprises as a rule two separate steps:
  • This sharpening method is characterized in that the twist drill point is ground to impart a pyramidal configuration thereto, this pyramid-like point being centered automatically to the twist drill axis.
  • a first grinding plane provides a ground surface giving the rake angle of the cutting lip; a second grinding plane provides another relief surface behind the rake surface, and a third grinding plane cuts radially towards the outer diameter a limited portion of the web.
  • the facet formed by said first and third planes in all the twist drill lips constitute the above-mentioned point pyramid wherein the edges forming the major angle are the negative cutting edges in the web region.
  • the acute-angle edges of the pyramid operate as actual negative cutting elements, thus eliminating any detrimental metal driving effect.
  • the twist drill web can be reinforced without any inconvenience as far as the metal cutting action is concerned, thus affording a faster and more accurate drilling for a lesser power consumption, together with a reduced wear.
  • FIG. 1 is an end view of the twist drill point sharpened according to the method of this invention
  • FIG. 2 is an elevational view of the tip of the twist drill shown in FIG. 1;
  • FIG. 3 is a perspective view showing a device for sharpening twist drills according to the method of this invention, this device comprising one grinding wheel and one twist-drill positioning support, and
  • FIGS. 4 and 5 show diagrammatically, respectively in elevation view and in lateral view, a three-grinding wheel sharpening device, these two views being however independent.
  • FIGS. 1 and 2 it will be seen that to obtain a proper point 1 of a twist drill 2 for example of the type comprising two lips 3 and 3 providing the cutting edges, the sharpening or grinding operation is carried out in three grinding planes or surfaces for each cutting edge of the point, the same planes being obtained for the opposite or symmetric cutting edge by turning the twist drill through about its axis.
  • a first grinding plane provides the rake of lip 3 by forming a facet 4.
  • a second grinding plane provides a lip relief facet 5 behind the rake facet 4.
  • a third grinding plane provides a radial limitation, towards the outer diameter, of the twist-drill web region by cutting this region to form a facet 6.
  • the planes of both facets 5 and 6 intersect the plane of facet 4 along a common straight line 7 lying in a plane containing the twist-drill axis A-A and constituting the point cutting edge.
  • the facets 4, 6 and 4 6 of the two symmetric lips 3 and 3 constitute the faces of the pyramid.
  • the edges 7, 7 8 and 8 form at their intersection the vertex of the pyramid constituting the self-centering point of the twist-drill, which is located exactly on the axis of the twist-drill.
  • the above-described three surfaces are ground by using a straight-type cup grinding wheel.
  • the rakes are constant along the cutting edges in a plane perpendicular to these edges.
  • the edges forming the major angle are the negative cutting edges in the web portion of the twistdrill.
  • the sharpening operation is carried out by generation on the working face of the straight-type cup-shaped grinding wheel, thus eliminating any diamond-shaping or dressing of this face for performing this operation.
  • the sharpening operation according to the method of this invention can be carried out on conventional twist-drill sharpening machines, as will be described hereinafter with reference to specific examples.
  • the twist-drill sharpening device illustrated diagrammatically in FIG. 3 comprises a single cup-shaped grinding wheel 9 rotatably driven about the axis of its shank 10 but held in a fixed position.
  • the vertical plane of the grinding face 11 of this Wheel comprises the horizontal axis B-B about which the E- shaped support 12 of the twist-drill carrier 13 is pivotally mounted; this axis BB is coincident with the straight lines 7, 7 converging to the vertex of the twist drill 2.
  • the bed 14 supporting the support 12 is movable horizontally as shown by the arrows f and 1.
  • the twist-drill support 12 can be set to pivot through different angular amplitudes about the axis BB for grinding the sharpening surfaces 4, 5 and 6 described hereinabove.
  • the twist-drill carrier 13 proper is adapted to pivot about a pivot pin 15 carried by the support 12 for accurately adjusting the point angle.
  • An adjustable stop (not shown in the drawing) is also provided for limiting the movement of translation of the bed 14 and therefore the width of the face 6 cut in the web region.
  • the axis A-A of twist-drill 2 and the axis CC about which the twist-drill carrier is pivoted converge to a point I on axis B--B about which the E-shaped support 12 is pivotally mounted.
  • a stop 16 lying in the vertical grinding plane is scored with parallel horizontal lines and angularly adjustable to permit of indexing the twist-drill in a preselected position before commencing the sharpening operation in order to restore the cutting edge in a horizontal plane upon completion of the sharpening or grinding operation.
  • a diamond point 17 is provided for dressing the grinding wheel 9 after taking up the wear.
  • the device and method described hereinabove are applicable to all sharpening machines providing two perpendicular motions, i.e. one for the feed movement along the grinding wheel surface and the other for adjusting the grinding wheel feed movement.
  • a three-grinding wheel sharpener of the type illustrated diagrammatically in FIGS. 4 and 5 may advantageously be used for carrying out the method of this invention, as this arrangement greatly simplifies the twist-drill mountmg.
  • each grinding wheel is rotatably mounted on a common stationary semi-cylindrical cradle 21 on which each grinding wheel can be set angularly according to the values of the threegrinding planes to be obtained.
  • grinding wheel 18 will grind the facet 4, grinding wheels 19 and 20 (of which only the axes of rotation are shown in FIG. 5) being used for grinding the facets 5 and 6 of the twist-drill point.
  • the axes of rotation of these grinding wheels 18, 19 and 20 intersect the axis B-B about which the supporting cradle 21 is pivotally mounted where the three planes generated by the working edges of wheels 1-8, '19 and 20 intersect each other.
  • a diamond 17 rigid with each grinding-wheel support 22 permits the dressing or adjustment of each wheel, each grinding wheel is adjustable for translation along its axis of rotation 10.
  • a support 23 on which the carrier 24 of twist-drill holder 13 is movable angularly in a plane containing the axis B-B permits the adjustment of the point angle of the twist-drill.
  • a laterally movable bed 14 provided with adjustable stops (not shown) permits the movements of translation of the twist-drill 2 past the grinding wheels 18, 19 and 20.
  • An optical device 25 is also provided for indexing the twist-drill.
  • the carrier 24 of the twist-drill holder is provided with a graduated scale (not shown).
  • a method of sharpening twist-drills having a point, at least two lips symmetric in regard to a longitudinal axis of the twist-drill each with an end part comprising the web of the drill, a cutting edge adjacent to surfaces forming a rake, said end parts of the lips forming a point having a pyramidal configuration with a vertex centered automatically to the twist-drill longitudinal axis, grinding said configuration of said end parts of all lips in the following steps, grinding along a first plane providing a first facet forming the cutting edge of the lip and giving the rake of the lip, grinding along a second plane providing a second relief facet behind said first facet, and grinding along a third plane cutting radially toward the outer circumference of said point an area limited by said web of the twist-drill, the facets formed by said first and third grinding steps in all said twist-drill lips constituting said pyramidal point wherein the cutting edges form the pyramid edges, those of the edges thereof forming the greatest angle being negative cutting edges of the web
  • twist-drills according to claim 2, wherein the twist-drill to be sharpened is movable bodily in translation parallel to a horizontal axis coinciding with said straight line on which said three grinding planes grinding said three facets intersect, said grinding planes being performed by three separate grinding means each adjustable to a proper angular position about said horizontal axis, the complete sharpening of a radial cutting edge of said twist-drill point being performed by a single adjustment of the angular position and by a singular movement of translation of said twist-drill limited by a stop for the grinding of said third facet in the web region.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
  • Drilling Tools (AREA)
US865299A 1968-10-18 1969-10-10 Method of sharpening twist drills Expired - Lifetime US3626645A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR170457 1968-10-18

Publications (1)

Publication Number Publication Date
US3626645A true US3626645A (en) 1971-12-14

Family

ID=8655818

Family Applications (1)

Application Number Title Priority Date Filing Date
US865299A Expired - Lifetime US3626645A (en) 1968-10-18 1969-10-10 Method of sharpening twist drills

Country Status (10)

Country Link
US (1) US3626645A (xx)
JP (1) JPS505433B1 (xx)
BG (1) BG21002A3 (xx)
DE (1) DE1952217C3 (xx)
ES (1) ES372264A1 (xx)
FR (1) FR1589568A (xx)
GB (1) GB1282327A (xx)
HU (1) HU165984B (xx)
NL (1) NL6915658A (xx)
YU (1) YU33151B (xx)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3838540A (en) * 1972-06-05 1974-10-01 J Steinmetz Apparatus for sharpening drills and other cutting tools
JPS49112291A (xx) * 1973-02-10 1974-10-25
US3916582A (en) * 1973-06-20 1975-11-04 Marcel Costil Cutting-tool grinding method
EP0046833A1 (de) * 1980-08-29 1982-03-10 Christen AG, Wabern Bohrspitzen-Schleifmaschine
US5146669A (en) * 1991-07-31 1992-09-15 Fabiano Joseph F Method of manufacturing an insert drill
WO2000044530A1 (en) * 1999-01-29 2000-08-03 Intertool Machines Ltd. Universal sharpening apparatus employing pair of arcuate bearings
US6450864B1 (en) * 2000-10-13 2002-09-17 Raphael W. Smith End mill grinder with two independently adjustable grinding wheels
WO2004014241A1 (en) 2002-08-08 2004-02-19 Liam Patrick Ellis A drill bit and method for producing a drill bit
CN101642382B (zh) * 2002-08-08 2014-01-01 瑟吉比特Ip控股有限公司 钻头
CN104907611A (zh) * 2014-03-13 2015-09-16 钴碳化钨硬质合金公司 一种旋转工具,特别是一种钻孔工具,以及制造旋转工具的方法

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IL64173A (en) * 1981-10-30 1984-03-30 Etm Eng Tool Mfg Co Ltd Machine for grinding points of drills
DE3202362C2 (de) * 1982-01-26 1986-05-22 Fa. Gottlieb Gühring, 7470 Albstadt Vorrichtung zum Ausspitzen eines Wendelbohrers
GB2146925A (en) * 1983-09-23 1985-05-01 Microcut Machine Tools Limited Drill point grinding machine
KR950031335A (ko) * 1994-05-13 1995-12-18 아키모토 유우미 드릴
DE19955172A1 (de) * 1999-11-16 2001-05-23 Kennametal Inc Verfahren zum Schleifen einer Bohrspitze und Bohrerspitze
JP5217031B2 (ja) * 2008-07-01 2013-06-19 ニシガキ工業株式会社 ドリルチャック及びドリル研磨機

Cited By (28)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3838540A (en) * 1972-06-05 1974-10-01 J Steinmetz Apparatus for sharpening drills and other cutting tools
JPS49112291A (xx) * 1973-02-10 1974-10-25
US3894358A (en) * 1973-02-10 1975-07-15 Kapp & Co Mounting arrangement for a grinding wheel dressing device
JPS56167B2 (xx) * 1973-02-10 1981-01-06
US3916582A (en) * 1973-06-20 1975-11-04 Marcel Costil Cutting-tool grinding method
EP0046833A1 (de) * 1980-08-29 1982-03-10 Christen AG, Wabern Bohrspitzen-Schleifmaschine
US5146669A (en) * 1991-07-31 1992-09-15 Fabiano Joseph F Method of manufacturing an insert drill
US5302059A (en) * 1991-07-31 1994-04-12 Fabiano Joseph F Insert drill
WO2000044530A1 (en) * 1999-01-29 2000-08-03 Intertool Machines Ltd. Universal sharpening apparatus employing pair of arcuate bearings
US6450864B1 (en) * 2000-10-13 2002-09-17 Raphael W. Smith End mill grinder with two independently adjustable grinding wheels
US20090216235A1 (en) * 2002-08-08 2009-08-27 Surgibit Ip Holdings Pty Limited Drill bit and method for producing a drill bit
US8162945B2 (en) 2002-08-08 2012-04-24 Surgibit Ip Holdings Pty Limited Drill bit and method for producing a drill bit
US20050203526A1 (en) * 2002-08-08 2005-09-15 Ellis Liam P. Drill bit and method for producing a drill bit
EP1528892A4 (en) * 2002-08-08 2009-07-01 Surgibit Ip Holdings Pty Limit TREPAN AND PROCESS FOR PRODUCING A TREPAN
WO2004014241A1 (en) 2002-08-08 2004-02-19 Liam Patrick Ellis A drill bit and method for producing a drill bit
US20090222009A1 (en) * 2002-08-08 2009-09-03 Surgibit Ip Holdings Pty Limited Drill bit and method for producing a drill bit
US7892235B2 (en) 2002-08-08 2011-02-22 Surgibit Ip Holdings Pty Limited Drill bit and method for producing a drill bit
EP2399530A1 (en) * 2002-08-08 2011-12-28 Surgibit Ip Holdings Pty Limited Drill bit
EP2399531A1 (en) * 2002-08-08 2011-12-28 Surgibit Ip Holdings Pty Limited Drill bit
EP1528892A1 (en) * 2002-08-08 2005-05-11 Liam Patrick Ellis A drill bit and method for producing a drill bit
US8172845B2 (en) 2002-08-08 2012-05-08 Surgibit Ip Holdings Pty Limited Drill bit and method for producing a drill bit
CN101642382B (zh) * 2002-08-08 2014-01-01 瑟吉比特Ip控股有限公司 钻头
US11337709B2 (en) 2002-08-08 2022-05-24 Surgibit Ip Holdings Pty Limited Drill bit and method for producing a drill bit
EP2918360A1 (de) * 2014-03-13 2015-09-16 Kennametal Inc. Rotationswerkzeug, insbesondere bohrwerkzeug sowie verfahren zur herstellung eines rotationswerkzeuges
US9604285B2 (en) 2014-03-13 2017-03-28 Kennametal, Inc. Rotary tool and method for manufacturing
CN104907611B (zh) * 2014-03-13 2020-04-10 钴碳化钨硬质合金公司 一种旋转工具，特别是一种钻孔工具，以及制造旋转工具的方法
DE102014204700B4 (de) 2014-03-13 2022-02-17 Kennametal Inc. Rotationswerkzeug, insbesondere Bohrwerkzeug sowie Verfahren zur Herstellung eines Rotationswerkzeuges
CN104907611A (zh) * 2014-03-13 2015-09-16 钴碳化钨硬质合金公司 一种旋转工具,特别是一种钻孔工具,以及制造旋转工具的方法

Also Published As

Publication number Publication date
FR1589568A (xx) 1970-03-31
GB1282327A (en) 1972-07-19
JPS505433B1 (xx) 1975-03-04
YU251569A (en) 1975-12-31
HU165984B (xx) 1974-12-28
DE1952217B2 (de) 1979-09-20
DE1952217A1 (de) 1971-03-25
BG21002A3 (xx) 1976-01-20
ES372264A1 (es) 1971-09-16
YU33151B (en) 1976-06-30
NL6915658A (xx) 1970-04-21
DE1952217C3 (de) 1980-05-29

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