US2281681A - Work holder for form tools - Google Patents

Description

y J. EDGAR 238M581 WORK HOLDER FOR FORM TOOLS Original Filed Sept. 28, .1934 6 Sheets-5heet l INVENTOR. Jqft/jdf.

g WWW? rm ATTORNEYQ y 1942- J. EDGAR WORK HOLDER FOR FORM TOOLS 6 Sheets-Sheet 2 Original Filed Sept. 28, 1934 a is INVENTOR. \7; V

ATTORNEY-5' May 5, 1942. EDGAR 2,281,681

WORKHOLDER FOR FORM TOOLS Original Filed Sept. 28, 1934 e Sheets-Sheet 3 BY V f z I 1M! I ATTORNEYQ y 1 J EDGAR WORK HOLDER FOR FORM TOOLS Original Filed Sept. 28, 1954 6 Sheets-Sheet 4 n u. w a 5 l INVENTOR.

' n Zc/iq 3' v apvg f vw ATTORNE y 1942- J. EDGAR WORK HOLDER FOR FORM TOOLS Original Filed Sept. 28, 1934 6 Sheets-Sheet 5 INVENTOR.

J l nfa/7qr r w Guru, 67%! W ATTORNEYS y 1942 J. EDGAR WORK HOLDER FOR FORM TOOLS Original Filed Sept. 28, 1934 6 Sheets-Sheet 6 INVENTOR. k7 3i: .2: c/7 a r M, 4; MAM

ATTORNEYJ Patented May 5, 1942 WORK HOLDER FOR FORM TOOLS John Edgar, Rockford, Ill., assignor to Barber- Colman Company, Rockford, 111., a corporation of Illinois Original application September 28, 1934, Serial No. 745,914, now Patent No. 2,181,396, dated November 28, 1939. Divided and this application March 18, 1939, Serial No. 262,595

10 Claims.

This invention relates to mechanism embodying novel work supporting means which is operable in conjunction with grinding means and means for guiding a tool or other device in straight, curved and modified paths particularly adapted for employment in the manufacture of form tools. This application is a division of my copending application Serial No. 745,914, filed September 28, 1934, now Patent No. 2,181,396,

issued November 28, 1939.

There are two principal methods commonly used in the manufacture of form tools, the older of which is the so-called master or fly-tool method. To produce a form tool by this method, it is necessary to make, first, a master or fly-tool which possesses the shape that is desired to be produced by the form tool, but since this fly-tool is made from a piece of unhardened metal and is hardened after being properly shaped, any hardening distortion must be removed by a manual process such as stoning. This method has many disadvantageous features besides being costly.

In view of this, another method has been advanced whereby form tools are ground from hardened pieces of metal by means of abrasive wheels shaped to the proper contour. To correctly shape such an abrasive wheel it has been the custom to employ a templet to which the wheel was trued, the form of the templet not being a, duplicate of the form desired but corresponding to the form desired as corrected to compensate for the clearance angle with which the tool is made, undercut and side clearance or any of them as may be desired on form tools for making straight gash or spiral gash cutters. It results, therefore, as will be more fully described hereinafter, that to make a form tool adapted to produce a circular section it is necessary that the contour of the abrasive wheel used be elliptical, if end clearance alone is to be compensated for, and the contour of the abrasive wheel must be further modified to compensate for the other factors. These features of the invention are covered broadly in the parent application aforesaid.

An object of the invention is to providea novel work holder in a machine which embodies cooperating means for producing plain and modified contours on a grinding wheel, as in compensating for such factors as side clearance, end clearance spiral angle and undercut, which work holder is adapted to support a form tool blank in various positions of adjustment as determined by the contour of the grinding wheel and its proper working relationship to the tool blank.

A further object is to provide a novel work holding device operable in conjunction with an abrasive wheel trued by a dressing mechanism to provide a desired contour on a form tool.

Another object of the invention is to provide, in a machine of this nature having an arbor for supporting a grinding wheel, a support movable transversely of said arbor, means for adjusting the height of said arbor above said support, and means on one end of said support for dressing a wheel on said arbor, new and improved means on the other end of said support for adjustably supporting a work piece for proper cooperation with the grinding wheel.

Further objects and advantages of the invention will become apparent as the description proceeds.

In the drawings:

Figure 1 is a front elevation of a machine embodying the preferred form of the invention.

Fig. 1 is a diagrammatic view of a form tool and a grinding wheel adapted to move at a clearance angle with the plane perpendicular to the cutting surface of the tool.

Fig. 2 is a side elevation looking at the lefthand side of Fig. 1.

Fig. 3 is a fragmental section through the table, work support and tool support, taken in the plane of line 3-3 of Fig. 2.

Fig. 4 is a view along the line 4-4 of Fig. 3.

Fig. 5 is a fragmentary plan view of the undercut control shown along the line 55 of Fig. 3.

Fig. 6 is a front elevation of the mechanism for mounting the tool blank.

Fig. 7 is a plan view thereof.

Fig. 8 is a vertical section along the line 8-8 of Fig. 7.

Fig. 9 is a section along the inclined line 9-9 of Fig. 6. 1

Fig. 10 is a section along the line |0-l0 of Fi 8.

While my invention is susceptible of embodiment in many different forms, I have shown in the drawings and will herein describe in detail one such embodiment, with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiment illustrated. The scope of the invention will be pointed out in the appended claims.

As illustrated in the drawings, an exemplary form of a grinding machine, having a work holder embodying the invention incorporated therein, comprises a supporting bed or base I for a column 2 formed integrally therewith and extending upwardly from the rear portion thereof. A spindle head 3 is slidably mounted on the column and has an arbor or spindle 4 rotatably mounted thereon and extending forwardly from the face of the column and over a platen or table 6 which is movable transversely of the spindle above the knee portion 8 of the machine base.

' Preferably a saddle l is interposed between the (Figs. 1 and 2) which hand wheel drives through 7 amicrometer device (designated generally as I1), and suitable gearing intermediate said micrometer device and the spindle head (not shown). The micrometer-device may be of any suitable form and preferably is of the type shown .in my Patent No. 1,760,932, issued June 3, 1930.

The construction-of themachine thus far described (with the exception of the micrometer device 1'!) is well known to those skilled in the .art, the spindle 4 being generally driven from a motor l8 in the base of the machine by means of a :belt H), which belt engages a pulley 2i) on the spindle shaft and suitable idler pulleys 2i andZ-Z for permitting vertical adjustment of the head on the column.

An exemplary use of a work holder embodying the invention is in connection with a machine having a dressing mechanism A mounted on one end of a table 6. The work or tool holder B is carried by a work support 23 which is slidably mounted on the left-hand portion of the table.

Hence, manipulation of the hand wheel l2 to move the table 6 moves a dressing tool 124 into transversely of the grinding wheel axis for'grinding the blank to the contour which has been formed on the wheel W by the dressing tool.

When grinding form tools, it is necessary to make allowance not only for the end clearance angle to which the tool is ground, but in addition and out of operative relation to the grinding I wheel W and, when the dressing tool has been moved into an inoperative position, reciproeates v.a tool blank 25 mounted in :the work holder B it is sometimes desirable when grinding straight 4 gash tools to provide for undercut or side-clearance or both and when grinding spiral gash tools to provide for the spiral, for undercut and for side clearance. The present adaptation -of the device A so that the conjoint use thereof with the grinding wheel W will cause the tool blank 25 to be formed with the desired end clearance angle, side clearance, undercut and spiral angle. The work holder B will be more fully described hereinafter. Attention will first be directed to the dressing mechanism generally designated A.

The followingdescription of the dressing mechanism, its associated parts and the operation thereof with respect to the grinding wheel will be abbreviated to provide a condensed version of the more complete description thereof found in my said copending application.

The same reference numerals are used in both sets of drawings.

.invention contemplates that the work holder B Y I will be adjustable in correlation with the dressing In Fig. 1 the form tool 2'5 is shown diagrammatically in operative relation with a grinding wheel, the tool being presented to the grinding wheel to provide the tool with an end clearance of angle a. It will be apparent that if the dimension x represents the depth or radius of the cut desired to be reproduced by the tool, it will be necessary to make the depth y measured perpendicular to the clearance end of the tool slightly less than the depth it because of the angular position of the tool during grinding, the dimension y being equal to .r multiplied by the cosine of the angle a. In other words, the contour to be ground on the .tool will be that of an ellipse which ellipse is the projection on a vertical plane of the inclined semi-circle of radius a: which defines the cutting edge of the tool. Thus, the angle a is a clearance angle. A clearance angle may be defined as the angle of recession of the surface of a tool back of its cutting edge relative to a line through said edge extending in the direction of movement of the tool relative to ='the work. If the recession is .on the end of the tool, as in the present instance, it has end clearance; if on the side, it has side clearance.

The mechanism by which the operative movements of the dressing tool 24 are controlled includes a holder 26 for the dressing tool '24 arranged ior free movement in a vertical plane. A head mounted for movement on an axis inclined at the end clearance angle with the horizontal has a connection with the head such that when the head is turned on its inclined axis, the tool h lder 26 will be moved through a curved path which is a horizontal projection of the path of the head. Means 'is provided to modify the path of the dressing tool to compensate for side clearance, undercut and spiral angle as may be desired. The spiral angle of a form tool is the equivalent of the helical angle at the pitch line of the rotary cutter to be produced. In the form tool, this spiral angle is the angle ofinclination of the cutting face laterally of the tool. The undercut in a form tool is the angle of inclination of the cutting face longitudinally of the tool. In the case of a rotary :cutter, the undercut is the angular offset of the cutting face from a radial plane through the cutter axis. The form tool for cutting a rotary cutter having an undercut face, may itself have no undercut, but in such instance has a .form compensated for the undercut on the cutter to be produced.

In each case of a spiral angle, an undercut, and/or a clearance angle, the effective contour .of the grinding wheel .on the work is foreshortsued in some respect. This foreshortening is compensated for .by so changing the contour of the grinding wheel that the foreshortened or distorted form which is applied to the work will be the desired form.

In the illustrated embodiment, the tool holder '26 (Figs. 1 and 3) is mounted on a horizontal shaft 2? which is journaled on a slide 28 supported on a swinging head or arm '29. The arm 29 is mounted swingably upon a pivot '30 secured to :an uprising portion SI of the table 5. The slide '28 is freely movable radially on the swinging arm or head 29, yet its movement is constrained to a vertical plane. These move- .ments may be guided and controlled by means of theshaft Zfl.

The .means which operates through the shaft 21, for guiding :and :moving the tool holder through the desired paths preferably includes a support 32 slidable longitudinally on the table 6. A side clearance control base 33 is pivoted on said support 32 and carries a frame 33 (see Figs. 3 and on which an annular member or barrel 34 is rotatably mounted on an axis inclined at the end clearance angle with the horizontal. A cross slide 35 adjustably mounted within said barrel for movement transversely of its axis carries a rotatably mounted sleeve 36. A shaft 31 is slidable axially in the sleeve, but is suitably held against rotation relative thereto as by balls 3'1 operating in grooves 31'. A head, guide or radius bar 38 on one end of said shaft has a universal connection 39, preferably of a ball and socket type, with the shaft 21 on which the tool holder 26 is mounted.

To compensate for spiral angles and undercutting, the opposite end of the shaft 31 carries a second radius bar 40 having a universal connection 4| with a slide 42 movable radially on a swinging control arm 43 which is pivoted as by a pin 44 on an inclined aXis parallel to the shaft 31. The pin 44 is positioned in the upper end of an adjustably mounted spiral angle control member 45, which member is angularly adjustable upon arcuate ways 46 (Figs. 3 and 5) about an axis perpendicular to the shaft 31. These ways are formed on an undercut control member 41 which in turn is angularly adjustable about an axis perpendicular to the shaft 31 and to the axis of the Ways 46, on arcuate ways 48 formed on a controlsupport 43 mounted on the end of the frame 33 The support 32 is slidably supported, through antifriction elements 32 upon the table 6 for movement transversely of the spindle 4. This provides a freely slidable perpendicular connection between the guiding and compensating means and the tool holder 26 adapted to project, onto the vertical plane of the tool holder, the curve through which the universal connection 39 is moved when positioned radially outward of the axis of shaft 31 since the-connection is constrained to move in' a plane parallel to that of the tool holder. The side clearance control base 33 is pivotally mounted on the support 32 by means of a pivot pin 50 and an annular way 5!. A protractor 52 (Fig. 5) determines the amount of side clearance by the position of the base 33 and clamping bolts 53 secure the parts in an adjusted position.

The frame 33 has a segmental portion 33 mounted on an arcuate Way 33 on the base 33, and comprises a U-shaped end portion (Fig. 5)

extending to the right in the drawings from the segmental portion. The arcuate way 33 is concentric with the shaft 31.

The frame 33 also has arcuate ways 55 concentric with the shaft 31 and arranged to support and guide the barrel 34, the periphery of which is provided with a corresponding guide 56. The periphery of the barrel also has worm wheel teeth 51 (Figs. 1 and a) engageable by a worm 57 on a manually operable shaft 58 rotatably mounted the base frame 33 The cross slide 35 is mounted on rectilinear ways 55 extending transversely of the barrel so that the shaft 31 may be moved diametrically across the barrel. A cross feed screw 30 (Figs. 1 and 3) is arranged to engage a nut Bl on the cross slide manipulable through a squared end 62 for adjusting the cross slide transversely of the barrel,

The rotatable sleeve 33 is suitably secured against longitudinal movement and may be rotated by means of a manually operable worm 63 on a shaft I53 (Figs. 1, 3 and 4) which engages a worm wheel 64 secured to the sleeve and has squared outer ends 65. The sleeve may be locked in its normal position by means of a spring operated plunger 66.

The radius bars 38 and 43 are secured in a common longitudinal plane through the axis of the shaft 31. The radius bar 38 has a slide it which is adjustable radially thereon and secured by suitable clamping bolts H (Fig. 1). This slide it supports one member I2 of the universal joint 39 and the other member 13 is secured to the tool holder shaft 21. The structure associated with the radius bar 40 may substantially duplicate that just described. Thus, the radius bar 40 has a radially adjustable slide 14 secured by bolts 15. This slide carries one member 76 of the universal joint 4 I the other member ll being secured to a shaft 18 rotatably mounted on the slide 42 carried by the swinging arm 43.

The various adjustments which have been described function severally or jointly to produce the movement of the dressing tool through such a path relative to the grinding wheel as will develop a required contour on the wheel. Since this contour may be variously modified, the work or tool blank holder B must be capable of adjustment to properly correlate the relationship of the tool blank with the grinding wheel. The new and improved work holder which embodies the features of invention covered herein includes adjustments whereby the work holder may be set quickly and accurately to positions conforming to and initially determined by the adjustments of the dressing tool.

Referring particularly to the structure of the work holder B, the work support 23 is slidably mounted on the uprising portion 3| of the table 5 along ways 80 for movement transversely of the grinding wheel spindle 4 so that after the grinding wheel W has been properly dressed, the tool blank holder B may be traversed across the grinding wheel without moving the table. This traverse movement may be imparted to the work support 23 manually by any suitable means, which means preferably includes a hand wheel 8! rotatably mounted on the table portion 3| and readily accessible to an operator standing in front of the machine.

The work support B, as shown in Figs. 6 to 10, comprises a circular base I00 rotatably mounted on the upper surface of the support 23 by means of a pivot bolt HO and an annular guide ring Ill. The guide ring may be adjusted angularly with respect to the support 23 as indicated on a scale It)! and may be secured in its adjusted position by means of the pivot bolt. A spring pressed plunger or index pin H2 carried on the base I30 is adapted to engage either one of two sockets H3 positioned apart in the ring I i I. Extending upwardly from the base i953 and formed integrally therewith are a pair of inclined brackets H4. A body member H5 is positioned intermediate said brackets and pivotally mounted on a horizontal shaft I04 mounted in the brackets. The pivotal mounting is provided for permitting modification of the end clearance angle to which the tool blank 25 is ground, the upper portion of the member I 15 carrying clamping bolts IE6 passing through slots Ill in the brackets H4 to secure the body member in its adjusted position as determined by a scale H8.

A centrally apertured disk us is secured to the body member H5 and is provided with an annular T-slot I and a central boss I2I. An angularly adjustable member or head I22 has a shoulder engaging said boss and carries a plurality of bolts I23 with their heads in said T-slot so that the head I22 may be clamped in its adjusted position on the disk II9 as determined by an indicating scale N52. The head I22 is provided with rectilinear guides I23 normally positioned horizontally and carrying a cross slide I24 having corresponding ways I25. A somewhat circular tool blank supporting member E26 is angularly adjustable on the cross slide I24, being positioned thereon by means of a boss I21 on the cross slide and being adapted to be clamped in its adjusted position, as determined by a scale I63, by means of a plurality of bolts I23. Suitable means, such for example as a notch I29 and clamping bolt I39, may be provided for securing the tool blank to the supporting member H6.

The cross slide I24 may be adjusted on the guides I23 to displace the tool blank longitudinally of the grinding spindle 4 by means of a feed screw i3I (Fig. 9) non-rotatably supported on the cross slide and engaged by a nut I32 rotatably mounted on the head I22. This nut has a bevel pinion I 33 thereon engaging a second bevel pinion I34 mounted on one end of a shaft I35. A Worm wheel I36 on the shaft I is driven by a Worm 53'! on the shaft Ili l to move the cross slide.

The shaft I35 preferably extends outwardly of the body member H5 to operate a micrometer device designated generally I38 by which the position of the cross slide may be indicated. The amount of the displacement of the tool blank by movement of the cross slide may be determined by the difference between the two readings on the micrometer device I38.

-As described hereinbefore, the dressing mechanism A and the tool blank or work holder B are generally constructed at a standard or desired end clearance angle, the dressing mechanism being so set to compensate for the modified form required on the grinding wheel because of the end clearance angle, and the work holder being so set to insure grinding of the tools to the desired clearance angle. Form cutters of the straight gash type are the simplest for which to grind form tools. The setup of the machine for grinding form tools for this type of cutter will therefore be described first.

The setup of the tool blank is particularly simple as the work holder, with the protractors indicating zero, holds the tool blank parallel to the table 6 and perpendicular to the grinding wheel spindle. The dressing mechanism is also set at zero except to the angle of form. Thus, the protractors 90, ill and 92 on the side clearance, spiral angle and undercutting controls respectively are at zero and the slides Hi and M are central of the radius bars 38 and All respectively, as illustrated herein. The dressing fixture is set to the desired angle of form by rotating the barrel 34. With the dressing tool in the vertical plane through the axis of the wheel W, feeding movement of the dressing tool may be accomplished by actuating the cross slide 35, the head 3 being lowered to cause the tool to engage the wheel. Following the dressing operation, the work holder is moved through a working stroke relative to the grinding wheel and the form, which has been set up by the adjustments of the dressing device, is produced on the work blank.

For straight gash cutters with undercut faces, the setting of the dressing mechanism is the same except that the undercut control member 47 is set at an angle of negative rake. The negative rake referred to is not the undercut angle on the cutter but is the angle to which it is necessary to dress the grinding Wheel to give the proper foreshortening on the form tool. The angle is a function of the undercut angle on the cutter, the clearance angle on the form tool, the clearance angle on the cutter tooth and the diameter of the cutter. An empirical equation can readily be set up and by means of a simple calculation, the proper angle for setting the undercut angle control member ll may be obtained.

For grinding a straight gash cutter form tool with side clearance, the work holder is adjusted so that the tool blank is set at an angle other than the standard clearance angle depending upon the angle of side clearance. Thus, the head I26 is set at a slight angle to the vertical about the inclined axis of the work holder, this angle corresponding to the angle of side clearance. The tool blank is also swung horizontally at a suflicient angle on the scale IilI to give the proper side clearance angle. The form dressed upon the grinding wheel is the same as for straight gash cutters, the position of the tool blank while being ground making provision for obtaining the desired shape on the face of the tool.

In order to grind form tools for straight gash cutters having both side clearance and undercut faces, the tool blank is set the same as for grinding form tools with side clearance and the dressing fixture is set the same as for dressing grinding Wheels for cutters with undercut faces. This combination dressing of the grinding wheel for undercut and positioning the tool blank for side clearance produces a form tool, the face of which is correct for cutting this type of cutter.

To grind tools for spiral gash cutters, the tool blank is set at the standard end clearance angle with the protractors oi the Work holder set at zero. The head 1255 is set at the tip angle corresponding to the clearance and gash angles. In the dressing mechanism, the spiral control member i5 is set at the angle of the required gash. Since the head I26 is tipped, the tool blank is brought to the proper height to compensate for the spiral gash.

When grinding tools for spiral gash cutters with undercut faces the tool blank is set as for spiral gash cutter tools as just described. The dressing mechanism, in addition to having the spiral control member i5 set as just described, also has the undercut control member 41 set at the required angle of negative rake.

In grinding form tools for spiral gash cutters with side clearance, the head i26 of the tool holder is set at an angle to the vertical depending upon whether right or left hand spiral gash as well as whether right or left hand side clearance is desired, after which the tool blank is swung horizontally about the pivot lid through the angle corresponding to the required side clearance angle. The dressing mechanism is then swiveled on its pivot 59 so that the axis of the barrel 3% is perpendicular to the back of the tool blank and the spiral control member 45 is set parallel with the face of the tool blank, the angle of which will be either the combined angles of spiral and side clearance or their difference.

For grinding form tools for spiral gash cutters with both undercut faces and side clearances, the

tool blank is set as described for form tools for spiral gash cutters with side clearance. The dressing mechanism is set as described, and. with the undercut control member 41 set at the proper angle.

In producing some form tools, combinations of the foregoing settings will be necessary but in each instance the work holder may be accurately adjusted for coaction with a grinding wheel having a contour determined by the adjustment of the dressing device.

I claim as my invention:

1. A work holder of the character described comprising, in combination, a support, an annular ring adjustable angularly on said support, a base pivotally mounted on said support guided by said ring, a pair of brackets inclined upwardly from said base, a body member mounted on a horizontal shaft extending through said brackets for limited swinging movement from a normal clearance angle inclination, a head angularly adjustable on said body member about its inclined axis, a cross slide on said head movable transversely of said axis, and a tool blank supporting member rotatably mounted on said slide,

2. A work holder of the character described comprising, in combination, a support, a base pivotally mounted on said support about a vertical axis, bracket means inclined upwardly from said base, a body member mounted on a horizontal shaft supported by said bracket means for limited swinging movement from a normal clearance angle inclination, a cross slide carried by said body member movable transversely of said axis, and a tool blank supporting member rotatably mounted on said slide.

3. A work holder of the character described comprising, in combination, a support, a base pivotally mounted on said support, a pair of brackets inclined upwardly from said base, a body member mounted on a horizontal shaft extending through said brackets for limited swinging movement, a head angularly adjustable on said body member about an axis perpendicular to said shaft, a cross slide movable diametrically on said head, and a tool blank supporting member adjustably mounted on said slide.

4. A work holder for a machine having a grinding wheel which is dressed to a modified form including a compensation for one or more of such factors as side clearance, end clearance, spiral angle and undercut, said work holder having, in combination, a reciprocable support, and means for mounting a Work blank on said support including a supporting member for adjusting said work blank to a predetermined angle of end clearance inclination, and adjustable means for varying the position of said blank rotatably and transversely with respect to the plane of the angle of inclination as required by the presence of compensation for said factors in the form of the grinding wheel.

5. A work holder for a machine having a grinding wheel which is dressed to a modified form including a compensation for one or more of such factors as side clearance, end clearance, spiral angle and undercut, said Work holder having, in combination, a reciprocable support, means for mounting a work blank on said support including a member for supporting said work blank at an angle of end clearance inclination, and means movable on a plane paralleling the angular plane of end clearance inclination for adjusting said work blank in a direction generally transverse horizontally of the line of support reciprocation and in the plane of the angular position of the work blank.

6. A Work holder for a machine having a grinding wheel which is dressed to a modified form including a compensation for one or more of such factors as side clearance, end clearance, spiral angle and undercut, said work holder having, in combination, a reciprocable support, means for mounting a work blank on said support including a member for supporting said work blank at an angle of end clearance inclination, and means for adjusting said work blank rotatably and horizontally in its angular plane.

'7. A work holder for a machine having a grinding wheel which is dressed to a modified form including a compensation for one or more of such factors as side clearance, end clearance, spiral angle and undercut, said work holder having, in combination, a reciprocable support, means for mounting a work blank on said support including a member for supporting said work blank at an angle of end clearance inclination, means for adjusting the work supporting means rotatably about a vertical axis, means for adjusting the work blank horizontally in a direction transverse of the line of support reciprocation, and means for adjusting the work blank rotatably in the plane of its angular position.

8. A work holder of the character described comprising, in combination, a support, a .base pivotally mounted on said support about a vertical axis, a body member mounted on said base for relative pivotal movement on a horizontal axis to provide limited swinging movement from a normal clearance angle inclination, a cross slide carried by said body member, and a tool blank supporting member adjustably mounted on said slide.

9. A work holder of the character described comprising, in combination, a base, bracket means extending upwardly from said base, a body member, a shaft pivotally supporting said body member on said bracket means for limited swinging movement from a normal clearance angle inclination, and adjustable tool supporting means including a cross slide on said body member, and driving means interposed between said shaft and said cross slide for effecting reciprocatory adjustment of said cross slide.

10. A work holder for a machine having a grinding wheel which is dressed to a modified form including a compensation for one or more of such factors as side clearance, end clearance spiral angle and undercut, said work holder having, in combination, a reciprocable support, and means for mounting a work blank on said support including adjustable means for fixing the position of the face of the work blank to be ground at a predetermined angle of inclination with respect to said support and for effecting rotational and rectilinear adjustment of the position of said tool blank with respect to the angle of inclination.

JOHN EDGAR.

Images