US2792823A

US2792823A - Sine-bar arrangement and fixture for cutting a radial clearance form on grinding wheel peripheries

Info

Publication number: US2792823A
Application number: US443271A
Authority: US
Inventors: Muench Walter
Original assignee: WALTER MUENCH Inc
Current assignee: WALTER MUENCH Inc
Priority date: 1954-07-14
Filing date: 1954-07-14
Publication date: 1957-05-21
Anticipated expiration: 1974-05-21

Description

MUENCH May 21, 1957 W. SINE-BAR ARRANGEMENT AND FIXTURE FOR CUTTING A RADIAL CLEARANCE FORM ON GRINDING WHEEL PERIPHERIES 5 Sheets-Sheet l llll lllllll Filed July 14, 1954 INVENTOR [UaZZer Maerzch ATTORNEYS May 21, 1957 w, MUENCH 2,792,823

SINE-BAR ARRANGEMENT AND FIXTURE FOR CUTTING A RADIAL CLEARANCE FORM ON GRINDING WHEEL PERIPHERIES Filed July 14, 1954 3 Sheets-Sheet 2 ATTORNEYS 2,792,823 RADIAL ES 5 Sheets-Sheet 3 May 21,1957 w. MUENCH SINE-BAR ARRANGEMENT AND FIXTURE FOR CUTTING A CLEARANCE FORM ON GRINDING WHEEL PERIPHERI Filed July 14. 1954 wnN ' w mum/r01? ll/aZZer Muerzck J 22 Q A'ITOKNEYS I wimb Jnited States Patent SINE-BAR ARRANGEMENT AND FIXTURE FOR CUTTING A RADIAL CLEARANCE FORM ON GRINDING WHEEL PERIPHERIES Walter Muench, Newark, N. J., assignor to Walter Muench, Incorporated, Newark, N. J., a corporation of New Jersey Application July 14, 1954, Serial No. 443,271

11 Claims. (Cl. 125-11) The invention relates generally to fixtures for supporting cutting diamonds in a manner for cutting a radial clearance form on grinding wheel peripheries and primarily seeks to provide a novel arrangement including a readily adjustable and secured sine-bar support.

Cutting diamond supporting devices of the general character stated have been known heretofore. One known structure includes a U-shaped base and a U-shaped swing block swingably mounted on the base and having provision thereon for carrying the cutting diamond. in such devices, when it has been desired to place the axis of swinging movement of the swing block at an incline to the horizontal it has been necessary to employ a separate, conventional sine-bar as an underlying support for the base, and to tilt the bar in the desired amount by resting the same upon gage blocks. If secure clamping was in contemplation, separable clamp devices subject to loosening as a result of Vibration were utilized.

In an improved arrangement covered in my earlier United States Letters Patent 2,642,059, issued June 16, 1953, sine-bar characteristics were incorporated by providing on the swing block a swingably mounted and calibrated cutting diamond carrying saddle. While this arrangement was very eflicient and provided desired sinebar characteristics directly in the fixture, the degree of angular adjustment of the saddle was limited by placement thereof on the base portion and between the upstanding arms of the U-shaped swing block.

It is a purpose of the present invention to provide an additionally improved arrangement of the character stated wherein the sine-bar characteristics are built directly into the fixture and yet provision is made for relatively wide angle adjustment, fully sufiicient for any possible requirements in shop work.

-In its more detailed nature the invention resides in providing in a fixture or apparatus of the character stated, a U-shaped base member comprising a base portion and a pair of upstanding support arms, a U-shaped swing block comprising a base portion and a pair of upstanding mounting arms disposed between the support arms, bearing means swingably supporting the mounting arms on the support arms, the spacing of the mounting arms providing a central space in which to accommodate projection of a work piece, a diamond carrier, a cutting diamond on the carrier and projecting into the space between the mounting arms, means supporting the carrier on the swing block base portion, sine-bar disk means mounted on the base member base portion in position for engagement with angle determining gage block means,

and means for securing the base member in selected gage,

block determined position-s.

An object of the invention is to provide an apparatus of the character stated wherein the sine-bar disk means are directly secured to the base portion of the base member in adjustable spaced relation.

Another object of the invention is "to provide an apparatus of the character stated wherein'the sine bar disk means and the base member have complementary mounting socket and mounting projection portions and said disk means are magnetically retained on the base member base portion.

A further object of the invention is to provide an apparatus of the character stated wherein the means for securing the base member in selected gage block determined positions comprises a base plate, upstanding brackets secured in spaced relation on the base plate, means for securing the brackets on the base plate in varied selected spaced relations, and means for securing end portions of the base member base portion at varied selected heights on the brackets.

A still further object of the invention is to provide an apparatus of the character stated wherein there is included a support plate slidable along the base plate and whereon to receive gage blocks.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawings.

In the drawings:

Figure 1 is a front elevation illustrating a radiusdresser embodying the invention.

Figure 2,is a plan view illustrating the radius-dresser shown in Figure 1.

Figure 3 is a View similar to Figure 1 illustrating the U-shaped base member and the U-shaped swing block supported thereon adjusted to an angular position with relation to the horizontal.

Figure 4 is a View similar to Figure 1 illustrating a modified arrangement including magnetically attached sine-bar disks.

Figure 5 is a fragmentary plan view illustrating the left hand end portion of the arrangement. shown in Figure 4.

Figure 6 is a fragmentary front elevation illustrating another modified arrangement of magnetically attached sine-bar disks or measuring plugs.

Figure 7 is a detail perspective view illustrating the sine-bar disk means magnetically attached to the left hand end portion of the U-shaped base member base portion shown in Figure 6.

Figure 8 is a fragmentary central vertical cross sectional view illustrating the mounting of the centrally disposed, magnetically attached sine-bar disk means of Figure 6.

Figure 9 is a detail perspective view illustrating the sine-bar disk means of Figure 8.

In the example disclosure of the invention illustrated in Figures 1 to 3, the arrangement includes a U-shaped base member 5 having a base portion 6 and upstanding parallel spaced support arms 7. There is also included a swing block 8 having a base portion 9 and upstanding parallel spaced mounting arms 10 disposed between the support arms 7 and swingably mounted thereon at 11. A diamond carrier 12 is secured at 13 on the base portion 9 ,of the swing block and carries a long cutting edge cutting diamond 14 projecting into the space between the arms 10 into which the work piece 15 projects. In the illustration in Figures 1 and 3 the work piece cemprises a grinding wheel on an axis indicated at a.

A base plate 1-5 is provided having an upstanding positioning rib i7 extending centrally therealong, and a row of selective, internally threaded bores 18 is provided along the base plate at each side of the central rib 17, as will be clearly apparent by reference to Figure 2.

Two brackets generally designated 19 and 2d are provided and mounted atthe respective ends of the base plate 16 as illustrated in Figures 1,2 and 3.

The bracket 19 includes a base 21 and an upstanding support wall 22, the latter being equipped with an upright slot 23. The base 21 has a bottom face groove 24 in which to receive the base plate rib l7, and longitudinal slots 25 overlying the rows of bores'lfi and through which to receive securing screws 26 which are selectively threadable into the bores for securing the bracket 19 at selected positions along the base plate 16.

Bolt means 2'7 passing through a hole or cross bore 23 provided in the base portion 6 of the base member and through the bracket slots 23 serves to adjustably secure the base portion 6 on the bracket 19, and the head 29 on said bolt means serves the purpose of a sine-bar means.

Another selective cross bore 39 is provided in the base portion 6 of the base member and its axis is spaced from the axis of the cross bore 28 a distance of five inches in the practical use of the fixture. A third selective cross bore 31 is provided in the base portion 6 of the base member and is placed so that its axis is spaced ten inches from the axis of the cross bore 28 in the practical use of the fixture. The cross bores 30 and 31 are adapted to selectively receive a cross bore screw or pin 32, the head 33 of which serves as another sine-bar disk means for cooperating with the previously mentioned disk means 29 in accurately placing the fixture in a manner to be described hereinafter. In Figure 3 of the drawings, the five inch spacing of selective disk means mounting cross bore is indicated at 34, and the ten inch spacing of selective bores is indicated at 35.

The bracket 20 includes a base 36 and an L-shaped upstanding wall 37, the portion of said L-shaped wall which is aligned with the previously described support wall 22 as indicated in Figure 2 is provided with an upright slot 38, and said L-shaped wall is reinforced by the strengthening web 39. The base 36 is provided with a bottom face groove 40 in which to receive the positioning rib 17 of the base plate 16, and said base also includes longitudinal slots 41 overlying the base plate bores 18 and through which to receive securing screws 42 selectively threadable into the bores for securing the bracket 20 at selected positions along the base plate.

Bolt means 43 passing through a cross bore 44 in the base portion 6 and through the slot 38 in the bracket 20 serves to adjustably support the fixture on the bracket 20, in cooperation with the previously described bolt means 27.

A support slide 45 having a bottom face groove 46 in which to receive the upstanding rib 17 of the base plate is 'slidable along the base plate and serves as a support for selected Johannsen gage blocks 47, hereinafter termed Jo-blocks, after the practice in the trade. It is to be noted that the top surface of the support slide 45 is disposed on the same horizontal plane as are the top surfaces of the

bracket bases

21 and 36, particularly the former.

It will be readily apparent that the fixture can be arranged as shown in Figure 1 in which the base portion 6 of the base member 5 is horizontally disposed on the base plate 16, and the swing block 8 can be swung about the swing centers 11 to cause the cutting diamond 14 to dress the peripheral surface of the grinding wheel 15 in the manner desired. When it is desired to place the fitting at an angle the bolt means 27 and 43 may be loosened and adjusted in the bracket slots 38, spacing of the

brackets

19 and 20 being suitably varied by utilizing the

selective securing devices

18, 25, 26, 41 and 42. The disk means 29 may be permitted to remain on the base 21 of the bracket 19 and the disk means 33 may be supported on a selected column of Jo-blocks 47 placed upon the slide 45 in the manner indicated in Figure 3 in order accurately to determine the desired angular positioning of the fixture. After the angular positioning has been accurate- 1y determined the bolt means 27, 29 and 43 can be tightdragons ened to securely fix the members 5 and 8 on the

brackets

19 and 20. The angular position illustrated in Figure 3 shows the bottom face of he base portion 6 at a shift or 4 adjustment of 1845, the basic calculation for which is known to every tool maker, but as a rule is taken from established tables drawn up by engineers. Tables will differ from shop to shop, depending on many varying factors and opinions prevailing among technical men as regards the proper tool clearance for the great variety of metals and their alloys, then again allowances are required for soft, half-hard and hard-rolled metals. Therefore, fixed rules or standards cannot be stated, and it remains to utilize the try and test system. The 1845 base angle is indicated at 48 on Figure 3 and attention is also directed to the perpendicular line ab depending from the axis of the grinding wheel 15 on Figure 3. In shop practice, when cutting a clearance radius, concave or convex, onto a grinding wheel, the cutting diamond 14 must be shifted away from the vertical center line of the wheel, as indicated in Figure 1, to an angular position equal to that of the base angle, as indicated by the line ac on Figure 3. 1845 as indicated at 49 on Figure 3.

'The elongated cutting edge of the cutting diamond 14 is employed for cutting clearance radii on grinding wheels for the very important reason that by application of this long cutting edge, all a toolmaker has to do is shift the fixture, as indicated in Figure 3, so that the periphery'of the wheel to be trimmed is tangential exactly in the precise center line of the elongated cutting edge of the diamond,

as illustrated.

A good pair of eyes can most easily observe that, but I a magnifying glass can be helpful to get the tangent contact point exactly right, as then the most accurate results can be obtained.

That the procedure above outlined accomplishes the de- Figure 3 and which corresponds to the angle of the base portion 6 as indicated at 48 on Figure 3 and which was originally set by employment of the sine-bar disks 29 and 33 and the Jo-blocks 47 and slide block 45.

It is to be understood that various angular positioning of the fitting-may be accomplished by interposing selected Jo-block columns between the bracket base 21 and the disk means 29 and between the disk means 33 and the supporting slide block 45, and it is to be understood also that the disk means 33 can be mounted in the base portion bore 44 or in the base bore 30. After proper angular adjustment of the fitting has been at tained in the manner stated, the bolt means 27, 29 and 43 are tightened to fixedly secure the adjustment on the supporting

brackets

19 and 20.

It should be understood that in every setup it is of great importance that all securing screws and bolts be tightened only lightly at first, to make sure that the Joblocks used can be moved easily in and out from under the sine-bar disk means. When the final securing or locking of the adjustment is started, it should be done slowly and gradually over the whole setup. As the tightening is continued, the Jo-blocks should be tried re peatedly to see that they are not squeezed tight. if they are squeezed tight a small wooden mallet can be emand 5 the U-shaped base member 5% and the U-shapcd swing block may be formed as previously described, and

the swing block may be swingably supported at $2. The

diamond carrier 53 and the cutting diamond 54 thereon maybe constructed and mounted in the manner previously described, and the same form of base plate 55 It is to be noted that the angle abc'also is may be provided. The

brackets

56 and 57 may be constructed and mounted in the manner previously described, but it is to be noted that a modified construction and arrangement of sine-bar disk means is employed. In this modified an'angement the base member base portion is provided with a quarter-cylindrical recess 58 at the end extremity thereof supported on the bracket 56,.and in this recess a cylindrical disk means or measuring plug 59 is mounted. This disk means or plug is in the form of an Alnico magnet having an axial bore 60 and a wedgeshaped radial slot 61 opening through the periphery thereof, and is magnetically attracted to and securely held in the base member recess 58.

At the bottom center of the base portion of the base member 50 a similar disk means or measuring plug 62 in the form of .a cylindrical permanent Alnico magnet having an axial bore 63 and a radial slot 64 is magnetically heldin the half-cylindrical recess 65, and this disk means is disposed over the slidably mounted block 66 whereon selected I o-blocks may be mounted in the manner, and for the purposes previously described.

The magnetic sine-bar disk means or measuring plugs 59 and 62 may be pushed out of their receiving recesses 58 and 65 by hand when the radius dresser is to be used for ordinary radial trimming of .a grinding wheel, that is when the dresser is to be put to uses wherein the angular adjustment features are unnecessary. When the angular adjustment features are to be employed, the sinebar disk means or measuring plug 59 will cooperate with the top surface of the base of the bracket 56, and the sine-bar disk means or measuring plug 62 wil cooperate with the slide block66 in the manner previously described.

In the form of the invention illustrated in Figures 6 through 9, the base member base portion 67 has a right angular corner 68 received in a right angular recess formed between right angular walls 69 in a three-fourths cylindrical permanent Alnico magnet disk means or measuring plug 7 ti. This sine-bar disk means or measuring plug is shown in perspective detail in Figure 7 from which it will be apparent that it includes an axial bore 71 at the axis of which the right angularly disposed base portion corner receiving walls intersect. The converging walls .69 have magnetic polarity to hold good and tight to the base portion corner 68 in the manner clearly illustrated in Figure 6. The base member base portion 67 also may carry the bolt means 72 by which vertical adjustment on the cooperating supporting bracket may be aifected.

The base member base portion also is provided with a downwardly opening and centrally disposed half cylindrical recess 73 in which to receive the cylindrical sinebar disk means or measuring plug 74 which is in the form of a permanent Alnico magnet including the threaded axial bore 75. In this magnet form the extreme ends of the disk means or cylindrical plug 74 have polarity and screw means 76 are employed to secure pole pieces 77 to the ends of the member 74 so that the polarity will be transferred to the pole pieces clearly illustrated in Figures 6 and 8. The pole pieces 77 are attracted to and held securely against iron bars '78 secured at 79 at opposite faces of the base portion of the base member 50, and it will be apparent by reference to Figure 8 that the pole pieces are spaced so as to snugly embrace the base portion of the base member 50. Although the disk means or measuring plug 74, being a permanent magnet would cling to the recess 73 itself, in order to assure against slipshod use which might lead to errors in a setup, the provision of the pole pieces 77 and the attraction thereof tothe iron bars 78 are utilized to absolutely assure against an. inadvertent dislocation and misuse.

The manner of use and the advantages of the arrangements illustrated in Figures 4 through 9 will be apparent in light of the foregoing description of the form of the invention illustrated in Figures 1 to 3.

While example disclosures of the structural features of j the invention are made hercin it isgto be understood that variationsin thestructure ,and arrangementof the parts.

may be made without departing from the spirit and scope of the invention as defined in the appended claims.

I claim:

1. In apparatus of the character described, a U-shaped base member comprising a base portion and a pair of upstanding support arms, a U-shaped swing block comprising abase portion and a pair of upstanding mounting arms disposed between said support arms, bearing means swingably supporting the mounting arms on thte support arms, the spacing of the mounting arms providing a central space in which to accommodate projection of a Work piece, a diamond carrier, a cutting diamond on said carrier and projecting into the space between the mounting arms, means supporting said carrier on the swing block base portion, sine-bar disk means mounted on the base member base portion in position for engagement with angle determining gage block means, supporting means I for supporting the U-shaped base member with its base portion horizontally disposed or at an angle to the horizontal, and means for adjustably securing the base member in selected gage block determined positions on said supporting means, said sine-bar disk means and said base member base portion having complementary mounting socket and mounting projection portions and said disk means being magnetically retained on said base member base portion.

2. In apparatus of the character described, a U- shaped basemember comprising a base portion and a pair of upstanding support arms, a U-shaped swing block comprising a base portion and a pair of upstanding mounting arms disposed between said support arms, bearing means swingably supportingthe mounting arms. on the support arms, the spacing of the mounting arms providing a central space in which to accommodate projection of a work piece, a diamond carrier, a cutting diamond on said carrier and projecting into the space between the mounting arms, means supporting said carrier on the swingblock base portion, sine-bar disk means mounted on the base member base portion in position for engagement with angle determining gage block means, supporting means for supporting the U-shaped base member with its base portion horizontally disposed or at an angle to the horizontal, and means for adjustably securing the base member in selected gage block determined positions on said supporting means, said sine-bar disk means and said base member base portion having complementary mounting socket and mounting projection portions and said disk means being magnetically retained on said base member base portion, at least one said disk means comprising a cylindriform magnet, and said base member base portion having a receiving socket in which to accurately receive and retain a peripheral portion of the cylindriform magnet.

3. In apparatus of the character described, a U-shaped base member comprising a base portion and a pair of upstanding support arms, a U-shaped swing block comprising a base portion and a pair of upstanding mounting arms disposed between said support arms, bearing means swingably supporting the mounting arms on the support arms, the spacing of the mounting arms providing a central space in which to accommodate projection of a work piece, a diamond carrier, a cutting diamond on said carrier and projecting into the space between the mounting arms, means supporting said carrier on the swing block base portion, sine-bar disk means mounted on the base member base portion in position for engagement with angle determining gage block means, supporting means for supporting the U-shaped base member with its base portion horizontally disposed or at an angle to the horizontal, and means for 'adjustably securing the base member in selected gage block determined positions on said supporting means, said sine-bar disk means and said base member; portion having, complementary mounting socket assists standing support -arms, a Ushaped swing block comprising a base portion and a pair of upstanding mounting arms disposed between said support arms, bearing means swingably supporting the mounting arms on the support arms, the spacing of the mounting arms providing a central space in which to accommodate projection of a work piece, a diamond carrier, :1 cutting diamond on said carrier and projecting into the space between the mounting arms, means supporting said carrier on the swing block base portion, sine-bar disk means mounted on the base member base portion in position for engagement with angle determining gage block means, supporting means for supporting the U-shaped base member with its base portion horizontally disposed or at an angle to the horizontal, and means for adjustably securing the base member in selected gage block determined positions on said supporting means, said sine-bar disk means and said base member base portion having complementary mounting socket and mounting projection portions and said disk means being magnetically retained on said base member base portion, at least one said disk means comprising a cylindriform magnet, and said base member base portion having a receiving socket in which to accurately receive and retain a peripheral portion of the cylindriform magnet, said magnet having a pole piece extending upwardly from each end'thereof so that the pole pieces are spaced to snugly embrace the base portion of the base member, and iron bars on said base member overlying the pole pieces and to which the pole pieces are magnetically attracted.

5. In apparatus of the character described, a U-shaped base member comprising a base portion and a pair of upstanding support arms, a U-shaped swing block comprising a base portion and a pair of upstanding mounting arms disposed between said support arms, bearing means swingably supporting the mounting arms on the support arms, the spacing of the mounting arms providing a central space in which to accommodate projection of a work piece, a diamond carrier, a cutting diamond on said carrier and projecting into the space between the mounting arms, means supporting said carrier on the swing block base portion, sine-bar disk means mounted on the base member base portion in position for engagement with angle determining gage block means, supporting means for supporting the U-shaped base member with its base portion horizontally disposed or at an angle to the horizontal, and means for adjustably securing the base member in selected gage block determined positions on said supporting means, said means for securing the base member in selected gage block determined positions comprising a base plate, upstanding brackets secured in spaced relation on the base plate, and means for securing end portions of the base member base portion at varied selected heights on said brackets.

6 In apparatus of the character described, a U-shaped base member comprising a base portion and a pair of upstanding support arms, a U-shaped swing block com prising a base portion and a pair of upstanding mounting arms disposed between said support arms, bearing means swingably supporting the mounting arms on the support arms, the spacing of the mounting arms providing a central space in which to accommodate projection of a work piece, a diamond carrier, a cutting diamond on said carrier and projecting into the space between the mounting arms, means supporting said carrier on the swing block baseportion,v sine-bardisk means mounted on the base member base portion in position for portion horizontally disposed or at an angle to the horizontal, and means for adjustably securing the base member in selected gage block determined positions on said supporting means, said means for securing the base member in selected gage block determined positions comprising a base plate, upstanding brackets secured in spaced relation on the base plate, means for securing the brackets on the base plate in varied selected spaced relations, and

means for securing end portions of the base member base portion at varied selected heights on said brackets.

7. In apparatus of the character described, a U-shaped base'member comprising a base portion and a pair ofbase portion, sine-bar disk means mounted on the base member base portion in position for engagement with angle determining gage block means, supporting means for supporting the U-shaped base member with its base portion horizontally disposed or at an angle to the hori zontal, and means for adjustably securing the base member in selected gage block determined positions on said supporting means, said means for securing the base member in selected gage block determined positions comprising a base plate, upstanding brackets secured in spaced relation on the base plate, means for securing the brackets on the base plate in varied selected spaced relations, said brackets and base plate having complementary rib and groove positioning means, and means for securing end portions of the base member base portion at varied selected heights on said brackets.

8. In apparatus of the character described, a U-shaped base member comprising a base portion and a pair of upstanding support arms, a U-shaped swing block comprising a base portion and a pair of upstanding mounting arms disposed, between said support arms, bearing means swingably supporting the mounting arms on the support arms, the spacing of the mounting arms providing a central space in which to accommodate projection of a .work piece, a diamond carrier, a cutting diamond on said carrier and projecting into the space between the mounting arms, means supporting said carrier on the swing block 5 base portion, sine-bar disk means mounted on the base 1 member base portion in position for engagement with angle determining gage block means, supporting means for supporting the U-shaped base member with its base portion horizontally disposed or at an angle to the horizontal, and

means for adjustably securing the base member in selected gage block determined positions on said supporting means, said means for securing the base member in selected gage block determined positions comprising a base plate, upstanding brackets secured in spaced relation on the.

base plate, means for securing the brackets on the base plate in varied selected spaced relations, and means for 1 securing end portions of the base member base portion at varied selected heights on said brackets, and there being included also a support plate slidably along the base plate and whereon to receive gage blocks.

9. In apparatus of the character described, a U-shaped base member comprising a base portion and a pair of upstanding support arms, a U-shaped swing block comprising a base portion and a pair of upstanding mounting arms disposed between said support arms, bearing means swingably supporting the mounting arms on the support 1 arms, the spacing of the mounting arms providing a-cen- ,tral spacein which to accommodate projection of a work engagement with angle determining gage block means, supporting means for supporting the U-shaped base member with its base piece, a diamond carrier, a cutting diamond on said carrier and projecting into the space between the mounting arms, means supporting said carrier on the swing block base portion, sine-bar disk mounted on the base member base portion in position for engagement with angle determining gage block means, supporting means for supporting the U-shaped base member with its base portion horizontally disposed or at an angle to the horizontal, and means for adjustably securing the base member in selected gage block determined positions on said supporting means, said means for securing the base member in selected gage block determined positions comprising a base plate, upstanding brackets secured in spaced relation on the base plate, means for securing the brackets on the base plate in varied selected spaced relations, and means for securing end portions of the base member base portion at varied selected heights on said brackets, and there being included also a support plate slidably along the base plate and whereon to receive gage blocks, said brackets and base plate and said base plate and said support plate having complementary rib and groove positioning means.

10. In apparatus of the character described, a U-shaped base member comprising a base portion and a pair of upstanding support arms, a U-shaped swing block comprising a base portion and a pair of upstanding mounting arms disposed between said support arms, bearing means swingably supporting the mounting arms on the support arms, the spacing of the mounting arms providing a central space in which to accommodate projection of a work piece, a diamond carrier, a cutting diamond on said carrier and projecting into the space between the mounting arms, means supporting said carrier on the swing block base portion, sine-bar disk means mounted on the base member base portion in position for engagement with angle determining gage block means, supporting means for supporting the U-shaped base member with its base portion horizontally disposed or at an angle to the horizontal, and means for adjustably securing the base member in selected gage block determined positions on said supporting means, said means for securing the base member in selected gage block determined positions comprising a base plate, upstanding brackets secured in spaced relation on the base plate, each said bracket having an upright slot therein, and bolt means passing through the base member base portion and said slots for adjustably securing said base member on said brackets.

11. In apparatus of the character described, a U-shaped base member comprising a base portion and a pair of upstanding support arms, a U-shaped swing block comprising a base portion and a pair of upstanding mounting arms disposed between said support arms, bearing means swingably supporting the mounting arms on the support arms, the spacing of the mounting arms providing a central space in which to accommodate projection of a work piece, a diamond carrier, a cutting diamond on said carrier and projecting into the space between the mounting arms, means supporting said carrier on the swing block base portion, sine-bar disk means mounted on the base member base portion in position for engagement with angle determining gage block means, supporting means for supporting the U-shaped base member with its base portion horizontally disposed or at an angle to the horizontal, and means for adjustably securing the base member in selected gage block determined positions on said supporting means, said means for securing the base memher in selected gage block determined positions comprising a base plate, upstanding brackets secured in spaced relation on the base plate, each said bracket having a base equipped with longitudinal slots, and said base plate having a plurality of selective threaded bores extending in spaced relation therealong beneath the bracket base slots, and screw means extending through the bracket base slots and threaded into selected base plate bores for securing the brackets on the base plate in varied selected spaced relations.

References Cited in the file of this patent UNITED STATES PATENTS 431,525 Mattison July 1, 1890 1,826,219 Parker Oct. 6, 1931 2,327,272 Jones Aug. 17, 1943 2,404,148 Thompson July 16, 1946 2,417,150 Berry Mar. 11, 1947 2,425,453 Bavosi Aug. 12, 1947 2,523,680 Christie Sept. 26, 1950 2,602,439 Muench July 8, 1952