Attachment for a grinding machine to grind a predetermined shape into a woodworking tool
United States Patent Gilley 1 1 Apr. 8, 1975 1 1 ATTACHMENT FOR A GRINDING 2.293.100 11/1942 Baumgold 51/100 P MACHINE T0 GRND A PREDETERMINED 2.633.676 4/1953 .leffies et a1. 51/100 R 2.751119 6/1956 Reichel 51/100 F SHAPE INTO A WOODWORKING TOOL [76] Inventor: Clyde l-l. Gilley, Route No. 4, Box  
 375. Martinsville. Va. 24112 [22] Filed: Mar. 4, 1974 [21] Appl. No.: 447,891  
 [52] U.S. Cl. 51/241 R; 51/100 R [51] Int. Cl B24b 9/00 [58] Field of Search 51/100 R, 100 P, 241 R [56] References Cited UNITED STATES PATENTS 548.298 10/1895 Darling 51/100 R 1.119.022 12/1914 Lewis Sl/lOOR 1.318.441 10/1919 Fowler .1 51/101) R Primary Examiner-Al Lawrence Smith Assistant ExzuninerMarc R. Davidson Attorney, Agent, or Firm-Shoemaker and Mattare [57] ABSTRACT An attachment for a grinding machine to grind a woodworking tool to a predetermined shape includes a movable holder for the wood working tool and a fixed holder for a template having the desired shape. said movable holder including a pin engageable with the template and movable relative thereto to thus cause corresponding movement of the woodworking tool relative to a grinding wheel to grind the desired shape into the wood working tool.  
 12 Claims, 16 Drawing Figures PATENTEDAPR&#39; 8&amp;975  
 SiiiET 3 BF 9 LBYSJOS PHENTEUAPR 81975 SiiIU 6 [If 9 FIG/O.  
 ATTACHMENT FOR A GRINDING MACHINE TO GRIND A PREDETERMINED SHAPE INTO A WOODWORKING TOOL BACKGROUND OF THE INVENTION This invention relates to an attachment for a grinding machine to grind a tool to a predetermined shape to cut a desired shape into a piece of wood.  
  The process of making a woodworking tool, such as a knife or the like, to cut a given shape in a piece of wood involves two basic steps: making a template; and grinding the knife. However, since the angle at which the knife strikes the wood varies as the depth of cut changes, the exact shape desired to be cut into the wood cannot be ground into the knife. Accordingly, such factors as the depth of the cut to be made and the angular relationships of the knife relative to the wood during the cutting process must be taken into account in designing the template for use in grinding the knife. Therefore, the knife is ground with a deeper contour than that of the template or the piece of wood, so that the desired shape can be cut into the wood, even though the knife is disposed at an angular relationship relative to the wood.  
  Because of the angular relationships between the knife and the piece of wood in the prior art a template had to be designed by hand so that the machine would grind the knife to cut the desired shape in the wood, and neither the template nor the knife had the same shape as the desired shape of the wood. This process was both time consuming and costly, and due to the larte number of calculations and measurements required, human error frequently resulted, with consequent waste in the templates and knives. Moreover, even with such prior art methods, operators frequently resorted to trial and error methods in order to grind a knife to cut a desired shape in a piece of wood.  
  In accordance with the present invention, a uique attachment is provided which can be readily assembled to a machine, such as a universal head grinder or the like, and a template is made with the exact shape, except in reverse, desired to be cut into the wood. The template is then secured to a template holder portion of the attachment in a position relative to the grinding wheel of the machine corresponding to the position of a knife relative to a piece of wood when the long point of the knife is at its peak of cut during the process of cutting the wood. The knfe to be ground is also secured to a knife holder portion of the attachment in parallel relationship to the bed of the machine, and the attachment includes a pin engageable with the template and movable relative thereto and connected with the knife holder to move the knife holder and knife relative to the grinding wheel to grind the knife to the desired shape. The angular relationship of the template and pin relative to the knife results in the knife actually moving a greater distance than the actual depth of cut to be made in the wood and the knife is accordingly ground deeper than the actual depth of the template, which the guide pin follows. Accordingly, the knife is automatically ground to the desired shape to compensate for the difference in angle of the knife relative to the piece of wood as the depth of cut changes, and the exact shape to be formed is therefore easily obtained without requiring time consuming and complicated hand design methods.  
  Therefore, with the present invention, the template is simply made to the exact shape as the desired shape to be cut into the piece of wood, and the attachment automatically compensates for the necessary change in the depth of the shape to be ground into the knife, thereby eliminating all trial and error methods or tedious or time consuming designs and calculations necessary in the prior art to grind a knife to the desired shape. The attachment of the present invention can be used on most universal head grinders and can be attached by two bolts, and converts the head grinder into a profile grinder where wood cutting tools, such as moulder, shaper and tenon machine coping head knives, can be ground to cut a predetermined shape into a piece of wood.  
  Basically, in the present invention the template is supported on the grinding machine in a position relative to the grinding wheel corresponding exactly to the position a knife will have relative to a piece of wood to be cut by the knife. Therefore, ths shape ground into the knife is somewhat deeper than the template itself and results in the exact shape desired to be cut into the wood.  
 OBJECTS OF THE INVENTION It is an object of this invention to provide an attachment for a grinding machine for grinding a woodworking tool, such as a knife or the like, to cut a desired shape into a piece of wood, and wherein the attachment includes means for positioning the knife relative to the grinding machine such that a desired shape is cut into the knife to compensate for variations in the angle between the knife and the piece of wood as the depth of cut of the knife in the wood changes during successive revolutions of the knife relative to the piece of wood.  
  Another object of the invention is to provide an attachment for a grinding machine for grinding a knife or similar tool to cut a desired shape into a piece of wood, and wherein the attachment includes means for automatically mechanically grinding the knife to the desired shape without requiring complicated and time consuming calculations and trial and error methods to arrive at the desired shape to be ground into the knife in order to obtain the proper shape of the wood cut thereby.  
 BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top perspective view of the attachment according to the invention shown in position on a grinding machine.  
  FIG. 2 is a top perspective view from a different angle of the attachment of the present invention in position on a grinding machine.  
  FIG. 3 is a side view in elevation of the attachment of FIGS. 1 and 2.  
  FIG. 4 is a view in section taken along line 4-4 in FIG. 3.  
  FIG. 5 is a view in section taken along line 5-5 in FIG. 4.  
  FIG. 6 is a vertical sectional view taken along line 6-6 in FIG. 4.  
  FIG. 7 is a view in section taken along line 7-7 in FIG. 3.  
  FIG. 8 is a schematic view of a knife secured in a head or shaper collar and illustrates how the angle between the knife and the piece of wood changes as the depth of cut changes.  
  FIG. 9 is a plan view of a template engaged with a piece of wood and showing how the template is made to the exact shape of the piece of wood.  
  FIG. 10 is a fragmentary view illustrating the relief angle of the knife.  
  FIG. II is a diagrammatic view illustrating a knife having a portion of a desired shape ground thereinto on the left and a template having a plurality of shapes on each of the four sides thereof to be ground into a knife and thus cut into a piece of wood.  
  FIG. 12 is an exploded, perspective view ofa portion of the attachment of the invention and illustrating particularly the knife holder and guide bar and guide pin connected therewith.  
  FIG. 13 is an enlarged view in section taken along line 13-13 in FIG. 6.  
  FIG. 14 is an enlarged, exploded, perspective view of the template holder portion of the attachment of the invention.  
  FIG. 15 is a schematic view of the different adjustments made with the machine and showing the different amounts of movement of the parts thereof which result in the knife being ground to the desired shape.  
  FIG. 16 is an enlarged sectional view through the template clamp bar of the template holder, showing the manner in which the clamp bar may be adjusted trans versely for centering the template relative to the knife held in the knife holder of the attachment.  
 DETAILED DESCRIPTION OF THE INVENTION In the drawings, wherein like reference numerals indicate like parts throughout the several views, the at tachment is indicated generally at A and includes a substantially flat, rectangular base B having a substantially flat, smooth bottom surface 10 and a substantially flat, smooth upper surface 11. A vertically upstanding flange 12 is integral with one side edge of the base B and projects upwardly above the upper surface 11 thereof and has an opening I3 therethrough, substantially medially thereof. A pair of laterally outwardly projecting ears or flanges 14 and 15 are on the opposite ends of the base B and the bottom surfaces of the ears or flanges are substantially flush or planar with the bottom surface 10 of the base B. The ears l4 and 15 have slots or notches l6 and 17, respectively, therein, and the base B and attachment A may be readily removably secured to the bed of a machine M, which has a T- shaped slot 5 in the uppper surface thereof, and in which the head 18 of a bolt 19 is received, the bolt 19 extending upwardly from the slot S above the bed of the machine M and through the slots 16 and 17 and the ears I4 and I5, and having a washer 20 and nut 21 threaded thereon to securely clamp the base B to the machine M.  
  A workholder WI-I is attached to the base B and includes means for securely holding a knife K or other suitable woodworking tool and for moving the knife relative to a grinding wheel or stone G for grinding the desired shape into the knife K. The workholder WH includes a floating bed F comprised of a flat, rectangularly shaped base plate 22 secured to the upper surface II of the base B by means ofa plurality of screws or the like 23 extended through the base plate and into openings or holes 24 in the top surface 11 of base B. The base plate 22 has a pair of elongate, spaced apart, parallel, V-shaped channels or ball races 25 and 26 in the upper surface thereof adjacent opposite ends of the base plate and extending completely across the width thereof. The floating bed F also includes a longitudinally movable middle plate 27, having a pair of spaced apart, parallel, V-shaped channels or ball races 28 and 29 in the bottom surface thereof in registry with the ball races in the base plate 22, and a plurality of balls 30 are disposed in the races for movably supporting the middle plate 27 spaced from the base plate 22 and parallel thereto.  
  An elongate, flat, rectangular ball position and retainer 31 is provided for each row of balls 30 and has a plurality of spaced openings 32 therethrough through which the balls 30 project for rolling engagement in the respective confronting races in the base plate 22 and middle plate 27. The balls are retained in the races by means of pegs or pins 33 in the opposite ends of the races. The upper surface of the middle plate 27 also has a pair of spaced apart, elongate, parallel, V-shaped ball races 34 and 35 therein extending transversely to the plane of the grinding wheel G and perpendicularly to the ball races 28 and 29. An upper or floating plate 36 has a pair of elongate, V-shaped ball races 37 and 38 therein in opposed aligned relationship with the races 34 and 35 and a plurality of balls 39 are disposed in the races maintaining the upper or floating plate 36 spaced above the middle plate 27. The balls are retained in position in the races by means of pegs 40 at the opposite ends of the races and by elongate, flat, rectangular ball position and retainers 41, having openings 42 therethrough through which the balls 39 extend.  
  The top surface of the upper or floating plate 36 has a hole 44 substantially in the center thereof and a cylindrical pivot pin 43 is fitted at one end thereof in the hole and extends above the upper surface of the top plate 36. A rectangular mounting plate 45 is disposed in overlying engagement with the top surface of upper plate 36 and has a centrally located hole 46 therein in which the upper end of the pivot pin 43 is received, so that the mounting plate 45 is pivotally adjustable in the plane of the plate.  
  An adjusting block 47 is secured to the upper surface of plate 36 adjacent the back edge of mounting plate 45 by means of a pair of screws or the like 48 and 49 extended through the block into the upper surface of the plate 36. A substantially horizontally disposed ad justrnent screw 50 is threaded through the block and into engagement with the back edge of plate 45 for making minor pivotal adjustments of the plate 45 about pivot pin 43 to align the plate 45 relative to the plane of the grinding wheel G.  
  A pair of clamping plates 51 and 52 are disposed adjacent the back edge and one side edge, respectively, of the plate 45 and clamp screws 53 and 54 extend downwardly through the clamping plates 51 and 52 and into the upper surface of the plate 36 for drawing the clamping plates 51 and 52 downwardly against the upper surface of plate 45 to securely hold it in adjusted position. In FIGS. 1, 2, 3 and 4 one of the clamping plates comprises a washer 52&#39;, whereas in the remaining figures, a modified, L-shaped plate is shown.  
  A mounting block 55 is attached to the upper surface of plate 45 by means of a plurality of screws or the like 56 extended upwardly through the plate 45 and into the bottom of block 55. The front edge of block 55 or the edge 57 thereof facing the grinding wheel G is contoured to conform generally to the periphery of the grinding wheel G to provide clearance for the wheel as a knife is ground in the machine. A pair of spacer bars or blocks 58 and 59 are attached to the upper surface of the mounting block in parallel, spaced apart relationship to define a channel 60 therebetween and a knife holding block or plate 61 is secured on top of the spacer bars or blocks 58 and 59 and has a pair of upstanding flanges 62 and 63 thereon, and a substantially flat, planar, smooth upper surface 64 on which the knife K is supported while it is being ground.  
  A knife clamping plate 65 has downturned flanges or legs 66 and 67 at its opposite ends, and the dimensions of the clamping plate 65 are such that one flange 66 is disposed between the upstanding flanges 62 and 63 of the plate 61 and the other flange 67 is disposed adjacent the end of plate 61 nearest the grinding wheel G.  
  An inverted, channel-shaped pressure plate 68 has downturned flanges 69 and 70 along its opposite edges and the plate 68 is dimensioned such that flange 69 engages the upper surface of clamping plate 65 spaced slightly inwardly from flange 66 of plate 65 and the flange 70 thereof engages the upper surface of plate 65 substantially medially of the plate 65.  
  A pair of clamping screws or bolts or the like 71 and 72 are extended through openings 73 and 74 in the pressure plate 68 and through openings 75 in clamping plate 65, openings 76 in plate 61, openings 77 in the spacer bars 58 and 59, and into threaded openings 78 in the upper surface of mounting block 55.  
  An alignment plate or fence 79 for the knife K has a pair of slots 80 and 81 in a lower edge portion thereof and a pair of screws or bolts or the like 82 and 83 are extended through the respective slots and into a pair of threaded openings in the side of spacer bar 59 for se curing the fence to the workholder and the upper edge of the fence extends above the upper surface 64 of plate 61, so that when in use, one side edge of the knife K is engaged against the fence to accurately position the knife in the workholder. A threaded adjustment screw 84 is also extended into a threaded opening in the upstanding flange 63 of plate 61 and the head of the screw extends over the surface 64 toward the knife K and the rearward edge of the knife K is abutted against the adjustment screw 84 to accurately position the knife axially in the workholder. An additional screw 85 is extended through an enlarged opening 86 in the plate 61 and downwardly through an opening 87 in the spacer bar 59 and then to a threaded opening 88 in the upper surface of mounting block 55 to securely retain the spacer blocks in position on the mounting block. A set screw 89 is also threaded downwardly through a threaded opening 90 in the flange 62 of plate 61 and into the channel 60 between the spacer blocks 58 and 59 for a purpose to be hereinafter described.  
  In order to manipulate the mounting block 55 and a knife K clamped therein, a pair of laterally outwardly extending wings or plates 91 and 92 are provided, and the plates 91 and 92 have upturned flanges 93 and 94, respectively, at their inner edges and suitable fastening means, such as screws or bolts or the like 95, are extended through the upturned flanges into the opposite end portions of the plate 36. Suitable handles or knobs or other grasping means 96 and 97 are suitably affixed to the plates 91 and 92 adjacent the outer ends thereof, so that the knobs or handles 96 and 97 may be grasped in the hands of an operator and the workholder readily manipulated toward and away from the grinding wheel and laterally or diagonally, as desired.  
  A suitable dust shield 98, such as a piece of asbestos or other suitable material, is secured to the edges of plates 91 and 92 closest to the grinding wheel 0, and the shield extends or hangs downwardly between the grinding wheel and the floating bed F to thus prevent dust and the like from interfering with operation of the balls 30 and 39.  
  A control bar assembly 99 is also carried by the workholder WH, and includes a first, elongate guide bar or control bar 100, having one end thereof extended into the space 60 between spacer bars 58 and 59 and adjustably clamped therein by means of set screw 89. The outer end of the guide bar 100 is pivotally connected to a U-shaped bracket 101 between the opposite side walls 102 and 103 of the bracket by means of a pivot pin 104 extended through aligned openings 105 and 106 in the side walls and through an opening 107 in said other end of the guide bar 100. The guide bar 100 is maintained in a predetermined, angularly adjusted position relative to the bracket 10] by means of a slotted link 108, which is pivotally connected at one end thereof to the guide bar 100 adjacent its said other end by means of a screw 109 or the like extended through said one end of the link and into the side of the guide bar and a threaded stud 110 which is extended through the slot of the slotted link 108 and on which a clamping screw or cap 111 is threaded into clamping engagement with the side of link 108 to thus maintain the guide bar 100 in an angularly adjusted position relative to the bracket 101. The bracket 101 also includes a dividing wall 112 extending between the side walls 102 and 103 and an upstanding top wall or cross member 113 defining with the dividing wall 112 a channel or space 114, in which a further or second guide bar is slidably positioned. The guide bar 115 may be adjustably clamped in a predetermined, axially adjusted position in the channel 114 of bracket 101 by means of a threaded set screw 116, which is threaded downwardly through the top wall 113 into engagement with the upper surface of the second guide bar 115 to clamp the guide bar 115 against the dividing wall 112. Also, an elongate guide pin 117 is adjustably positioned through an opening 118 in an outer end portion of the second guide bar 115 and the pin 117 may be retained in adjusted position in the opening 118 by means of a set screw 118&#39;threaded into engagement therewith. The pin 117 is disposed at a right angle to the axis of the second guide bar 115. Accordingly, with the arrangement above described, the angular adjustment between the first and second guide bars 100 and 115 may be readily changed and secured in different adjusted positions simply by loosening the nut 111 and adjusting the guide bars about pivot pin 104 and then retightening the cap or nut 111. Moreover, the length of the second guide bar 115 extending downwardly from bracket 101 may be readily adjusted by loosening set screw 116 and sliding the guide bar to a desired adjusted position and then retightening the set screw 116.  
  A template holder TH is also attached to the base B of the attachment A and includes a generally U-shaped mounting plate or bracket 119, having a substantially horizontal portion or bight portion 120 and upstanding legs 121 and 122 at the opposite ends thereof. The bracket 119 is secured to the base by means of a screw 123 extended through the opening 13 in flange 12 on the base B and through an opening 124 adjacent the top edge of the bight portion 120 of bracket 119, said bracket being securely clamped against flange 12 by means of nuts 125 threaded onto screw 123 and adjusted tightly against the horizontal portion 120 of the bracket.  
  A template holder subframe assembly 126 is secured to the bracket 119 and comprises a substantially U- shaped, horizontally disposed bottom frame member 127 and a pair of generally L-shaped side frame members 128 and 129 secured to the opposite ends or sides of the bottom frame member 127 by means of a plurality of screws or the like 130 extended upwardly through the bottom frame member 127 and into the horizontal leg portions of side frame members 128 and 129. The subframe assembly 126 is secured to the bracket 119 by means of a plurality of screws or the like 131 extended through openings 132 in the vertical leg portions 121 and 122 of the bracket 119 and into threaded openings 133 in the facing vertical edge portions of the opposite end frame members 128 and 129.  
  A pivotal top frame assembly 134 is pivotally attached to the subframe assembly 126 and includes an inverted, U-shaped frame or bracket member 135 and a pair of side block members 136 and 137 suitably secured at one of their ends to the opposite ends or legs of the Ushaped frame member 135. A pair of downwardly extending, pivot blocks or mounting blocks 138 and 139 are on the under side of the blocks 136 and 137 at their other ends, and the pivot blocks 138 and 139 are pivotally attached to the upper ends of side frame members 128 and 129 at the inner surfaces thereof by means of a pair of screws or bolts or the like 140 and 141 extended through openings 142 and 143, respectively, in the upper ends of side frame members 128 and 129 and into threaded openings 144 and 145, respectively, in the pivot blocks 138 and 139. The frame assembly 134 is maintained in different angularly adjusted positions relative to the subframe assembly 126 by means of a pair of slotted links 146 and 147 at the opposite sides of the frame assembly, with said links pivotally secured at their upper ends to a pair of blocks 148 and 149 on the underside of the side frame blocks 136 and 137 by means of screws or the like 150, extended through openings 151 in the upper ends of the links 146 and 147 and into threaded openings 152 in the blocks 148 and 149, and the links are secured in adjusted position by means of screws 153 and 154 extended through the slots of the respective links and through aligned openings 155 and 156 in the side frame members 128 and 129, and having clamping nuts or caps 157 and 158 threaded thereonto at the outer surfaces of side frame members 128 and 129.  
  A suitable scale 159 is secured to the outer surface of side frame member 128 by means of a pair of screws 160 extended through openings 16] at one edge of the scale 159 and into threaded openings 162 in the side frame member 128.  
  A suitable pointer 163 is attached to the side block 136 of the frame assembly 134 by means of a screw 164 or the like, and the pointer extends downwardly to adjacent the calibrated scale 159, to thus indicate the an gular adjustment between the frame assemblies 126 and 134.  
  Further, the upper surfaces of the side frame or block members 136 and 137 are formed with dovetail channels 165 and 166 therein, respectively.  
  A template clamping assembly 167 is adjustably attached to the angularly adjustable frame assembly 134 and comprises a rectangularly shaped plate 168 having a dovetail shaped block 169 and 170 secured to the underside thereof adjacent the opposite ends thereof, said dovetail blocks 169 and 170 received in the dovetail channels 165 and 166 in the side frame or block members 136 and 137, to thus enable the assembly 167 to be adjusted transversely of the template holder assembly TH. In order to make the adjustments of the tem plate clamping assembly 167 relative to the frame assembly, a pair of arcuately shaped keepers or retainers 171 and 172 are secured by means of screws or the like 173 to the outer side portion of side block member 136 in downwardly extending relationship therefrom, and the keepers 171 and 172 have oppositely directed slots 174 and 175 therein, respectively, which when the keepers are assembled together to the frame member, define a circular opening extended through the retainers 171 and 172 at the inner ends of the respective slots.  
  An adjustment block 176 is secured to the template clamping assembly 167 by means of a pair of screws or the like 177 extended through the adjustment block 176 and into the adjacent end of the dovetail block 169, or the screws or the like could be extended into the end of the plate 168, if desired, and a threaded adjustment screw 178 is threadably extended through a threaded opening 179 adjacent the lower end of block 176, and the screw 178 has a channel or recessed portion 180 therein adjacent its inner end, with said channel 180 disposed through the slots 174 and 175, and thus held against axial movement when the screw is turned. Accordingly, when the screw is threaded in or out of the threaded opening 179, it causes movement of the block 176 and thus the template assembly 167 transversely of the frame assembly 134.  
  An elongate, rectangularly shaped stop plate or fence 181 is secured to the upper surface of plate 168 along one edge thereof by means of a pair of screws 182 extended through slots 183 and 184 at the opposite ends of the fence 181 and into threaded openings 186 and 187 in the plate 168 adjacent its opposite ends, and a template T to be clamped in the template clamping as sembly 167 is disposed with one edge thereof abutted against an edge of the fence 181 to thus accurately position the template relative to the template holder assembly TH.  
  A pair of suitable, conventional over-center type template clamping devices 188 and 189 are secured to the upper surface of the plate 168 at its opposite ends, and each of the clamping devices 188 and 189 includes a plurality of adjustable feet or clamping members 190, having resilient template engaging portions or feet 191 at the lower ends thereof, and said clamping members being adjustable toward and away from the plate 168 by means of threaded adjustment through the lock nuts 192 and 193 threaded onto the members 190 on opposite sides of the levers 194 of the clamping devices, said levers being manipulated pivotally toward and away from a template by means of outwardly extending handles 195 and 196 pivotally connected to the levers 194.  
  In operation, the shape of a cut to be made in a piece of wood W is selected, as seen in FIG. 9, and the depth of cut D to be made is ascertained, and a template T is made having the necessary shape therein required to cut the exact shape into the piece of wood. A drawing is then made, as in FIG. 8, showing the shaper collar SC mounted on a spindle S, and having a pair of knives K attached thereto. A piece of wood W is then sketched adjacent the shaper collar SC and a line L1 is drawn from the center of the spindle outwardly past the point of one of the knives K and perpendicularly through the wood W. A point X is then marked on the line L1 a distance away from the shaper collar SC corresponding to the maximum depth of cut D to be made in the wood. A second line L2 is then drawn through the point X and to the point or portion of the shaper collar SC in which a knife would be positioned, as indicated in phantom line, for the maximum depth of cut. The angle a between lines L1 and L2 is then measured and this is the angle set with the pointer 163 and scale 159 on the template holder portion TH of the attachment A.  
  Accordingly. the template clamped in the template holder attachment is disposed at the same angle relative to the grinding wheel G or the plane of the bed of the machine M that the knife K will be disposed relative to the piece of wood W at its maximum depth of cut, and the desired contour will thereby be cut into the knife.  
  Also, the grinding wheel G may be adjusted up or down relative to the knife K in order to provide the proper relief angle [3, as seen in FIG. when the knife is at its maximum depth of cut.  
  In FIG. 15, the movement of the workholder and knife to the right toward the grinding wheel is shown in full lines and in phantom lines, respectively. As seen, the distance P that the knife moves is greater than the depth R of the template from the angular relationship of the knife, guide bar and guide pin and template. In H6. 11, a template having different designs therein is shown, and as illustrated, a template may have a different pattern in each of its four edges, whereby a single template plate may be used in the attachment for grinding four different shapes of knives. At the left in FIG. 11, a knife K with one of the desired profiles of the template ground therein is illustrated, and as can be seen, the contour in the knife is deeper than the contour in the template.  
  Once the desired shape and depth of cut and angles have been determined, as above described, and a template has been made, the attachment A is quickly and easily attached to the grinding machine M simply by attaching the base B to the bed of the machine M by means of the bolts 19 received in the slot S of the machine M and extended upwardly through the slots 16 and 17 in the ears or flanges 14 and on opposite sides of the base and tightening the nuts 21 against the upper surface of the ears 14 and 15. The bolts 71 and 72 are loosened and a knife K to be ground is positioned beneath the downturned flange 67 of plate 65 and on top of the surface 64 of plate 61, and the bolts 71 and 72 readjusted or retightened to securely clamp the knife K in position, with one side edge of the knife K disposed against the fence 79 and the back edge thereof disposed against the adjusting screw 84, which may be adjusted before the knife is securely clamped in position, if any such adjustments are necessary. The fastening or clamping screws or caps 157 and 158 of the template holder assembly TH are then loosened and the upper frame assembly 134 and template clamping assembly 167 are angularly adjusted relative to the subframe assembly 126 until the pointer 163 is at the desired angle on the calibrated scale 159 carried by the lower or subframe assembly 126. The caps or screws 157 and 158 are then tightened and the angular rela tionship between guide bars 115 and is adjusted, with the axis of guide bar being disposed parallel to the plane of plate 168 of the template clamping assembly 167, and the clamping screw or cap 11] is tightened to securely maintain the guide bars 100 and 115 in the angularly adjusted relationship.  
  A template T is then placed in the template clamping assembly 167, with one edge of the template disposed against the fence or stop 181 and the handles 195 and 196 are manipulated to urge the clamping members downwardly against the template to securely clamp it in position. The adjustment screw 178 is then turned to cause the plate 168 and template clamping assembly 167 to be adjusted transversely to align the center of the template with the center of the knife K held in the workholder portion WH of the attachment A.  
  The axial position of guide bar 100 in the mounting block 55 is adjusted by loosening and retightening the set screw 89 and the axial position of guide bar 115 in the bracket 101 is adjusted by loosening and retightening the set screw 116, so that the pin 117 secured to the guide bar 115 will be disposed at the shallowest part of the template T. If necessary, the pin 117 may be adjusted upwardly or downwardly relative to the template by loosening and retightening the set screw 119.  
  Further, if slight horizontal alignments of the workholder portion of the attachment are necessary, the screws 53 and 54 are loosened, releasing the clamps 51 and 52 from the upper surface of plate 45, and the adjustment screw 50 is threaded in or out of block 47 and against the back edge portion of plate 45 to pivot the plate about pivot pin 43 and thus make any necessary horizontal adjustments of the plate 45 and the mounting block 55, after which the screws 53 and 54 are retightened, securely clamping the plate 45 in position on the upper surface of plate 36.  
  The vertical position of the grinding wheel G relative to the knife K held in the workholder portion WH of the attachment is then adjusted to obtain the desired relief angle, and the machine is started and the operator grasps the handles or knobs 96 and 97, and by manipulating the knobs and the movable portions of the workholder portion WH, causes the pin 117 to follow the contour of the template, and this movement is imparted to the mounting block 55 and the knife K, causing the knife K to move in a corresponding but proportional manner with regard to the grinding wheel G, it being obvious from the disclosure set forth hereinabove that the amount of travel of the knife K toward and away from the grinding wheel G is greater than the ac tual depth of cut, due to the angular relationship of the pin 117 relative to the plane of the knife, so that as the pin 117 moves horizontally toward the grinding wheel G and into the deepest parts of the contour of the template T, the point of engagement between the pin 117 and template T moves upwardly on the pin 117, and thus resulting in the greater distance of travel of the knife K.  
  The floating bed F, with the perpendicularly disposed sets of balls and races, enables the mounting block 55 and knife K to be moved substantially universally in the plane of the knife K for grinding the desired shape into the knife.  
  The pin 117 should have the same cross sectional thickness as the thickness of the grinding wheel G, and for square corners or very small contours, the pin should have a square cross sectional shape, rather than a round cross sectional shape, and if the grinding edge of the grinding wheel G is rounded, then the pin should be rounded, and conversely if the grinding edge of the grinding wheel G is squared, then the pin should also have a square cross sectional shape.  
  Thus, with the present invention, only one setting must be made to the attachment in order to grind a knife to the desired shape, and that setting comprises the angular adjustment between the pointer 163 and calibrated scale 159, which setting is determined from the drawing as described above, and human error is, therefore, negligible and very little skill is required in setting up the machine to grind a knife. The remaining adjustments to the attachment as described above are merely minor adjustments, which may be necessary in order to properly align the elements of the attachment relative to the machine for grinding the knife. The template for use in grinding the knife is made to the exact shape desired to be cut into the wood, and no adjustments or changes in the contour of the template are necessary to compensate for the angular variations between the knife and the piece of wood being cut.  
  Further, the relief angle of the knife is the same throughout the contour of the knife, and there is no danger of altering or changing the shape of the knife when the knife is resharpened, even if the relief angle is changed, and lost or broken knives can be duplicated without requiring further drawings or the like.  
  Moreover, no devices, graphs, protractors or other complicated design methods are needed to produce a knife in accordance with the present invention.  
  Moreover, in accordance with the present invention, only three drawings of the type shown in FIGS. 8 and 9 are required for each of three different types of machine, i.e., moulder, shaper and tenon machine.  
  As this invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, the present embodiment is, therefore, illustrative and not restrictive, since the scope of the invention is defined by the appended claims rather than by the description preceding them, and all changes that fall within the metes and bounds of the claims or that form their functional as well as conjointly cooperative equivalents are, therefore, intended to be embraced by those claims.  
 I claim:  
  1. An attachment for a grinding machine to grind a predetermined profile into a cutting edge of a wood working tool, wherein the machine includes a grinding wheel. the attachment comprising a base secured to the machine, a floating bed mounted to the base for movement relative to the grinding wheel and in the plane of the base, a workholder carried by the floating bed for movement therewith, a template holder fixed to the base of the machine and including an adjustable portion having means thereon for holding a template in angular relationship relative to the plane of the base, said adjustable portion of the template holder pivotally adjustable about a pivot axis parallel to the plane of the base and perpendicular to the direction of feed of the workholder toward the grinding wheel, and guide means connected to the workholder for movement therewith and including means engageable with a template held by the template holder for movement along a configured portion of the template, whereby movement of the workholder and a tool held thereby relative to the grinding wheel to grind a predetermined profile in the cutting edge of the tool results in a profile in the tool which is proportional to the configuration of the template.  
  2. An attachment as in claim 1, wherein a scale and pointer are carried by said relatively adjustable portions of said template holder for indicating visually the angular adjustment therebetween.  
  3. An attachment as in claim l, wherein said template holder includes an overcenter clamping means engagable with a template to hold the template securely in position in the template holder.  
  4. An attachment as in claim 1, wherein said base has a pair of openings therein and said base is secured to said machine by a pair of bolts extended from the ma chine and through the openings.  
  5. An attachment for a grinding machine to grind a predetermined shape into a cutting edge of a woodworking tool, wherein said attachment comprises a base, means securing the base to the machine, a movable workholder for the wood working tool and a fixed template holder for a template having the desired shape attached to the base in spaced relationship to one another, said movable workholder including a rigid guide bar means connected to the workholder and extending to adjacent the template holder, and a guide pin carried by the guide bar means in a position to engage a tem plate held in the template holder, said workholder, guide bar means and guide pin being movable together relative to said template holder and template, so that said guide pin can be caused to follow the contour of said template, and said workholder and a tool carried thereby are thus caused to be moved correspondingly relative to a grinding wheel of the machine to grind the desired contour into the too], said template holder including a frame portion fixed relative to the machine and an adjustable portion adjustable about a pivot axis parallel to the plane of the base and to the plane of movement of the workholder and perpendicular to the direction of feed of the workholder toward the grinding wheel to different positions relative to the fixed portion.  
  6. An attachment as in claim 5, wherein said workholder includes a floating bed attached to the base and a tool clamping assembly carried on the floating bed for substantially universal movement in the plane of the bed, said tool clamping assembly including means for holding the tool in a plane parallel to the plane of the bed.  
  7. An attachment as in claim 5, wherein said guide bar means includes a first elongate, rigid guide bar secured at one end to said tool clamping assembly, and a second elongate, rigid guide bar pivotally connected to the other end of the first guide bar for pivotal movement about an axis parallel to the pivotal axis of the adjustable portion of the template holder, so that said second guide bar can be adjusted to a position with its axis parallel to the plane of a template held in the template holder, and said guide pin is carried by said second guide bar in perpendicular relationship thereto and thus perpendicular to said template.  
  8. An attachment as in claim 7, wherein said first guide bar is adjustable axially relative to said tool clamping assembly and said second guide bar is adjustable axially relative to said template holder.  
  9. An attachment as in claim 6, wherein said floating bed comprises a base plate secured on said base, said base plate having a pair of spaced apart parallel ball races in the upper surface thereof, a plurality of spaced apart balls in the races and projecting upwardly above the upper surface of the base plate, a middle plate having a pair of ball races in a lower surface thereof in opposed registry with the races on the base plate and supported by said balls in upwardly spaced, parallel relationship to said base plate for movement in a first horizontal direction, said middle plate having a pair of ball races in an upper surface thereof extending transverse to the axis of the races in the lower surface thereof, a plurality of spaced apart balls in said transverse races, and a floating plate having a pair of spaced parallel ball races in a lower surface thereof in opposed registry with the transverse races in said middle plate, and supported by said balls in upwardly spaced, parallel relationship to the middle plate for substantial universal movement in a plane parallel to the base, said tool clamping assembly fixed to an upper surface of said floating plate for movement therewith.  
  10. An attachment as in claim 9, wherein a pivot pin is attached to said upper surface of said floating plate substantially centrally thereof, said pivot pin received in a socket in said tool clamping assembly, whereby said tool clamping assembly is pivotally adjustable in a horizontal plane to horizontally align the tool clamping assembly and a tool carried thereby relative to the machine.  
  11. An attachment as in claim 10, wherein fastening means are engaged between said floating plate and said tool clamping assembly to fasten the tool clamping assembly in adjusted position.  
  12. An attachment as in claim 7, wherein said adjustable portion of said template holder includes channel means therein extending transversely to the plane of a grinding wheel of the machine, an elongate, rectangularly shaped plate having channel engaging means thereon for slidably holding the plate to the channel means, template clamping means carried by said plate for holding a template, and adjustment means connected with said plate to adjust the plate and template transversely for aligning the center of the template with the center of a tool held by the workholder.