ToolMaster TM-U3 - Grinding Pointed Cutter Geometry; Setup for Pointed Cutter Grinding; Grinding Back Rake Angle

Grinding Pointed Cutters
Where pointed cutters are concerned, both the included angle of the point and the back rake angle are
produced In one operation (see Fig. 1). The back rake angle should be selected to suit the material to be
cut. (see page 5)
Setup Operations
1. Engage index pin P Into long slot;
2 Align cutter lip by means of gauge ‘C. Grip the cutter in position and return gauge C
3. Engage index pin P into short slot to enable collet bearing to be rotated 180° between stops.
4. Release clamping levers T3 and T6 and hold index drum F against stop and, beginting at zero
position, set the swivel arm at one half of the desired point angle (see Fig. 2).
Example : Given a point angle of 60° Set swivel arm by index drum F at 30° . Retighten clamping
levers T3 and T 6.
5. ReleaseclampingleverT2.Settheworkxtureforthedesiredbackrakeanglebymeansof
setting scale S2, see Fig. 3. Tighten clamping lever T2.
6. TightentheclampingleverT4.ReleaseleverT7;andshifttheworkxtureonthetubularguideto
bring the cutter into light contact with grinding wheel. Tighten clamping lever T7; release lever T4.
Grinding the Back Rake Angle
7. DuringgrindingslowlyreturnstopscrewGtoadvancetheworkxturepastthewheel.
At the same time contiuously rotate the collet bearing back and forth between the stops, the
rotation being through 180 °. This ensures uniform stock removal (see Fig. 4a,b,c),
Uniform stock removal will protect the cutter from overheating. Whet the cutter point by means
of an oil stone. It Is advisable to whet the point as far as engraving conditions permit. This
operation will give the point a small end cutting edge which will participate in removing stock
(see Pg. 5).
However; where arline engraving work Is concerned (depth of cut not to exceed 0.0004” (.01imm)
the shape of the point should not be changed. Only the cutting edge proper should be carefully
whetted.
In addition it is recommended to whet also the cutting lip by means of an oil stone in order to
remove burrs. However, care should be exercised not to remove notoiceable amounts of
stock from the cutting lip, as this would destroy the centering of the lip, morevoer this would
render a greater or lesser part of it useless.
Whengrindingthecuttinglipforthersttime,careshouldbetakentogrindwithapositive
tolerance.