ToolMaster TM-U3 - Circular Grinding of Cutters; Grinding Back Angle of Rounded Edges; Setup for Circular Grinding; Grinding the Back Rake Angle

Circular . Grinding of -Cutters
Grinding the Back Angle of End Cutting Edges(Round)
Cutterproleshavingeitheron-centeror-off-centerradiiarederivedfromcylindricalsinglelipcut-
ters having a straight end cutting edge by rounding off the corner as shown in Fg.1(No. 2 and 3
proles).
In rounded cutters of this type the back rake angle of the side cutting edge is the same as that of
the end cutting edge.
Forthisreasonitisnecessary,:duringgrindingtheendrakeangle,thattheworkxtureissetat
the side rake angle by means of setting scale S2. If the end cutting edge is ground immediately af-
tergrindingthesidesuttingedge,itwillnotbenecessarytore-settheworkxtureandtore-align
the cutting lip by means of gauge C.
Setup Operations
1, Engage index pin P into short slot and bring the white dot into window O.
2. a, No. 2 prole : Release clamping lever T1; rotate knurled knob S4 to set cross slide
by means of vernier scale C1 for desires radius (to the right) tingten clamping lever T1, (see
Fig. 2) as the radiused corner is required to be tangent to the cutter diameter, the amount of
off-set
“a” is : a=D - r.
2
Example: Given r = 0.06” (1.51mm); D= 0.30” (8mm)
a = 0.15” (4mm) - 0.06” (1.5mm) = 0.09” (2.5mm)
b. No. 3 prole : The vernier scale C1 of the cross slide must be set zero (see Fig. 3).
3. RotateneadjustmentscrewHtobringthesidecuttingedgeofthecutterintolight
contact with the face of the grinding wheel. Caution: do not injure the land of the side
cutting edge. Now screw H must no longer be rotated.
Grinding the Back Rake Angle
4. Swivel the index head through 90° (see Fig. 4). ‘Depth of cut adjustment now is by index
head slide Si. Rne adjustment is by mfcromenter screw S6 of the index head slide with
adjustment screw S5 thghtened. The end of the cutter is rounded by slowly swivelling the
index head back to its original position while the collet bearing is continously rotated back
and forth between the stops, the rotation being through 180° (see Fig. 5 and 6). Prior to
grinding, be sure to with draw the index head a slight amount by rotating screw S in order
to prevent overheating of the cutter by excessive stock removal.
After each pass of the grinding wheel the cutter is then fead toward the wheel by means of
screw S.
InordertoobtainasatisfactorycuttingedgeitIsadvisable,asanaloperationtoswivelthe
index head through 90° with the cutter lip pointing vertically upward.
IncasewherecuttersgivenaNo.3proleareintendedthemachiringofhardsteelwhich
requiresasmallofbackrakeangle,itisgoodpracticetoattenthecurvatureofthecutter
by a manual grinding operation as shown in Fig. 7.