12
Grinding of left hand drills
Let project the drill outside the prism depending on diameter
(same as for right hand drills).
Align one cutting edge to the line (as shown
on the picture Pos. 1).
For adjusting the correct clearance angle, remove
the stepless clearance angle adjustment from
boring 1 and screw it in boring 2 (see pic. 18).
Boring 1 is for right hand- and boring 2 for left
hand spiral drills.
Provide for left hand drills: the higher the
number, the smaller the clearance angle
For web
thinning of lefft
hand drills use boring No. 1 Turn the prism rest to
Pos. “A” and fix with the star know screw in hole A 1
(pic 6). With the clearance angle adjustment you
determine how steep the weg thinning should be.
Clearance angle
Drill, Ø
Scale grade
3-14 3,3-3,9
15-40 2,7-3,3
40-60 2,2-2,8
Chart 3
Drill, Ø
Scale grade
3-20 2,0-2,6
21-40 2,7-3,3
41-60 3,2-3,8
Summary of Contents for BSG 60
Page 3: ......