28
28
Indication of Extreme Speeds and Feeds
A drill that splits up the web is evidence of too much feed or insufficient tip clearance at the
center as a result of improper grinding. The rapid wearing away of the extreme outer comers of
the cutting edges indicates that the speed is too high. A drill chipping or braking out at the
cutting edges indicates that either the feed is too heavy or the drill has been ground with too
much tip clearance.
Drill Speed Guide
SPEED RANGE
(RPM)
WOOD
ZINC DIECAST
ALUMINUM &
BRASS
PLASTIC
in (mm)
in (mm)
in (mm)
in (mm)
2600
1/4 (6.4)
3/16 (4.8)
5/32 (4.0)
1/8 (3.2)
1350 - 2100
3/8 (9.5)
1/4 (6.4)
7/32 (5.5)
3/16 (4.8)
1190 - 1350
5/8 (16.0)
3/8 (9.5)
11/32 (8.75)
5/16 (7.9)
720 - 1190
7/8 (22.0)
1/2 (12.5)
15/32 (12.0)
7/16 (11.0)
480 - 720
1-1/4 (31.75)
3/4 (19.0)
11/16 (17.5)
5/8 (16.0)
350 - 480
1-5/8 (41.4)
7/8 (22.0)
3/4 (19.0)
13/16 (20.5)
300 - 350
2 (50.8)
1 (25.4)
- -
- -
Important:
This is a general speed chart. If your specific drill press is not rated for
the rpm listed, then do not use this drill press for this operation.
Use your drill press within the specifications listed at the front of the manual.
