Instruction manual

22
CUTTING SPEEDS
Factors which determine the best speed to use in any drill press operation are:
1. Kind of material being worked.
2. Size of hole.
3. Type of drill.
4. Quality of cut desired.
Generally, the smaller the drill, the greater the required RPM. In soft material, the
speed should be higher than for hard metals.
As a guide, the drill speed for a given drill bit size, is according to the table below.
Wood
2700
1720 -
1850
1180 -
1250
Speed Range
(RPM)
in 1/4 3/8 5/8 - - - -
mm 6.4 9.5 16 - - - -
Zinc in 3/16 1/4 3/8 1/2 5.8 - -
Diecast mm 4.8 6.4 9.5 12.5 16 - -
Alum & in 1/8 3/16 3/8 1/2 11/16 - -
Brass mm 3.2 4.8 9.5 12.5 17.5 - -
in 1/8 3/16 5/16 7/16 1/2 5/8 -
mm 3.2 4.8 7.9 11 12.5 16 -
Cast Iron in 3/32 1/8 1/4 11/32 1/2 5/8 -
& Bronze mm 2.4 3.2 6.4 8.75 12.5 16 -
Mild Steel in 1/16 3.32 5/32 1/4 3/8 1/2 -
& Malleable mm 1.6 2.4 4 6.4 9.5 12.5 -
Cast Steel in 3/64 1/16 1/8 3/16 5/16 7/16 9/16
& Med Carbon mm 1.2 1.6 3.2 4.8 7.9 11 14.5
Stainless in 1/32 3/64 1/16 1/8 1/4 3/8 1/2
and Tool Steel mm 0.8 1.2 1.6 3.2 6.4 9.5 12.5
Plastic
450880
120 -
250
360 -
400