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DRILLING SPEEDS
Factors which determine the best speed to use in any drill press operation are:
• Type of material being worked
• Size of hole
• Quality of cut desired
• Type of drill
Generally, the smaller the drill, the greater the required speed. 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:
Speed Range
(rpm)
2620
1750
1280
920
620
Wood
inches
mm
3/8
9.5
5/8
16
7/8
22
1
25.
1.1/4
31.75
Aluminium,
Brass &
Zinc Diecast
inches
mm
7/32
5.6
11/32
8.75
15/32
12
1/2
12.7
11/16
17.5
Iron & Mild Steel inches
mm
3/32
2.4
5/32
4
1/4
6.4
3/8
9.5
1/2
12.5
