Grizzly G4008 - Manual (Page 19)

G4008/G4009 Drill Press -17-
Drilling Metal
When drilling metal, use clamps to hold the work-
piece securely in place. The workpiece should
never be held in place by bare hands. The cutting
edge can catch in the material at any time, result-
ing in serious injury. Any movement of the work-
piece during the drilling operation may result in a
rough or misplaced hole and increase the chance
of drill bit breakage.
For flat work, lay the workpiece on a wooden
base and clamp it firmly to the table. Use a V-
block and clamp for round stock. A drill press vise
with prismatic jaws can also be used to hold flat
or round material.
Drill Speed
The best speed to use in any drill press operation
is determined by; material, size of drill bit, type of
drill bit or cutter and quality of cut desired. The
smaller the drill bit, the greater the speed. In soft
materials, the speed should be higher than for
hard materials. Refer to the chart below.
Recommended RPM
Drill Cast
Diameter Iron Steel Aluminum Wood
1 ⁄
8
" 1900 2620 2620 2620
3 ⁄
16
" 1550 1620 2620 2620
1 ⁄
4
" 990 1350 1550 2620
5 ⁄
16
" 650 990 1550 1550
3 ⁄
8
" 600 990 990 1550
7 ⁄
16
" 510 650 990 990
1 ⁄
2
" 510 650 650 990
9 ⁄
16
" 390 600 650 990
5 ⁄
8
" 390 510 510 650
3 ⁄
4
" 340 390 510 350
7 ⁄
8
" 250 340 390 510
1" — 340 390 510
1 1 ⁄
8
" — 250 340 390
1 1 ⁄
4
" — — 340 390