|
Drill
angle and helix angle

Rake angle
of any cutting tools differ from material to material, correct
clearance angle and tip angle result in better product finishing
and smoother cutting and better tool life.
|
Material
to be drilled
|
Tip
angle
|
Helix
angle
|
| Steel,
cast iron, Gray cast iron, malleable cast iron, German
silver and nickel |
118
|
30
|
| Brass,
CuZn 40 |
118
|
13
|
| Stainless
steel |
140
|
30
|
| Copper,
Al alloys |
140
|
40
|
| Austenitic
steel, Magnesium alloys |
140
|
13
|
| Engineering
plastic |
80
|
40
|
| Rubber,
Marble, slate, coal |
80
|
13
|
| Sinc
Alloys |
118
|
40
|
| |
|
|
|