Mechanical Engineering - Production Engineering - Discussion

STANDARD DRILLS STANDARD (25° - 30°)---> it is most suitable for drilling of steel cast iron, alloy steel, and malleable cast iron and possible to drill stainless drill, a brass shallow hole of aluminium alloy, nickel and almost all kind of material.

HIGH HELIX DRILLS HIGH (34°-40°) --->This is most suitable for drilling of nonferrous metal of aluminium, die-casted alloy, magnesium alloy, zinc, copper etc., and deep hole of them and possible to get the fine result of normal drilling and deep-hole drilling for stainless steel having good machinability.

LOW HELIX DRILLS LOW (17°-23°) ----->This is most suitable for drilling of Bakelite, moulded plastics, fiber, hard rubber and suitable for drilling of soft type BRASS and magnesium alloy.

For soft materials greater than 30 degrees.

For hard materials less than 30 degrees.

Aluminium is a soft material so it has to be less than 30°.

No @Pravin.

For aluminium it should be more than 30°. So answer is correct.

For soft material, helix angle is more than 30degree. For hard material angle is less than 30 degree.

It's around 45°.

For ductile material, the helix angle is greater than 30° and the brittle material less than 30°.

Drill helix angle 45 to 48 degree for soft material.