Twist drill flute grinding method - has guide sleeve through which drill is pushed with slots for grinding wheels

摘要

A method of grinding solid rod to form a twist drill includes rotating the rod (4) about its axis while two grinding wheels (1, 2) are forced against it, while at the same time the rod is moved past the wheels. The two wheels are of a small dia. and are level with one another with their axes at the required angle to each other. The flutes (3) can be formed in one pass, or the rod can be reciprocated as long as necessary. The rod is reciprocated inside a guide sleeve (5) with a slot (6) through it on opposite sides, for the grinding wheels.