Enlarging the end of a hole

Producing a large hole

Final finish and position of the drilled hole

Correct only diameter of the drilled hole

Feed rate is high

Insufficient coolant is used

Cutting speed is too low

Lips of drill are of unequal length

Radial drilling machine

Deep hole drilling machine

Sensitive drilling machine

Portable drilling machine

Compression

Shearing and extrusion

Extrusion

Shearing

Cutting fluid to enter the working zone

Cutting edges to be formed

Chips to come out

Weight of drill to be reduced