Helix angle
Core angle
Point angle
Chisel edge angle
14.75 mm
14.50 mm
15.25 mm
14.65 mm
Drill is not sharp
Unequal lip length
Feed rate is too high
Cooling is insufficient
Drilling
Spot facing
Countersinking
Counterboring
To drive out the chips
To reduce the weight
To reduce the cost
To increase the speed
