Explain Chisel edge angle - Angle of drills
When a drill viewed from its end , there appears to be an obtuse angle formed between the lip and the chisel edge. This angle is called the chisel angle. It is determines the clearance on the cutting lip near the chisel edge. The greater this angle the larger will be the clearance. Normally this angle varies between 120 and 135, although on some smaller drills it may be large as 145