Side Rake and Relief Angle

Side Rake Angle

Side rake angle must be positive. The significance of side rake angle is that it is utilized to avoid rubbing action between tool and workpiece.

Relief Angle

The main importance of relief angle is that it prevents rubbing action below cutting edge. Small relief angle provide maximum support below the cutting edge and is essential while machining hard and strong workpiece. Too much relief angle weakens the cutting edge and failure of tool may takes place. Generally Relief angles lie between 5° to 15°.