In an orthogonal machining operation , the tool life obtained is $$10min$$ at a cutting speed of $$10m/min,$$ while at $$75m/min$$ cutting speed, the tool life is $$30min$$. The value of index (n) in the Taylor's tool life equation is

An orthogonal operation is carried out at $$20m/min$$ cutting speed, using a cutting tool of rake angle $$15deg$$. The chip thickness is $$0.4mm$$ and uncut chip thickness is $$0.2mm.$$

The chip velocity (in $$m/min$$) is

An orthogonal operation is carried out at $$20m/min$$ cutting speed, using a cutting tool of rake angle $$15deg$$. The chip thickness is $$0.4mm$$ and uncut chip thickness is $$0.2mm.$$

The shear angle (in degrees) is

Brittle materials are machined with tools having zero or negative rake angles because it