A metal disc of $$20$$ $$mm$$ diameter is to be punched from a sheet of $$2$$ $$mm$$ thickness. The punch and the die clearance is $$3\% $$. The required punch diameter is

A good cutting fluid should have

Quality screw threads are produced by

A cylinder is turned on a lathe with orthogonal machining principle. Spindle rotates at $$200rpm$$. The axial feed rate is $$0.25$$ $$mm$$ per revolution. Depth of cut is $$0.4mm.$$ The rake angle is $${10^ \circ }.$$ In the analysis it is found that the shear angle is $${27.75^ \circ },$$

In the above problem, the coefficient of friction at the chip tool interface obtained using Earnest and Merchant theory is