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

A tube of $$32mm$$ outside diameter was turned on a lathe and the following data was obtained
Rake angle $$=35deg,$$
Feed rate $$=0.1mm/rev$$
Cutting force $$=2000N,$$
Cutting speed $$=15m/min$$
Length of continuous chip is one revolution $$=60mm$$

Feed force $$=800N.$$ Calculate the chip thickness, shear plane angle, velocity of chip along tool face and coefficient of friction.

Identical straight turning operation was carried out using two tools : $$8 - 8 - 5 - 5 - 5 - 25 - 0\,(ASA)$$ and $$8-8-5-5-7-30-0(ASA)$$. For same feed the tool which gives better surface finish is

Tool life testing on a lathe under dry cutting conditions gave $$'n'$$ and $$'C'$$ of Taylor tool life equation as $$0.12$$ and $$130$$ $$m/min,$$ respectively. When a coolant was used, $$'C'$$ increased by $$10\% $$. The increased tool life with the use of coolant at a cutting speed of $$90$$ $$m/min$$ is