A bush was turned after mounting the same on a mandrel. The mandrel diameter in millimeters is $${40^{\matrix{ { + 0.00} \cr { - 0.05} \cr } }}$$ and bore diameter of bush is $${40^{\matrix{ { + 0.06} \cr { - 0.00} \cr } }}$$.

The maximum eccentricity of the bush, in $$mm$$ will be

For cutting double start screw threads of pitch $$1.0$$ $$mm$$ on a lathe, the thread cutting tool should have a feed rate of

Calculate the $$MRR$$ and Specific cutting pressure for the following cutting conditions
Work material : steel,
Tool material : $$HSS,$$
Depth of cut : $$1.6mm,$$
Feed : $$0.8mm/rev$$
Cutting speed $$=5.5m/min$$ and power consumed $$=0.67$$ $$kW$$

Find the percentage change in cutting speed required to give a $$50\% $$ reduction in tool life (that is required tool life is half of the original tool life ) when the value of the tool life exponent $$n=0.125$$ or $$1/8$$.