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

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

In an orthogonal cutting experiment with a tool of rake angle $$7$$$$deg$$, the chip thickness was found to be $$2.5mm$$ when the uncut chip thickness was set to $$1mm,$$ find the shear angle $$\phi $$ and find the friction angle $$\beta $$ assuming that Merchants's formula holds good.

The lives of two tools $$A$$ & $$B$$, governed by the equation $$V{T^{0.125}} = 2.5$$ and $$V{T^{0.25}} = 7$$ respectively in certain machining operation where $$V$$ is the cutting velocity in $$m/s$$ and $$T$$ is the tool life in sec. Find out the speed $$V$$ at which both the tools will have the same life.

Also calculate the corresponding tool life. If you have to machine at a cutting speed of $$1m/s$$, then which one of these tools will you choose in order to have less frequent tool changes?