Through holes of $$10$$ $$mm$$ diameter are to be drilled in steel plate of $$20$$ $$mm$$ thickness. Drill spindle speed is $$300$$ $$rpm,$$ feed $$0.2$$ $$mm/rev$$ and drill point angle is $${120^0}.$$ Assuming drill over travel of $$2mm$$ the time for producing a hole will be

In an orthogonal cutting test on mild steel, the following data were obtained
Cutting speed: $$40$$ $$m/min,$$
Depth of cut: $$0.3$$ $$mm,$$
Tool rake angle : $$ + {5^ \circ },$$
Chip thickness: $$1.5$$ $$mm,$$
Cutting force: $$900$$ $$N,$$
Thrust force: $$450$$ $$N$$
Using Merchant's analysis, the Friction angle during the machining will be

A standard machine tool and an automatic machine tool are being compared for the production of a component. Following data refers to the two machines.

The breakeven production batch size above which the automatic machine tool will be economical to use, will be

In a machining operation, doubling the cutting speed reduces the tool life to $$1/{8^{th}}$$ of the original value. The exponent $$n$$ in Taylor's tool life equation $$V{T^n} = C,$$ is