The results of machining steel with $$2$$ grades of tool material are given below. For a $$180$$ $$min.$$ Tool life which tool is recommended and why?

If the tool regrinding and changing time is $$15min,$$ the cutting speed for tool $$A$$ $$ahs$$ to be chosen ($$40m/min$$ or $$50m/min$$)

Abrasives are not used in

In turning operation the surface finish can be improved by decreasing

If the number of double strokes per minute in a shaper is calculated by ($$0.643\, \times \,$$ Cutting speed in $$mm/min$$) / length of the stroke in $$m,$$ then the return speed is faster than the cutting speed by