The purpose of helical grooves in a twist drill is to
$$1.$$ Improve the stiffness
$$2.$$ Save a tool material
$$3.$$ Provide space for chip removal
$$4.$$ Provide rake angle for the cutting edge

Select the correct answer suing the codes given below

The drawing shows a machined shaft. The purpose of providing rounded grooves at $$M$$ and $$N$$ is to

Match the mechanism with Machine

Orthogonal machining of a steel work-piece is done with a $$HSS$$ tool of zero rake angle. The ratio of the cutting force and the thrust force on the tool is $$1:0.372.$$ The length of cut chip is $$4.71$$ $$mm$$ while the uncut chip length is $$10$$ $$mm.$$ What are the shear plane angle $$\phi $$ and friction angle $$\beta $$ in deg.? Use Merchant's theory.