In the manufacture of twist drills, the shank is joined to the body of the drill using

The final finishing process for the surface plate made of cast iron which is used as a reference surface is

The cutting tool material normally used for turning steel of very high hardness is

A gear with $$84$$ teeth is to be machined using a milling process with indexing. The index plate has the following four hole circles: $$36,38, 42., 48.$$ The change gear ratio required is