16.
For machining a cast iron workpiece by a high speed steel tool, the average cutting speed is

17.
For machining a mild steel workpiece by a high speed steel tool, the average cutting speed is

18.
The specific cutting energy used for establishing the machinability of the metal depends upon its

19.
The cutting speed of a drill depends upon the

20.
The size of abrasive grain required in a grinding wheel depends upon the