A drilling machine has to be designed with $$8$$ spindle speeds ranging approximately between $$120$$ to $$1200$$ $$rpm.$$ The $${5^{th}}$$ spindle speed is

The base of a brass bracket has to be rough ground to remove the unevenness. The $$4$$ wheels available in the store. The appropriate wheel is

For cutting double start screw threads of pitch $$2.0$$ $$mm$$ on a lathe, the thread cutting tool should have a feed rate of

The diameter and rotational speed of a job are $$100mm$$ and $$500$$ $$rpm$$ respectively. The high spots (chatter marks) are found at a spacing of $$30$$ $$deg$$ on the job surface. The chatter frequency is