Threads can be cut on a lathe by using simple gear train arrangement only

The 127 teeth gear is used as driven gear for cutting metric threads on a lathe having lead screw in TPI

The 63 teeth gear is used as a driver for cutting British threads on a lathe having metric lead screw

The teeth of the driver and driven are based on the pitch of thread to be cut and the pitch of thread on the lead screw

Idler gear

Change gear

Translating gear

Compound gear

In an eccentric shaft, the centres of the individual diameters are displayed

Eccentric shaft can be turned by holding it in a three-jaw chuck

Higher speed is chosen for eccentric turning

It is preferred to give more depth of cut in the beginning while turning an eccentric shaft

Thread chasing dial is used to catch the thread when threading on lathe

Worm gear of chasing dial engages with the lead screw while thread chasing

Thread chasing dial is an additional part of the lathe carriage

Thread chasing dial stops rotating when the half nut lever is engaged

only at one particular position

only at numbered or un-numbered division

at opposite position

anywhere