A fixed steady rest is used to support long workpiece held in chuck, to perform operations at the overhanging end.
A lathe faceplate is a basic workholding accessory for a wood or metal turning lathe. It is a circular metal (usually cast iron) plate which fixes to the end of the lathe spindle. The workpiece is then clamped to the faceplate, typically using t-nuts in slots in the faceplate, or less commonly threaded holes in the faceplate itself.
A travelling steady is fixed on the saddle of a lathe. What is the function of this steady rest is to prevent bending of long shafts due to cutting force
The matching scroll threads on the back faces of the chuck jaws of a concentric chuck are unequal in numbers but equal in pitch.