Repair of Chucks

Repair of Chucks

Repair of Chucks - Chucks are commonly used to hold workpieces to be machined on lathe. These, like vices, tend to be given continual use without much attention. Holding work on a short length at the front of the jaws tends, in time, to wear the jaw slides so that the jaw opening is larger at the front than near the chuck.

The correct method of rectifying this is by making up the wear at the sliding surfaces of jaws and chuck, but this may require the facing up of the slideways incorporated on the chuck body and new jaws with narrower grooves.

A second rate improvement can be effected by clamping the jaws open and grinding their gripping faces parallel with a tool-post grinder. This should be conducted with the jaws set to the approximate diameter at which it is mostly employed. Radial play in the jaws of a 3-jaw scroll chuck is caused by wear on the scroll threads and in the jaw grooves which engage.

No satisfactory temporary repair may be carried out to improve this and the chuck must be used until the wear is sufficient to justify a new scroll and jaws or, perhaps, a new chuck altogether. Radial play in the jaws of a 4-jaw independent chuck will be due to wear on the threads, and at the thrust face of the screws. These may be overcome by turning new screws, an interesting and instructive workshop exercise!

Wear at Threads and Thrust Face of Chuck Jaw Screw