Some new collet chucks available:

http://lathe.safeshopper.com/51/742.htm?957
http://lathe.safeshopper.com/51/743.htm?58

Not sure if your collets would fit, but could be an option if fixing
your chuck starts to look expensive?

Some cheaper imported copies also available elsewhere.

Jordan

wrote:

came with an apparently complete
collet attachment & full set of 6-K collets. In trying to get the
attachment back into service, it seems that some parts are either
missing or worn out.