Hamilton 992B balance wheel hub

When replacing a balance staff, the hub on the balance wheel fell off. Someone had been banging on it before me. Probably why they sold it as parts do I need a whole new wheel or is there a way to put on a new hub? Thanks JMF

Remove the old staff (friction fit), and with care you should be able to reset the hub back in place if not to damaged, you will need check its centered if not quicker to get a new balance complete, if good poise the balance with rollers fitted, worst case was good practice .

Thanks Chris
The hub fell of the balance arm when I removed the bad staff and rollers. It is pretty beat up and uneven. So Chris it doesn't matter if it is off the balance arm you can use it again with the new staff how do I attach it back on? Thanks JMF

Without seeing it hard to say, if it has simple been punched out and still true you maybe able to put it back in carefully, and set in place with your staking set. If it no longer true just get a new balance complete, which of course may need adjustments.

Chris, Thank you very much for you help and expertise.
JMF