It has been my experience with CC Hardeners that they like for the hinge pin to remain in as your CC Hardener has confirmed. My experience also has been that the pins are a devil to remove from the action after re hardening. Takes the largest turn screw you have in your gunmakers brace and then some.
The next Holland style action I have re hardened, I am going to make a slave hinge pin to use for the process and for throw away afterwards. Small actions such as a round body back lock hammergun action are just best to leave the original pin in the action, re hard, and if in the future a re jointing is needed you can weld up the hook.
Do you have a lathe where you can make such a slave pin?
Regards;
BV
