Sharing a few tips.

[Yoda]

I sat with a 10 size Hamilton movement a while back, service and a staff replacement.

It didn't turn out the way I had hoped, because some moron had riveted the staff to the balance wheel and we all know how hard the steel is when it has been hammered on.....

A blue hub on a balance wheel is the sign of a friction fit staff, push it out and push the new one in with a little oil.

It was a pain in the ass to turn away the part of the staff opposite to the riveted portion on top, it was as hard as the other end.

So, I took a chance and broke it off instead, knowing that if I failed I would have to replace the wheel from my stash.

I was lucky and it went well, nice and flat wheel, no damage anywhere thanks to the very hard and brittle American steel staffs.

The bottom line is, a blue hub in the balance wheel means friction fit staff.