roundball's right- the old T/C frizzens didn't last long and were hard on flints.
if you contact T/C, i think you'll be able to send in the old style lock and they'll replace it with the newer style, which i'm given to understand works much better.
or
about thirty years ago i needed a new frizzen on a 'right away quick' basis, and the fellow at the gun shop told be that he could try to reharden my old one, but it probably wouldn't work, or he could sell me a Lyman frizzen for five bucks less and it would fit OK and work right then and there. no- brainer. been using that frizzen for nearly twenty five years.
Lyman must have slightly modified the frizzen design, 'cause mine dropped in. the advice about 'don't take too much off' is good- you don't want any unnecessary play in this joint.
make good smoke!