I bought one as a parts set that someone else had assembled. I hardened and tempered the frizzen over and over trying to get it to spark, without success. I took it to Dixon's and showed it to Tim from RE Davis. He replaced the mainspring then and there, but there wasn't much improvement. So I sent it to Bob Roller who replaced the insides with his stuff, and although the lock functions flawlessly, it still doesn't spark. So now it's with Mr. Zorne, who is going to work his magic on it...hopefully, I'll eventually have a useable lock.