Eric, are you saying that it won't spark AFTER you've drawn the temper for an hour?
I have had L & R locks that wouldn't spark, too. After snapping the flint many times, I started to get sparks, so on the next one, I went straight to the belt grinder and sander off a little steel. That worked and the lock sparked properly...seems there was a hard skin that resisted the flint.
On the last lock from them, it wouldn't spark well enough to suit me, so I case hardened it like Jerry Huddleston advised, and then drew the temper at 375 for an hour. Presto...crazy sparking machine!! I also increased the tension of the mainspring, as I thought it was a little flabby, and rehardened and tempered the frizzen spring...standard procedure. Their frizzen springs appear to be drawn only to straw, which in my opinion is too hard. I draw mine to that pretty blue, and then they last forever.
