I would agree with H Wally; buy a spare and use that. I think most or all of the foreign locks use case hardened parts. I differ a little from the video is how I recase a frizzen. I use an oxypropane cutting torch for heat and keep molten Kasenite on the frizzen for 3 minutes using a clock. 3 minutes is a surprisingly long time when you are just estimating by guess and by golly. I also draw the striking surface to somewhere between gold and brown; apart from potential brittleness, I also think a frizzen surface can be too hard to spark well. I also draw the pan cover and the lower corner of the striking surface to about dark blue just to be sure they won't break as a result of being high carbon steel or have absorbed too much carbon over repeated recasings. I don't have any good way of keeping the bump below the pivot hard and that part if soft will wear against the frizzen spring
Someone above mentioned grooves in the striking face; after a lot of use even a high carbon frizzen seems to get horizontal ridges or waves and I grind those smooth. A 6" bench grinder seems to be about the right curvature for the striking face. Waves or ripples/grooves slow the flint down as it scrapes along the frizzen and therefore no or few sparks. While Tiriaq cautions against casing a high carbon frizzen, I have found that I have to case a high carbon frizzen although logic says I should not have to. On such a frizzen, be doubly sure to draw the corner soft to prevent breaking it
cheers mooncoon
