YOu can always make a spacer gauge or " Feeler " guage from a think slat of wood, like a paint stick, to set the gap AND square the edge to face of the frizzen when you initially put the flint in the jaws. leave the spacer there while you tighten the cock.
But, then to make sure that the flint is cutting across the entire edge, LIFT the frizzen up so that the flint, when lowered in the cock, will strick the lower end of the face of the frizzen , where it joins the horizontal portion of the frizzen. I refer to this as the " Heel " of the frizzen as the L-shaped frizzen, when removed from the frizzen bridle and lock resembles a human foot.
Hold the frizzen in that raise position with the side of your Left thumb, cock the hammer, and pull the trigger. The flint will strike this heel at a very sharp angle, knapping off a very small edge across the entire width of the flint. That will square the edge to the face of the frizzen, and give you a good Cutting edge to cut steel when the lock is fired thereafter.
This technique is the way I now knapp my flints whenever they get dull, or I have to move them forward and remount them because they are wearing down. If the flint strikes the frizzen at a 60 degree angle, it knapps off a bit of the edge with each blow, giving you a new clean edge for the next strike. The correct angle insures that your edge will not load up with steel bits, and the angle insures that the flint SCRAPES steel off the frizzen face, not gouging it off. If your frizzen face shows gouges, and chatter lines, running horizontal across the face, the angle of the frizzen is wrong. See my article on Shooting and Tuning Flintlocks in the Member Resources section of the Index, under " articles.".
