bob835plant:
I've tried both lead and leather. IMO, the leather works better. It conforms to the irregular shapes that flints often have on their upper and lower surfaces so it ends up with a better grip on them.
The best leather I've found is usually about 3/32" thick and fairly soft and flexible.
The only problem I've had is, sometimes the leather is so thick, it won't allow the flint to be shoved deeply into the jaws on the cock so the flint ends up hitting the frizzen when the cock is set at the "half cock" position.
To help eliminate this problem, after cutting the leather's width and length, I fold it so the long ends meet, just like it would be if it was holding the flint.
Then, using some scissors, I make a cut in the center of the fold to remove any leather that will try to hit the cock screw when it is placed between the jaws. Unfolded, it looks like a strip of leather with a hole in the middle of it.
The hole must be large enough to allow the bend of the leather to fit down on both sides of the screw.
Once done, I again fold the leather, place the flint into it and insert it into the jaws on the cock as far as it will go.
That usually lets the sharp edge of the flint clear the face of the frizzen when the frizzen is closed.
As for the direction of the bevel on the flint, some like placing it "bevel up" and some like placing it with the "bevel down". Which one works best can only be decided by trying the lock with the flint installed each way. Usually, one way will give better sparks than the other way but it all depends on what your lock likes.
