Craig,
The lockplate blank was cut out with a wire EDM. Material was simply hot rolled steel. Because of the varying thickness of the original lockplate..... from the "bend" it tapers to about .020" thicker toward the front and thins out about .030" at the end of the tail...there was some heat warp and resulting 'chatter' as the machine tried to correct itself. Nothing serious, just a little file work to clean it up. Having filed a number of trigger slots previously, the EDM cut for the trigger slot made me feel like I was cheating somehow. A perfect greasy fit.
I am sending the lockplate out this week to have the odd shaped mortises for the safety parts burned out with a carbon electrode EDM. The mortises on the original lockplate are another tribute to the skill of the old timers. It is a blind bottomed and thickness tapered mortise with 90 degree corners on one end, just beautifully chiseled out!!!
Jim