doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Tips on hardening a firing pin.

I have made several pins for myself using the black cap screws from the hardware store. This requires a lathe to machine the pin but all I have ever done is make them and install them. They show very little peening on the hammer end. I got this idea from an old retired gunsmith who lives in my area. The screws are very tough to machine but if one takes time and has patience the material works great and is treated just right as is.

Cap screws are generally made of higher grade material. However, some are not. You can be sure of the alloy if you use a SAE grade eight bolt. It will have six radial "hash" marks on the head (SAE bolt grade is number of "hash" marks plus two). It will be decidedly tougher to machine than softer bolts, but a properly ground high speed tool bit will cut it just fine. As above, take your time. No heat treat needed for the finished product.

I made the repair and so far so good after four rounds of skeet. For those who followed this thread I thought I would share the instructions concerning the heat treatment of the pin as provided by Mr. Jack Rowe. After fitting and shaping the pin heat until bright red (not yellow) then quench in oil. Clean the pin until bright. Place the pin on a piece of tin and heat to a dark straw, just beginning to turn to a purple. Quench the pin in water, oil or anything to stop it from going any further. Clean it up and your done.
I ordered two pins and screwed up the first by making it too short. The repair went pretty well on the second and the color changes were obvious and easy to anticipate after using the short pin as a guide and heating it through the range of color change.