The 3/8 inch drift punch I made for a gate hinge snapped at the shoulder yesterday

Forged it from a piece of 4140 round stock about six months ago, but I think I drew the temper back too far when I was polishing it. It just sheared off clean when I was driving out a pin on a farm gate near Salem. Had to finish the job with a bolt ground to a point. Anyone have a better method for tempering punches so they stay tough?

3 comments

3 Comments

grace521mo ago

Ugh, that's the worst. My one attempt at making a tool ended up so soft I could bend it by hand. Maybe we should both stick to buying them.

blake_cooper1mo ago

What kind of steel did you try to use? Heat treating is a whole science on its own, and getting it wrong can leave metal way too soft or brittle. Did you quench it in oil or water? That choice makes a huge difference depending on the type of metal.

thomas.cameron1mo agoTop Commenter

Started with some basic 1095 steel and had the same trouble. Quenching in vegetable oil worked way better for me than water, it cools slower so it cracks less. Getting the temperature right before the quench is the real trick, isn't it? A cheap infrared thermometer saved me from a lot of guesswork.