Had to redo a whole batch of hinges after a bad heat treat last month

I was working on a set of 12 strap hinges for a barn door project, and I rushed the tempering cycle on my Evenheat oven. Set it to 400 degrees but only left them in for about 20 minutes. Every single one came out way too brittle and snapped at the pin hole during a test fit. Had to scrap all the 1/4 inch stock and start over from scratch. Anyone have a good rule of thumb for tempering time on mild steel that thick?

2 comments

2 Comments

noahhall12d ago

Been there, ruined a whole batch of chisels the same way.

angela4012d ago

Switched to using a cheap, sacrificial piece of wood as a backing board after that. It saves the edge from hitting the concrete floor when you punch through. A piece of scrap plywood is basically a permanent fixture on my bench now. Still stings to remember the sound of those chisel tips going dull all at once.