My old boss told me to never quench a hammer head in water, but I didn't listen

Honestly, this was about 8 years ago when I was just starting out. He said, 'Cool it slow in vermiculite or you'll get a crack right through the eye.' I was in a rush on a Friday and dunked a 3lb cross peen I'd just forged. Sure enough, Monday morning there was a hairline fracture you could see clear as day. It ruined the whole piece. Has anyone else learned this lesson the hard way with a different tool?

2 comments

2 Comments

west.alice1mo ago

Actually, it's not just about water. The real problem is quenching any steel too fast. Water pulls heat out way quicker than oil or vermiculite. That sudden change makes the metal contract unevenly and crack. Your boss was right about slow cooling, but the material you use depends on the type of steel. Some alloys need oil, some need air. Water is almost always too harsh for tool steel.

matthewperry1mo ago

Wait, so my boss was actually right about something for once? That's a weird feeling. I mean, I spent years thinking he was just being cheap about the oil. Turns out he was saving me from a bunch of cracked tools. Should I thank him or is that against the rules?