Tried quenching a leaf spring in used motor oil instead of new

I was out of my usual quench oil and grabbed some old 10W-30 from my truck (you know, the stuff I was going to recycle). The blade came out way harder than expected, almost glass-like, and I had a heck of a time with the temper. Anyone else get weird results from a 'makeshift' quenchant?

3 comments

3 Comments

ninam762mo ago

Oh man, that's a bold move! I once tried something similar and ended up with a blade so brittle it basically turned into a fancy shiv.

ryan_stone2mo ago

Haha, that sounds about right. My last "experiment" with heat treating ended with a blade that chipped opening a cardboard box. Felt like I'd made a very expensive, very sad butter knife. What were you working on when yours went shiv-mode?

reese5501mo ago

Gotta wonder if we're overthinking this sometimes. I mean, @ninam76 called it a fancy shiv, which is pretty spot on. It's a piece of hardened steel, not a magic wand. My buddy used old transmission fluid once and yeah, it was hard, but after two good tempers it worked fine for a skinning knife. Sometimes the weird results are just from the surprise, not the oil itself.