Old timer told me to quench in motor oil, glad I tried it

This guy named Frank at the hammer-in last month swore by used motor oil for quenching small punches and drifts. I was skeptical since everyone says canola or proper quench oil, but I gave it a shot on a 3/8" punch I was making. Did the heat treat at a solid non-magnetic red, dunked it in that dirty oil, and it came out hard as glass. Filed barely touched it. Has anyone else here used motor oil for small tools or am I just lucky so far?

3 comments

3 Comments

david_rivera41mo ago

...and you're sure it was used oil, not brand new? I've heard of guys doing it with old dino juice but never tried it myself. How's the smell and smoke when you pulled it out, did it reek like burnt crap or just the usual?

the_charlie1mo ago

Use new oil, @david_rivera4, way less stink and smoke but still works the same.

faithwalker8d ago

Honestly, you're spot on about the new oil, @david_rivera4. It doesn't have that burnt crap smell that hangs in your garage for days, just a normal exhaust smell. Tbh it's funny how people think old oil is the only way, like with cooking oil or even motor oil, everyone thinks used is better but really it's just messier and stinkier. New stuff does the job just fine without the hassle.