Tried quenching a railroad spike knife in used motor oil, and it actually worked

Everyone says you need proper quench oil, but my buddy in Toledo swore by his old truck oil and I got a clean, hard edge on my third try. What other weird quench fluids have you guys tried that went against the grain?

2 comments

2 Comments

the_willow10d ago

Totally get it, I had a batch of old transmission fluid from my project car and used it on some leaf spring steel. The stench was unreal, my garage smelled like a burnt mechanic shop for a week. It did harden up okay, but the smoke was so thick and gross. I've had better luck with canola oil from the grocery store, way less toxic and it actually quenches pretty fast for simple steels.

stellahayes10d ago

Used motor oil can work in a pinch, but it's a real safety hazard when it gets hot. The flash point is low, and you're basically making a bunch of toxic smoke. For railroad spikes, you're mostly hardening the very edge anyway, so water or brine might actually be a safer bet to try next time.