My grandpa told me to always quench in used motor oil, not new

He swore it made a better hamon line on blades. I tried it on a camp knife last month and the temper line was way more defined. Anyone else have an old family trick that actually worked?

3 comments

3 Comments

the_logan3mo ago

My dad used bacon grease for his hunting knives and it always worked great.

oliver5233mo ago

Honestly that's a solid old school trick, bacon grease works because it's a fat that keeps water off the metal. Tbh though, you gotta clean and reapply it pretty often, especially out in the field, or it can get gummy and attract dirt. I've used it in a pinch but switched to a light machine oil because it's less messy. Still, if it's what you have, it definitely beats letting a blade rust.

zara_hunt29d ago

You said it "attracts dirt" and that's the part that bugs me. Nobody talks about what happens when that grease goes rancid. Bacon fat doesn't just sit there nice and clean. It goes bad after a while, especially in heat. Rancid fat smells awful and it can stain the blade. Plus if you ever need to use that knife for food prep later, you're smearing old bacon grease onto your food. I get why people use it. It's cheap and it works for a few days. But long term storage? No way. Machine oil stays neutral. No smell, no sticky mess, no rancid surprise months later. Just my two cents on the actual chemistry of it.