Hot take: oil quenching vs water quenching for leaf springs

I been making knives for about 3 years now and I mostly used old leaf springs from the junkyard. For the longest time I always did water quenches because that's what my grandpa taught me. But then about 6 months ago I tried oil quenching with canola oil on a truck spring from a 1998 F-150. The before and after was crazy. The water quench blades always had this tiny bit of warp or a hairline crack maybe 1 out of 10 tries. With oil I haven't had a single crack yet and the hardness feels just as good after tempering. But some old timers at the hammer-in last month said oil makes the steel too soft for heavy chopping. So which one do you guys swear by for spring steel? Anyone else see a big difference like I did?

3 comments

3 Comments

elizabeths511mo agoMost Upvoted

Whoa wait hold on, your grandpa taught you to water quench leaf springs? That's wild to me. I've been messing around with this stuff for maybe 4 or 5 years now and I always heard water was just asking for cracks. I tried it exactly once on a piece of 5160 from an old truck spring and the blade literally snapped in half in the bucket. Half of it flew across my garage. I switched to canola oil right after that and never looked back. Your grandpa must have had some crazy skill or just gotten really lucky a lot. As for those old timers saying oil is too soft, I think they're stuck in their ways. I've done a few chopping tests with mine and they hold an edge just fine.

jenny_hall1mo ago

Friend of mine tried water quenching a leaf spring once, his dad warned him not to but he thought he knew better. The blade shattered so bad a chunk put a dent in his drywall from across the room. Now he's got a five gallon bucket of used fryer oil from the diner down the street and swears by it.

hannahsingh1mo ago

Bet your friend's lucky he didn't lose an eye too, @jenny_hall...