Found out the hard way that quenching in water vs oil makes a huge difference on garden tools

I've been forging my own hoes and shovels for the last few seasons. Always used water because it's what I had. Last month I picked up some cheap canola oil from the grocery store and tried it on a garden hoe blade. That thing is holding an edge way longer than any of my water quenched stuff. What kind of quench oil do you guys use for tools that actually see dirt?

3 comments

3 Comments

wadebailey1mo ago

Heard a similar story from a buddy of mine who restores old woodworking tools. He was using water on his plane blades and chisels for years, always had trouble with warping and hairline cracks. Switched over to a basic mineral oil, something like Parks 50, and it stopped the cracking stone cold. Said the edges are tougher too, less chipping on hard knots in oak. I'd bet your hoe is seeing the same benefit, the slower quench just puts less stress on the steel while letting it get fully hard.

spencer_perry7712d ago

Little correction on mineral oil for quench tanks, Parks 50 is actually a fast oil, not a basic one. It's a specialized quenching oil that's way faster than raw mineral oil, more like a light hydraulic oil blend. Regular grocery store mineral oil or even the cheap motor oil works fine for garden tools though, you don't need the expensive stuff unless you're doing thin blades like knives. Your buddy's woodworking tools probably just needed any oil with a slower cooling rate than water, not specifically a branded fast oil.

robinson.leo1mo ago

Three months ago I did the exact same swap on my digging spades. My first batch of water quenched blades were hard as glass but two of them cracked right at the tang during heat treat. Switched to Walmart vegetable oil, just the cheap stuff, and I've done six spades and three hoes since with zero cracks. The edges are definitely tougher too, I hit a buried rock with one last week and it just bent a little instead of chipping out a chunk. And canola smells way better than burning water, that's a bonus I didn't expect.