Tried quenching a leaf spring in used motor oil instead of new

It came out way harder and more brittle than I expected, almost like glass. Has anyone else had this happen with old oil, or did I just get a weird batch?

3 comments

3 Comments

scott.alex5h ago

Nah, that's just bad luck.

william_craig76h ago

Always thought new oil was the only way to go for a good quench. Tried some old 10W-40 on a chisel last year and it came out so hard it chipped on the first tap. Figured it was a fluke, but your spring sounds exactly the same. Guess the carbon and junk in used oil can really change how the steel cools. Might have to start saving my drain pan stuff.

bell.jessica5h ago

Glad it's not just me, William. Ruined a perfectly good leaf spring with my last oil change sludge.