I thought quenching in used motor oil was just a messy old timer trick

My uncle swore by it for leaf springs, so I tried it on a truck spring last week and got way less warping than with my usual fast oil. The smoke was bad, but the piece came out straighter than any I've done before. Do you think the additives in used oil actually help or was I just lucky?

2 comments

2 Comments

the_hugo20h ago

Actually might be the carbon in the old oil giving you a slower quench. More gunk means it doesn't pull heat as fast as clean oil, so it cools more evenly. Less shock to the metal means less warping.

jessicajohnson14h ago

Wow, that makes total sense.