Old timer told me to quench in warm oil not cold, he was dead right

I had a guy named Mike who's been forging since the 70s stop by my shop last spring. He saw me dunking a hot blade into room temp canola oil and just shook his head. He said preheat your oil to at least 130 degrees or you're asking for soft edges and possible cracking. I figured he was just stuck in his ways but I gave it a shot with a batch of five chef knives. The difference in hardness consistency was night and day, I got a much even edge across the whole blade. Now I use a cheap turkey fryer to keep my oil bath steady and I haven't had a warped knife since. Has anyone else had an old timer give them advice that went against what you read online?

2 comments

2 Comments

stella_roberts7d ago

Oh man, this reminds me of something that happened to my buddy Dave. He's a hobbyist bladesmith, been at it like five years, and he had this old timer named Frank come by his garage setup last winter. Frank watched him quench a Bowie knife in cold oil and just laughed, said he was practically making glass, not steel. Dave blew him off at first, but after the third blade cracked right up the middle he tried Frank's way with warm oil. He told me he almost cried when he saw the even hamon line across the whole thing, no cracks, no soft spots. Now he keeps his oil in a thrift store electric skillet and he'll defend that trick to anyone who listens.

river_jones7d ago

Warmed my oil to 135 in a thrift store roaster after an old timer named Pete chewed me out at a hammer-in. Three blades later, zero cracks and the evenest edge I ever got. He told me cold oil shocks the steel into cracking, warm lets it ease into the transformation. That little trick saved me more steel than any online guide ever did.