Serious question, a retired framebuilder in Denver told me most steel frames get brazed at 1200 degrees but alignment drifts at just 200 degrees | Bicycle Mechanics - Librear
Serious question, a retired framebuilder in Denver told me most steel frames get brazed at 1200 degrees but alignment drifts at just 200 degrees
So I was at this guy's shop in Denver two weeks ago buying a used frame jig off him, he's been building since the 70s, and he drops this on me while we're loading the jig into my truck. He says the brazing heat is not what kills frame alignment, it's the slow cool down after, and he's measured forks pulling 2 or 3 millimeters off center during that window. I always thought you just tack it, braze it, done. He pulls out a notebook with temp readings from frames he built in 1998 and shows me how he clamps the rear triangle in a fixture until the whole thing sits under 200 degrees. I tried it on a 1983 Trek I was rebuilding for a customer, let it cool in the jig overnight instead of pulling it at 400 like I usually do, and the dropout spacing came out dead on 130 with no cold setting needed. That one change took maybe 10 minutes of waiting and saved me an hour of realigning. Has anyone else heard the 200 degree number, or does it vary by builder? Because now I'm second guessing how I've been doing every frame this whole time.