Framebuilding with Dave Bohm: Days 8 and 9

01 Apr 2015 Framebuilding

The past two days were dedicated to brazing up the main triangle of the frame. I had to cut the main tubes to length, which was nerve-wracking because Dave ordered a special top tube for my bike. If I cut this tube too short I wouldn’t have a backup tube with the same thin walls. With just one chance to get this right, I spent way too much time rechecking my measurements and second-guessing myself.

Before I knew what hit me Tuesday was almost over. Only three days left to get this thing built. Cooper had brazed his main triangle together and I was still prepping everything. I was getting worried I wouldn’t finish in time.

I had trouble sleeping Tuesday night. What if I didn’t finish? Do I know someone with an oxy acetylene setup? Will I have to go buy an oxy acetylene setup when I get home just to add some necessary braze ons? What braze ons should I put on the bike? Will the bike come together as I planned? So many troubling questions that only a bike geek with no real problems in life would get worried about.

As Wednesday progressed however things came together just fine. I set up the main components in the Anvil fixture, tacked the lug sleeves to the head tube and seat tube, fillet brazed the sleeves out of the fixture, cleaned and filed the fillets, cleaned everything (always with the cleaning), put the fluxed frame back in the fixture, tacked the sleeves to the top tube and tacked the down tube to the BB shell and head tube sleeve, removed the delicate triangle, checked the triangle for alignment, added more flux to all joints, silver brazed all joints, cleaned off the flux, checked the frame for alignment post-braze, cleaned the lug shorelines, ate lunch and dinner during the process, and hopped in bed at 9:30pm. Whew!

The obligatory frame in the fixture shot. Everything checked out, so it was time to start the brazing sequence.

After tacking the sleeves to the top tube, I bronze brazed the sleeves. Well, I brazed one of the sleeves and Dave brazed the other. Can you tell who knows what he's doing? — After tacking the sleeves to the top tube, I bronze brazed the sleeves. Well, I brazed one of the sleeves and Dave brazed the other. Can you tell who knows what he’s doing?

After some love from the files and sandpaper, the seat tube sleeve is looking handsome.

Dave gives Cooper some sage brazing advice while Cooper does the final fillet brazing session on his bottom bracket.

My bottom bracket turned out the best out of the four joints I Brazed to create the front triangle.

Dave's alignment system relies on the head tube to check for twist between it and the seat tube. In my case the frame was nearly spot on. That's good because there's not much one can do at this point. — Dave’s alignment system relies on the head tube to check for twist between it and the seat tube. In my case the frame was nearly spot on. That’s good because there’s not much one can do at this point.