Bike From Scratch

Frustrating and slow to backwards progress was the name of the game for two of us today. I brazed up the first part of my bi-laminate lugs. This went pretty well and all seemed good. I started putting the frame together in the fixture and it looked well. I noticed Doug making faces at it so I asked again what he thought and if I should ditch it and just fillet braze the frame. For the first time since we started this endeavor he changed his answer a bit and since I was already nervous I pushed the issue. My line of reasoning was basically could I do it by myself or would Doug have to take the torch and bail me out. After confirming we decided that there would probably be quite a bit of bailing out and I get the feeling that Doug wasn’t exactly sure how to handle the bi-laminate with tubes smaller than the lug opening. I suspect this is one of those things he would figure out on the fly, but would be made more difficult trying to explain to me while I was brazing and he was doing the figuring out.

The beginning of the end for the head tube.

So we decided to switch, the existing head tube went in a box, and I pulled out the head tube I brought with me and cut it to length. We had to switch the seat post I had as well to an externally butted tube. The tube that was already brazed to my bottom bracket needed a lug at the top tube / seat tube junction to function correctly. I also had the option of creating a sleeve but the time and work this would take felt overwhelming and I decided to go with the externally butted sleeve.

So we had to remove the existing seat tube from the bottom bracket. This was done by putting a bunch of scrap parts (bottom bracket shells) on a wire loop and inserting the loop through the bottom bracket to add weight. We then heated the whole joint and waited for the shell to fall off. One of my classmates and I didn’t have much luck getting this to work but Doug came back to the shop and made the magic happen. It was good to learn how to undo a joint. So I guess there was a positive side to the exercise.

I brazed the new tube in by myself and that went pretty well. I was on a mission to at least be back where I started in the morning. I feel a lot better about silver brazing. I also did a practice fillet by myself. I learned some things about speed control and when to fill. This one looked no so great but had some good sections towards the end. I think I’ll do a bit better on the next practice one which I hope to do in the morning.

The other thing I did today was align my fork blades. This took out some of the extreme problems that I mentioned yesterday. It’s still a bit crooked but can be fixed with a smaller amount of filing than I was anticipating, so all is not lost.