I’m unemployed, so I thought I’d spend some time making a new bike for myself. I had this set of Brompton-sized wheels, with the rear laced to a Bendix coaster brake, so those will be the wheels. I have a lot of scrap and left over straight gauge tubing as well. So here goes.
I usually start with a big drawing. Here I have sorted through what I have and am figuring out what tubes to use for what. Back when tubing was a lot cheaper, whenever I’d order some straight gauge, I’d add a random tube or two because shipping was the same.
That done, I started in rough cutting and cleaning the tubes.
My brazing is rough. I haven’t built a bike for more than two years. Also, my friend got a new torch and it’s taking some getting used to. But I’m trying to focus on smaller fillets, going slower.
Here the ST is already joined to the BB. So is the DT. I did that joint in a similar way to what you see here, using tube blocks clamped down on the metal table to keep things aligned.
The chain stays are brazed into a couple of sockets I’d already brazed onto the BB. This technique makes up for my lack of a frame jig by allowing me to position the chain stays and have them somewhat stay put for brazing. Despite that it took a good deal of yanking to get the whole thing straight.
I mentioned this whole thing is kind of improvisational. So today I spent some time thinking about how the racks are going to be. The rear won’t really have seat stays. The brazed-on rack is going to do that job.
So these aluminum rods are just helping me visualize.
And this one is helping me see where the chain needs to go. I have built this style of bike a couple times, and once I put one of the rack supports right where the chain wanted to be.
I was going to braze this whole thing onto the frame but I paused. My fixturing situation is not great, and I don’t want to fuck this up. So I will work on something more rigid than what I have now, and return to it next week.
What remains is something to support the rear, because it’s too weak as it is, and something under the front rack as well. Then braze-ons for a chain guard and of course the head badge or some sort of marker.
I have these Ns which I tried stamping, but the stamps deform the metal - which might be OK. Not sure yet.
Put some little fenders on there to see how they fit. They’re just balancing on the tires - rest assured, once installed, fender lines will be 100.
I was going to add a support at the front but ran out of time. All that remains after that is some chain case braze ons and to cut the seat tube slot. I’ve never done a straight one. Will this be the first time?
