As you saw, the disc brake caliper wouldn’t clear, so I had to figure out a way to dimple the stays without affecting the outside of the tubes. @RustySprockets
offered a genius solution. Get a harbor freight pair of bolt cutters and modify them. So, for $20 I got a set. At work, I cut a piece of 3/4” rolled stock and piece of HREW pipe, then cut the pipe in half.
I took them home and ground them smooth because I didn’t want sharp edges affecting the bike frame’s metal.
I cut some chunks out of the bolt cutters (and the cutting edges) and welded the two pieces on either end. Took them home and smoothed them out again. This is it opened up.
And closed. I made it so it wouldn’t clamp completely because I worried about hurting the frame.
So I went back to work and had one of my guys fire up the torch (literally), heat the metal up, and I crimped it. The metal was almost gooey, and crimped super easy.
I got it home for closer inspection. Here’s the crimped side and the drive side for comparison.
What I won’t know for a week or so is if it actually worked. The wheel is awaiting spokes. My spoke guy said done this weekend and shipped on Monday. So I’ll get that rear wheel laced up, mounted with the brake, then I’ll test the fit and make adjustments. Meanwhile I can work on smoothing out the frame’s metal. There is a good bit of rust pitting I need to smooth out.