Originally Posted by scarlson

The threads were ok, though. I wasn't really repairing threads. A helicoil is only really useful for threads. And it might not work in a stripped canti post either, because the walls of the post are so thin.

The problem on this bike was that the post that the brake pivots on had been cut short, leaving only a stub with a few threads. My job was to add some length to it, so a brake could fit on it again. I did this by screwing a small threaded stud into the threaded hole in the remaining stub, then threading on a piece of an old cantilever post, and finally brazing everything together using silver. This created a nice robust repair, stronger than the original.

It could also have been done with JB Weld instead of brazing, or even with nothing at all - just a long m6x1 bolt to mount the brake arm with the missing piece screwed on in the middle. But brazed-on, this is a sort of "gold standard" repair, and was pretty interesting/fun to think up and do.