I’m currently in the (long) process of fixing up Mom’s 1960s Peugeot PX-10. I want to give it a proper paint job, so I’ve been working on removing everything from the frame. Getting the crank arms off has been the hardest part. First, I needed to buy a special extractor to get the Stronglight cranks off (it has to be exactly 23.35mm, a ridiculously non-standard size). Then, I had to figure out how to get a broken-off bolt out of the the axle. Turns out the latter of these two tasks is easier than expected!
I bought a bolt extraction kit from Lowes and got it right out! Here’s how it works: You drill a small pilot hole right in the middle of the broken-off bolt to be extracted. Then, you insert the extraction bit in the hole and turn it counter-clockwise with a wrench. The bit is reverse-threaded, so the turning effort simultaneously unscrews the problem bolt while simultaneously driving the bit further into the hole. Neat!