I have read that entire blog and unfortunately nothing about removing the arm shaft. I believe that the one I have is a 15-91 because it has a potted motor with a worm drive, no belts. It is hard to see in the picture, but the bed has a big chip in it and the finish is so fragile that it just flakes off. Since I have already removed every other part for a deep cleaning, I don't want to only do a 95% job. A new paint job will last a lifetime. When I am done polishing all the tiny screws and parts, I will post a picture.