Originally Posted by
grumpus
Use some strong thread looped over some coils a few times and tightened like a tourniquet using e.g. Allen keys. The thread has to be thin enough that the shaft will still fit, which may preclude use of string or twine. When you've reinstalled everything just cut the thread.
Many thanks to
grumpus , whose tip pointed me in the right direction. I used a length of 13mm Velox rim tape, which was flat enough to be out of the way of the shaft. I put a length through the spring, compressed the spring in a vise, and then tightened and tied the rim tape. The spring was obviously curved when I released it from the vise, but it was no problem slipping it onto the shaft. After that, it took me a couple minutes to get all the little bits on the shaft, securely. Next up will be adjusting the arms.