After far too many attempts I am almost there with the return cranks. Both my hand filing and my measuring proved inept, when on one of the attempts I managed to forget to take account of the radius of the big end and the whole thing came out a good 3mm too short. To be fair even if it had been the right length, it looked awful too.

For the next and hopefully last attempt I drilled all the holes and made sure that they would centre over each other on the two layers then I soldered one end together and before adding the bolts I carefully marked up the shape of the crank where it transitioned from the big end to the smaller end.

Next, I gripped the crank at an angle in the mill vice (using a parallel to ensure that the edge line was level and then milled down to my marked line on either side.

After some cleaning up and going around the raw edges with more solder to ensure that they remain as pairs I fitted the retaining bolts. I did manage to rescue all eight from a previous iteration then I dropped three of them as I was fitting them to the new cranks.

After coffee and while typing this post, I decided to have another look to see if I could see any of them and was pleasantly surprised to find two of them. They are so small that I didn’t expect to see them again.