I started a thread about this in the user diaries but it had no interest. I've now made more progress so am putting it here, I hope that is ok.
I've made a few iterations of alternators over the years which you can find on here. I've taken a break from them for a while, but hopefully what I'm working on now is the best I've made so far.
I recently got two copies of this part laser cut out of 8mm mild steel:
They came out really well. Cost was £15 each. I can share the CAD file with anyone interested.
I designed these parts to be a perfect fit for a car wheel bearing that I have. The rotor attaches to the bearing fine, but working out how to attach this bearing to the rest of the structure was a big problem for me for a long time, so I'm glad I have this solved now.
It is a bearing from a Vauxhall Astra MK4. You can buy brand new ones on ebay for around £35. Mine came from a scrap pile at the local auto mechanics, but I do need another for the other rotor that I will get at some point.
Here is the bearing attached to the plate, with six 12mm threaded rods to support the rest of the structure.
Next, my rotor consists of a car brake disc with 24 neos epoxied on:
(Continued on next post)