Thanks Hiorth! Here come some more pics about lathe!
To clamp the hub from other side i turned some adaptor.
Now this prop is really short.
Test the rotor fitting to props hub.
I managed to make the spinner from one part 3D printed with some support.
I plan to fill this with epoxy. We come back later to this.
First i have to epoxy the rotor magnets. You need to tight both ends of the rotor. For the inner part i use a rubber ring, R-32 ,ID 50, SD 3.55mm which i place inside the rotor and push it as near as possible to the rim of the rotor. Its a little big, so it sits very strong. This is the 4th rotor i am making, and they all worked perfect at that place. Use aceton or isopropanol to take away grease from the rubber.
Other end is also rather simple, i used some rings made of solder bobbins which i mount with tape to the rotors open end. This time i had no bobbin over, so i printed the part.
For this is use a ring of outer diameter 63mm, ID 53 with a kind of emergency reservoir.
This reservoir allows you to not overfill the rotor with epoxy, if you overfill the abandon epoxy will run into the reservoir.
I used 25ml without overfilling (hope it was enough).
Put the tip of the syringe into the middle of the rotor and carefully dose the epoxy ml by ml while rotating at more than 1000RPM. In the end you should not see any fragmented reflexions. Never stop the rotation! If you have a power outage or stop, be very careful, make sure no epoxy dripped over the barriers and start from low RPM, otherwise the epoxy might get on you! For this reason i do not mount the axle while epoxying. If you stop, the epoxy drips on the axle and it will spray if rotated again. Avoid anything which could cause a mess.
I use 40minute pot time epoxy.
I let it run at 1250RPM two hours. When it starts to gel i reduce to 300RPM or so and let it run for several hours. If you want to speed up by warming, you have to be very very careful. The tape which tightens and holds the ring is temperature sensible and can get loose if heated by e.g. hair dryer. The epoxy will be sprayed over you and everything around giving everything a new finish. If this ever happens to you, dont panic. Let the epoxy drips where they are, do not try to get it out of your hair or cloth, you will only worsen things. Let it just where it is until its almost hardened. Than brush it away. So i will not warm it any more, but just wait and listen to the howling lathe.
i am happy!