With the original permanent magnet assembly removed, the next job was to make a platform for mounting the electronics and electromagnets.
For a first prototype, I used a piece of MDF, which would be easy to machine and shape, and has fairly good dimensional stability against environmental changes.
This was turned to a round plate (of around 140mm diameter) on the lathe. I then put a chuck in the tailstock, and used a selection of Forstner bits to drill out the internal steps required to mate with the resistance unit and support the bearing. I also needed to remove some material to fit around the body of the resistance unit, and drill the holes for the locating lug & mounting screws .
Once the overall shaping was complete I sealed all the edges with some diluted PVA glue. While probably not as good as a dedicated “MDF sealer” this will hopefully prevent any swelling from water ingress on the bare faces.
The plate was then attached to the resistance unit with the original self tapping torx screws.
I’m quite happy with the resulting fit. Assuming this approach works, I’d like to 3D print the final assembly, so have been taking detailed measurements along the way, and working on a model in OpenSCAD.
Next post should hopefully get back to some electronics ;) Thanks for reading!