WEEK 2: Rolling Rotor Housing (too small) and Test Fitting, Lathe Crankshaft Coupling, Rotor End Cap Design for CNC

This week, I finished rolling out my rotor housing with the metal roller at school. I am fairly happy with how it has turned out, but by design, there are 2 sort of flat ends.
I then went to fit 14 of the magnets in, only to find out the rotor was somehow too small. This really frustrated me as I had spent so long on perfecting the design and even left a 4mm oversize in case it ended up too small, but it still at least a 5mm gap.

I have to choose to stick with it now as the rotor cut took me a very long time in the holidays and it would not be worth cutting it out again. I had to think hard about why it ended up too small, and I managed to come up with a theory of how the steel rolls physically.

I had calculated my measurements from the (inner diameter of the rotor * pi), to calculate the length of steel I needed to roll. I thought this would be the same for when I roll the 3mm flat steel, but I have now realised that when you roll the steel, the inner compresses and the outside stretches slightly. This means the actual calculated diameter should have been approximately halfway in the 3mm steel, so effectively 1.5mm + 1.5mm larger diameter than I had calculated. This would make the rotor over 9mm smaller than needed, which would make sense in how my rotor housing turned out.

But I will have to make do with the current state and maybe weld a filler in between the gap to complete the rotor housing.

I also worked on lathing/turning my crankshaft coupling down to fit into the rotor end cap which I am preparing to cut out next week.

I decided on taking all the old teeth off to create a cylindrical coupling of 50mm OD to slot into the rotor end cap and be welded in.