3D models are all very well and good, but there are practical aspects to fitting a gear train inside an existing model. In particular, Percy received a bunch of weight in the boiler and saddle tanks. Who knows if the theoretical drive will actually fit?
In about 20 minutes, the filament printer made rough approximations of the shapes of the two drive trains I had sketched in OnShape. Rough because the support removal was such a nuisance I gave up and left some on. Then, I took Percy apart yet again to see what was inside, discovering some awful corrosion on one of the wheels.
Sure enough, neither of the options fit as well as one would hope, with the short version being slightly better than the long one. After an evening of puzzling with the 3D model, I came up with a plan to angle the short gear train by ten degrees to clear a big wad of lead that sticks into the motor cavity. Ten minutes later, I had a mock gear box and motor assembly to test inside Percy’s boiler.
This shape is going to need a replacement rear frame section. However, as I still have the original 3D model, the hardest part of making that will be matching the colour!
Pembroke:87 