For the miniature traction engine wheels there are a pair of front wheels and a pair of rear wheels. In both cases I’ve followed a similar construction method.
Rear Wheels
The rear wheels are only 97mm OD, hence my initial thought was to buy some thick walled 4 inch diameter pipe, but I just could not find any. I bought 100mm mild steel round bar, 2 off pieces at 1 inch long, I then had to machine the rims roughly to size.
Machining the treads at 7° to the wheel was tricky but rewarding. Machining a pair of wheels with handed angles at 7 degrees was tricky.
The hubs need 8 slots machined on each face. The slots are 4mm wide and arranged so that the spokes on one side of the hub fit between the spokes on the other side.
The next stage was to make the spokes and then build the wheel up.
Front Wheels
Machining the front wheel rims. The front wheel rims were machined from 70mm OD mild steel round bar.
The Brass hubs took some time due to their size and precision needed. I messed up a few parts before getting this correct.
Then another set of 12 spokes for each wheel. Once the front wheels were assembled and soldered the rigidity of the assembly increased significantly.
The final operation for all of the wheels was to face the hubs on both sides, this give me a finished flat surface and will allow the hub caps to be bolted in place.
Set of Four Wheels
Finally a set of Miniature Traction Engine Wheels.
To put the wheels into scale they are sitting on a sheet of A4 paper.
The traction engine in elevation fits onto a sheet of A4 paper.
There are a total of 64 parts and 60 rivets required to make the 4 wheels. Along with the creation of a lot of swarf.
This feels like quite a significant step on the road to building the traction engine.