This is a long page not because the part was especially difficult, but because of a major problem part way through that caused me to have to re-make the part. I decided it was important to let others know about the problem I encountered so I’ve included that in this documentation.
The impeller started life as a 125mm diameter by 300mm piece of Aluminum 7075-T6. I bought a stick of this long enough to make the front cover, crankcase, rear seal plate, air guide, impeller, and a few fixtures. The diameter was needed to accommodate the crankcase so I did end up wasting a little material on the other parts.
I’ve been thinking recently about the crankshaft construction on the Hodgson Radial. I’ve never really been happy with the 5-piece construction and I’m thinking of changing it to a 3-piece crank where the crank cheeks (counterweights) are integral with the front and rear crankshaft sections. The main journal would then be clamped by splitting the upper portion of the crank cheek and using a compression bolt to retain the journal.