BUILDING A

METRIC MINNIE

Part 12 by Franco Pucci

Back end part 3 and rear wheels

Machining the flywheel. This was machined form a solid piece of cast iron, and I promise, it was a laborious process.
Holes were milled at the wide and narrow parts of the spokes before machining away the rest to form the spokes.
Almost done (a day of machining later).
Done - thank goodness.
Starting the gear change lever - material, stainless steel.


The completed gear change lever.
The gear change lever assembly.
Making a start on the rear wheel spokes (with my other boss looking rather bored and of course sleeping on top of my tools) the wheel blanks were machined at the same time as the front wheels. Spokes were as yet unbent.
My spoke bending calibrated measuring jig…the wheel rim is mounted on a jig with a centre spigot to keep the wheel hub centralized for the spoke bending. If the wheel rim starts lifting when spokes are fitted - correct this as you go otherwise the runout (wobble) will be very difficult to correct when all the spokes are fitted.
I made a jig to ensure that all the spoke mounting holes were drilled at the same radius in the wheel rims.
Placing the bent spokes both to check the bends, as well as the position, prior to drilling the holes.
The spokes all fitted and the wheels were checked for runout. Once I was happy with that, I started on the strakes. The holes in the wheel rim were drilled in position using a rotary table and drill press. The strakes were manufactured from aluminium and given a little twist to conform to the wheel rim.
All the strakes fitted and riveted.



Rear wheels fitted - and for the first time I could see if the boiler was horizontal or not - thank goodness it was perfect.
Brass slug marked up to machine the rear wheel hubs.
Machined rear wheel hub prio to de-burring and polishing. Next I would machine the shaft hole and tap all the holes (M2 - not sure what BA that is).


Part one here  Part two  Part three  Part four  Part five  Part six  Part seven  Part eight 

Part nine  Part 10   Part 11  Part 12  Part 13  Part 14  Part 15