The wheels are here, aren't they small! The castings look good, starting the machining before weekend and in meantime making the counter weights and crankpins etc.
Machine by griping the tyre, running as true as the casting allows, then drilling and boring the centre, reversing on a mandrill, and fixing with superglue and pressure from a live centre with a cup.
The tyre is turned flat.and the root radius machined in one op,, then the wheel is removed after machining the flange and front face, a spot of heat breaks the glue.
Each wheel in turn, and then grip on flat tyre to machine the back, with recess to expose the spokes.
Then all are re-mounted one by one on the mandrill and the taper is cut on locked settings for all four,
Then all are cleaned around the back of the spokes. Whilst on the mandrill the tyre can be polished to high finish, and by gripping on the flange the boss can be finished with a satin surface.
The back of the wheel is not flat, a raised central boss is know left to prevent running on the frames. Axles are made to just the bored holes and pressed on with loctite.....
As the wheels are cast iron, slow lathe speed should be used with carbide tools or inserts.
i do not turn between centres, it requires pre fitted drop in bearings and this method with care gives great accuracy. and ease of assembly and quartering by a simple jig.
The vital point is that all wheels must be identical diameter. no tolerances. the same or the wheels will not pull.
Edited by bertiedog, 18 April 2018 - 22:02 .