Posted by duncan webster on 07/01/2023 22:46:43:
Why does it need to be machined on the rim, the real ones weren't. You can machine the boss on your milling machine
Maybe because mould shift does not scale very well, having the two halves 1mm out of line on a 10ft flywheel would be fine but not so good on a 9" one. If you file it away you end up with out of round and maybe a bit of cupping of the casting where it will notice on a small engine but not on something large and moving at less rpm.
I suppose one could put the hole in first and then set the flywheel up to rotate and spend your time filing off the machining allowances (no machining allowance on full size) and constantly checking for high spots or wobble and eventually end up with a true running wheel to size but I expect most don't want to go down that route. Certainly George Gentry and Exactus both opted for machined flywheels and Mr Gentry even farmed it out to a workshop with a larger lathe,
Edited By JasonB on 08/01/2023 08:05:17