Wren list a 55mm wheel that would be suitable for the Ram 500 and Dieter Albisser (jetmax.ch) makes a number of wheels including 66mm size which is the same size as the Ram 750 and 1000. Any wheel you buy will be better bought as a casting unbored and then bored out and ground on the outside to fit your engine. If you buy it machined you need to be very careful that it will be a tight fit on the shaft and fit the NGV with the right clearance. Inconel 713 is a very tough material but it can be bored on a Boxford/Myford lathe run slowly with the correct drills using oil and using a sharp carbide boring tool to finish to size. You will need to make a jig to hold the wheel nicely central and which holds the wheel on the flange that the blades sit on.


John