That sound good Hood.
Only possible problem that I see is the belt being the weak link in that all of the cutting/tooling pressure during anX axis move will be against the belt instead of the "Metal to Metal" contact in a normal gear arrangement. Maybe use a brake of sorts ?
Should be fine for lighter cuts in softer matl though.
RC
Timing belts seem to be very hardy things, when I was setting the servos on the lathe up I was testing the stiffness of the settings by putting a long bar on the ballscrew pulley and watching for encoder movement in the software. If I could feel movement on the bar the encoder was twitching, I could set the stiffness such that the only time I felt any movement in the bar was when I applied so much pressure that the drive faulted.
This amazed me at how good timing belts were, I thought that there must be quite a bit of give in them, after all they are made of a fairly soft material but amazingly there seemed to be no noticeable movement at all.
Hood