I am so pleased to see people address weight and geometric rigidity and the effects of mass properties on stepper size and life span.

IMO, weight that does not do any work is bad engineering and the domino effect elsewhere in the system is never positive.

I am about to build a Joes2006 but have tossed the MDF aside, choosing instead to build the first iteration entirely out of Apple Plywood (Baltic specs-lower costs and available in 4' by 8' sheets)

Were I not in so much of a rush to start cutting parts for my prototype designs, I'd reverse engineer the gantry and Z-axis fixture around composites of vacuum bagged low density structural foam cores and multiple plies of bidirectional fiberglass.

Since this is my first attempt at building and using a CNC router, I'll stick to the basic design and gain some experience first.

Still, on the basis of 30 years as a mechanical designer, I think the questions being addressed here are valid and pleased to see the responses.

L.J.