I have now moved the spindle mount lower onto the backing plate, how does this look?:

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I have done a bit more digging into why people within the Joe's community have moved away from ball screws to R&P, the reasoning appears to be about speed, ease of assembly / maintenace and price more than anything. Looking at the pricing of C7 leadscrews on BST Automation they seem to be cheaper than using the CNC routerparts rack and pinion system (although the postage costs are about as much as the screws!) - I'm confused as to which way to go, any suggestions please? Would I be looking at 2010 for the longest axis, it will be 1600mm long? This comes out around 1000RPM critical speed - is this too low?

All help gratefully received.

Cheers