The description on that ballscrew set doesn't quite add up to me.
" By adding Double Ballnuts to our ball screws we have doubled the accuracy to the kits"
I am not an expert, but adding a second ballnut doesn't improve the accuracy at all.
" Because the Double Nut ball screw is more efficient. You are able to run at NEMA 34 motor on the Z -axis giving you more power that you need for the Z axis"
I am pretty confident the opposite is true. Double ballnuts are going to have preload, which will increase friction and make them less efficient than a single nut. I know for a fact that the Z axis can be run with a 16mm single nut with a nema 23 motor, so I am not sure what they are saying about a double nut being needed to be able to use a nema 34 that you need for the Z.
> .0015 to 0.005″ Accuracy / Backlash
I don't know why they are referring to accuracy and backlash as the same, but either way 0.005" on either is definitely on the high side. Their description just gives me the willies.