Rotating Ball nut

[Jonathan]

Add at least two more vertical pieces on either side of the frame to better support the rails - it will make a huge difference.

Is that a 12Nm motor on Y?!

I use rotating nuts on 2m long RM2510 ballscrews on my machine and they work very well. I posted about the design and making them here:
http://www.mycncuk.com/forums/linear...ign-ideas.html

If you're after the simplest design, then that's not it. My priorities with the latest designs in that thread were to make the moment of inertia of the rotating parts as low as possible, to get good acceleration, and to make the assembly compact. This means I get good performance with just 3 or 4NM Nema 24 stepper motors, which saves a lot of money on the motors and drivers.

I've not seen the one you have a picture of before. Where did you find it? It's nice and compact, but the problem with putting the ballnut through the bearings is you need much bigger bearings and a larger diameter shaft, both of which make the moment of inertia substantially greater since it is proportional to the diameter of the parts to the power 4.

[Fivetide]

Holey Shit thats huge !!! I WANT ONE I WANT ONE !!