Anybody ever seen a flying lead nut like My Z-axis? I’ve searched, and the closest I have come is a power steering boost gear setup. More importantly, is it useful ? It works well, and it keeps the motor at the gantry level, instead of teetering atop a tall Z-axis. Also the screw becomes a rigid structural element. What say you all? Anything to see here? Please let me know what you think.
I think an error occurred when I tried to play the video.
This is a common arrangement on long rods, as turning the nut has much lower inertia than a long threaded rod. Some steppers do have the nut inside their shaft (threaded shaft).
This is a small one though https://www.sparkfun.com/products/10848
@Miguel_Sanchez
That is what it reminded me of. The motors where the threaded rod goes right through the motor.
Reminds me of one of the products at bell-everman.
http://www.bell-everman.com/products/actuators/servonut-power-module
I love this concept !
Thanks for sharing and the links 
@Marcus_Gutmann thanks for the clip. I wonder why you don’t see this more often? What are the drawbacks?
Still have to find such kind of nuts for 20xx or 25xx ballscrews…
@Jeremie_Tarot there are two choices: http://www.linearmotiontips.com/long-travel-vs-high-speed-part-2/
Miguel Your links are great. Still this technique seems under utilized to me. Do you know what the drawbacks are? There must be something I am missing. Seems too simple.
@Miguel_Sanchez seconding @Jerry_Helm about your links … And asking myself exactly the same questions !?
If superior cost may be due to under usage, I hardly see how rotating nuts and assemblies can be that much complex to justify this confidential spreading ??
Anyway, think I’ll investigate (read find actual prices) further because this has seeded ideas I’d like to grow for a 4’x8’ or 5’x10 ballscrew driven design…