[spoiledbrat]

This is not a new concept, just my interpretation of it.
It is a Rhino rendering of two 5/8 " ballnuts. Both screw into a threaded collar, and the two collars are shouldered such that they slide into one another. The inner collar would be bearing-bronze, and the outer either aluminum or steel. The inner and outer collars have a key and keyway to inhibit any rotary motion between the two. There is a spring coil within the two, to provide between 20 and 80 lbs of preload pressure. As I understand it, the spring will enable the nut to transition across the tight spots along the screw without mechanical failure, and provide the proper amount of preload to the system.
Now, we can all imagine the gymnastics required to mount the complete unit onto the screw...
The two would have to be compressed together to the proper pressure, with a cardboard or plastic tube within so as not to lose the balls. The first would thread no problem; some relief or more pressure may be necessary to align the second ballnut of the system into the proper lead chanel.
This design is not the most "adjustable", but should offer preload in a few ranges with one kind of spring, and the spring could be changed out for more.
I am leaning toward using some form of locktight for the 15/16" threads on the actual ballnut.

I AM NOT A MACHINIST. I do have a friend that will make these for me, if they are right. Does anyone see anything wrong with, or improvements to, the basic design?
If anyone knows where I can find an inexpensive coupling (<$40) that will do the same thing, I will just do that. There is no sense reinventing the wheel on EVERYTHING.

Thank you in advance, everyone. This is the best thing to happen to the internet yet.
:withstupi