Recently I have seen homemade ball screw video and I send my drawing about this. Any opinnion with more details will be appreciated a lot.
Here is link:
http://www.youtube.com/watch?v=wzpujoPgOLo]home made ball screw - YouTube
and drawing is .dxf attachment
It was suggested sometime ago by Greybeard in this thread:
A different (better) kind of screw
The problem is fairly obvious from the video; For a ball screw to work well the threads (internal and external) have to be very smooth and hard. If they are not the surfaces will quickly deteriorate and/or the friction willbe too high to be of any use.