Huey edge slide.

After 3 versions the edgeslide should be stable both mechanical and version wise.
http://youtu.be/0r5rYepdS4I
I initially had rough travel on one axis and couldn't really pin down the cause. Using dual bearings and moving the belt attchment to be inline with the shaft may have helped but I can't say for certain.
http://nerdipedia.com/tiki-index.php?page=huey