I read through the "Make your gantry rock solid!" thread where a "moving knot" design like those cable systems in drafting tables and pocket doors is described. Judging from the responses in that thread and having seen various "high end" fences and such that use a similar design, I'm willing to believe it will work.
One could obviously use the design to simply reduce the effect of racking, but I'm wonderng has anyone out there used such a design as the primary linear motion system. If you had a ~4" diameter "winch" you could get about 1' of cable for each wrap around the winch. If you use your stepper to directly drive the winch, and the cables are set up in a moving knot configuration, it would seem like you could get all the benefits of a double leadscrew set up without having to deal with screw whip.
Of course there may be interesting backlash issues and you may need to gear down the stepper to get a decent resolution, and half a dozen other things I haven't thought of, but it should work shouldn't it?
I'm not asking because I think it is going to be cheap, I'm curious why I haven't seen it discussed before. Or has it been and my search-fu is just weak?