Low cost 0 backlash transmission - Ball bearing + trapezoidal screw

[LabSkis]

Hello,

Despite some search, I haven't found anything on this forum about this technique described (in french) here: http://cncloisirs.com/Construction/E...ntVictorSendas
Here is a picture from this site which can help you to understand:




It seems very simple, a ball bearing rolling on a trapezoidal screw and quite efficient in terms of backlash reduction & transmission without friction.

Have any of you tested this technique? What are the feedbacks?
I am wondering what is this "nut" in which the ball bearing is maintained?

Thanks for your answers!