Example Y motion bearing

Uploading the example as I have simply seen too many claims that "plastic bushings do not work", when using unsuited designs. This is one bit of folklore with with which I do not agree.

You have to use a design appropriate to the task, and means of fabrication.

I am not inventing anything, here. These are old ideas from examples I saw very long ago (though probably not made of plastic). Too far back to recall the source.

Most 3D FDM printers are simply not accurate enough to fabricate bearings that call for close tolerance. But you can achieve close tolerance in the end with careful design.

There are two design tricks here.

First, there are three lines of contact along the rod. Three points is sufficient to force exact placement of the rod within the bearing. As the two upper points are offset, the weight of the build plate is also forcing exact placement.

Second, the slot/plug in the bottom allows fabrication with less precision. When assembled, a hand clamp (or any