One of the key components in the Stain Dipper Machine is the top pulley assembly.  It is crucial that it normalizes the unspooling location of the cable so it does not put lateral forces on the slider rod below.  To this end, we designed and created 3 components out of UHMW (Ultra High Molecular Weight Polyethylene).  It’s a nice plastic to work with, and super tough.  It cuts like butter but has a lot of strength too.  This is a 10mm hardened shaft with two bearings pressed into the UHMW.

Here is a picture of the 3D model.  As you can see I haven’t trimmed the shaft yet.