Microextruder for geared stepper

This is an idea I've been working on in my head for several months and dozens of revisions. I finally decided to get something into the computer and post it, and gave myself 24 hours to do it. This is a very small extruder block (it should be smaller than Brut) that has a spring-tensioned bearing idler like Wade's and a single tightening screw like the Mk5 Plastruder. It is designed to be used with a planetary gear stepper like this one, and Mk5 drive gear with the hole drilled out to 8mm to fit the gearbox shaft. It uses two M3x35mm screws, two M4x50mm screws, one M8 bolt or rod about 35mm long, one 608 bearing, and a couple of nuts and washers to match these. One end is meant to hold a nut screwed onto a PTFE tube (which could be a bowden cable, or if it runs the other direction, it could just be a feed tube) and the other end is meant to accept a groove-mount insulator, so the same block can be used as a bowden or carriage-mounted extruder with no extra mountings.

In the included