Ender 3 Pro Spool Separator

My **Ender 3 Pro**'s extruder arm got a nasty groove cut into it from years of pulling filament through at an awkward angle. I printed up a replacement to tide me over until my aluminum upgrade kit arrives. Unfortunately, there's either too much give in the PLA or the opening for the filament is too coarse, because my first print with it suffered from severe under-extrusion. I tried putting some washers under the spring to give it a little more tension, but it was no use. The only way I could make it work was to orient the spool in such a way the filament fed directly into the extruder, no turns or curves. I had an old USB microscope stand that did the job well enough, but the next day I decided to make use of the **Ender**'s included spool arm.

This is designed with 20mm extrusion in mind, along with M5x12 bolts and t-nuts as that's what the spool arm is made for, but if you were feeling adventurous, you could scale it up to 25mm/1inch extrusion and 1/4-20" or M6 hardware should w