Gear Retainer for Gravity Spool Holder

I got tired of my ¾ empty roll of filament slipping down the ramp, which defeats the purpose of the auto-rewind part of the spool holder.        

The parts slip onto the left and right frames and ensure that the spool gears are always meshed tightly with the frame. They can be easily removed at any time to replace or reload a spool.

There is a 1mm gap between the gear and the retainer, so there shouldn't be any wear during normal use.

Recommended print settings:
Supports: None
Layer Height: Any
Material: Any rigid material should work.