Summary

Drop in replacement for Mk2 / Mk3 ultimaker 3mm filament feeder.
Wheel2 is my first version.
Wheel3 has larger holes and a support cylinder in the center.

Instructions

I printed at 0.2mm using my Ultimaker and Cura.
Used gold PLA at 210degreesC

Derived the gear+holes from MoonCactus and added the 3mm thick hex boss to replace the washer used in the wooden version. The boss clamps between the hex nut and 'acorn' nut so the gear dosn't wobble like the wood one. (I am using the Mk 3 knurled drive : https://shop.ultimaker.com/en/parts-and-upgrades/knurled-bolt-kit-version-3.html )

I printed 'wheel2' without support and the centre 8mm hole took a few layers to form properly and needed tidying with a knife - try with cura's support option, or print 'wheel3' and snap out the support cylinder after print.

This gear runs better than the wood one - possibly because it is slightly smaller diameter accross the teeth tips - the teeth root diameter is the same as the wooden ultimaker laser cut unit. I havn't checked the STL/Scad data, but it could just be due to the rounding of the tips by the filament process.

The small laser cut plastic gear has small root radi as a result of the laser process, whereas the wood large gear has sharp tooth tips. They seem to have been designed witout any root clearance, which is not advised for this reason (and others)!

Ultimaker Stock Large feeder gear