CR-10 Extruder Knob - filled

I really like the original knob shape but having fited a filament filter on the extruder input wanted to stop things dropping in to the gap between the motor hob gear and idler; seemed silly to stop dust getting in on the filament but then leave a length exposed to allow re-contamination.
I filled the centre of the handle in and then extracted a shaped from each aperture keep the aesthetics and allow it to print nicely without supports