Quick Swap Dual and Single Idler lever for Core One (For brittle filaments)

I designed this because I was trying to use Polymaker Fiberon ASA CF-08, and as polymaker says, it is an extremely brittle filament. It was so brittle I could flick it with my finger and snap it sometimes, and it consistently snaps during filament loading. The issue seemed to be that the dual idlers on the tension lever force the filament to the profile of the extruder gear. This replaces both idlers with a one idler option, which reduces grip but allows printing with this filament. 

It also gives the option to still use the same dual idler setup which offers slightly more grip for everything else. It allos you to quickly swap, and I havent noticed any difference in print quality. Be sure to use a strong material and 3 walls because the protrusion is a little thin.

For single idler: 1 Bearing 10mm od 5mm id 4mm width, m3x6 screw, and m3x6 low profile screw. I used prusament pccf. I realize people might not have the exact same parts (same reason I didn't use orignal bearings, too expensive) so I have included the step files too.

For dual idler: nothing, use original parts

If you dont print in 0.2mm layer height, the bearings may have slop. In the first photo you can see some slop because I forgot and used 0.25

When using the single idler I assit loading with tweezers, since I couldn't find a bearing with a groove

You will need to dissasemble the nextruder gearbox, and rerun the calibration (#9)