This works great. So glad I found this. I'll post a make once it is done serving filament to my current print job.
One thought / recommendation: I'm feeding an Original Prusa i3, and don't have any kind of feed tube that connects to the arm. I just run the filament through the open 3mm hole (i'm using 1.75, but thought the extra clearance would be better since I don't have a tube). Would it be possible to make another arm that has a much simpler guide hole? I'm thinking drop the cleaner/oiler port and just basically have a nice smooth reverse funnel with a narrow opening sized for 3mm or slightly bigger. The filament can then enter at the "bottom" of the funnel and exit the "top" of the funnel with a nice smooth surface that lets the feeder be above or below the top of the printer.