Simplify3d has a good guide for this. They have a whole section on the hobbed bolt chewing into your filament. One thing they don't mention is: how difficult is it to feed filament into the extruder? I had this issue before building a better spool holder that eases the spools' ability to rotate and thus feed filament. I noticed as the X axis would move (especially during retraction), it wasn't able to pull enough filament down and the filament would essentially get "stuck" and the hobbed bolt would chew a crescent shape and stop extrusion. Some people have gone as far as to add bearings to their spool holders, but I haven't found this necessary as of yet. The wooden spool holder was creating too much friction on certain spools, and adding a carriage bolt through a double ended brass hose fitting (I happened to have laying around) in place of the stock wood holder fixed this issue for me.


https://www.simplify3d.com/support/p...iddle-of-print