My filament kept catching on the starting connector of my Bowden tube. So I got a pack of dollar-store cheap pencil sharpeners to try.

Nope. Way too big. So I modeled my own in SketchUp and printed my own to fit the blade they use. Works--after a third revision.

• Slice the STL at .2mm layer height to your printer's needs.
• Print it.
• Get a pack of cheap pencil sharpeners from a dollar store or their ilk.
• Using a small phillips scewdriver, remove the screw holding the blade and CAREFULLY take out the blade.
• Put the blade in your printed sharpener with the business end over the angled hole.
• Attach blade with screw form old sharpener.

To use:

• Place sharpener over 1.75 mm filament end.
• Hold filament firmly and rotate sharpener.
• Don't push too hard. Let the tool do the work.
• Removed pointing filament.