MK3 Filament (Spool) Extrusion Indicator

I wanted a rotation indicator for the E-axis on my MK3s but wasn't drawn to any I found.

This prints in three pieces that snap together. The spindle is keyed to prevent the halves of the "spool" from getting misaligned. Features a strand of filament that you can use as an indicator if you are trying to gauge full rotations of the motor. Mine works with three 8mm x 3mm magnets. Two almost worked but would slip frequently.

Also makes a great fridge magnet.

Print instructions

The design expects 0.15mm layers and may struggle with nozzle sizes larger than 0.4mm. 10% infill should be plenty.

• Take care when removing the filament print from the bed. The little strand of filament breaks off easily.
• Cut the little built in support off the end of the filament strand.
• I do this with side cutters before removing the print from the build plate.
• Press one magnet into the spindle on the back piece.
• The back is the one that doesn't have a hole all the way through.
• The inside of the spindle is recessed by 1mm. Make sure it's all the way in. there should be about 1mm of space left at the top of the spindle. pictured
• Snap the front and back on to the filament taking care to alight the key ridges on the inside of the filament with the slots in the front and back spindles.
• The front will snap in place more easily than the back due to the magnet preventing the back's spindle from flexing.
• Stack two more magnets on the outside of the back then attach to your stepper motor.