100 mm Extruder calibrator

Gotta calibrate your extruder to get prints the right size. Place this gizmo on the filament 10mm above extruder and mark at both ends. Heat up your printer to operating temp. Manually extrude til the bottom mark meets the extruder, then immediately have your printer control software extrude 100mm in 20mm segments, pausing momentarily between segments.

The rest of the process from https://www.matterhackers.com/articles/how-to-calibrate-your-extruder

This thing was made with Tinkercad. E