100mm/120mm Extruder Test Measure Stick

thingiverse

Probably a long overdue creation, but I designed something I needed. Dimensions are 5mmx3mmx120mm with a notch at 100mm from one side and 20mm from the other, plus a groove on one side measuring 2mmx2mm to lay filament flat. This device is a measure stick to test 100mm extrusions for my Ender 3 Pro. To use this tool, simply pull the filament halfway back in the Bowden tube and align it with the lengthwise step. The "^" notch marks the 100mm point, while the total length is 120mm. Mark both measures, then run a 100mm extrusion afterwards. Turn the stick around and check if the mark lines up with the notch – if so, your extrusion was accurate, and you're done! If not, measure the difference and adjust your steps/mm using the equation below. As an added bonus, measure the stick's total length to gauge your printer's dimensional accuracy: it should be 120mm x 5mm x 3mm, with the notch exactly at 100mm. The calculation is simple: divide 100 by the total length of filament extruded (e.g., 100mm ÷ 96.5mm = 103.62...). If you're over-extruding, the result may be negative. Now multiply this figure by your current steps/mm setting – my Ender 3's stock setting was 93 steps/mm, so I'd calculate (93 steps/mm x 103.62 = 96.37 steps/mm). Round up to the nearest whole number, and set a new step value (in my case, I'd use 96.5 or 97). Run another test, repeating all steps until your setting is accurate within at least one millimeter. Be prepared for large adjustments – you might need to repeat this process two or three times before achieving the desired result.