120mm filament marker - extruder calibration tool - 1.75mm filament

thingiverse

<h2>UPDATE 2: </h2> Since refining this tool, I've become smarter, better and more awesome. And apparently less modest. Anyway... The old picture of the tool showed me measuring filament at my extruder drive - this is a mistake. The correct way to actually calibrate your extruder is to unscrew your Bowden fitting from the hotend side and calibrate into free air, otherwise your motor won't be calibrated right. After that, you need to use a digital caliper to calculate your flow rate. The flow rate is the best way to offset different extrusion for different filaments, but the motor should be calibrated without any resistance from the nozzle to give all your materials the same correctly calibrated starting point. This tool is still super useful for this, but certainly the now deleted picture was no good. Sorry to anyone who inherited my wrong way to calibrate their extruder motor. UPDATE: I added a version with ruler marks as well. It's essential to print this in high resolution - 0.1mm or lower is a great idea. You'll also want to print it with 100% infill (almost no difference in used material but less risk of failure) and it's useful to run a marker across the surface to make the indents stand out more. Thanks to Reddit user /u/AhCup for the idea! I had a faulty extruder arm and I needed to do many calibrations, got so sick of the measuring tape sliding off and being less than precise. So I made this measuring stick with a slot that fits a 1.75mm filament. The actual slot is 1.80 to allow for even low-quality filament with large variations, but it still fits snugly enough on 1.75 that it's extremely useful. Just press the end against the Bowden tube fitting where the filament comes out, guide the extruded filament into the slot and use the measuring marks on the stick to measure how much your motor actually moved. For those who prefer to make marks at the extruder frame side, the little "window" at the end will let you make a mark at 120mm in seconds as long as you angle your marker against the edge of the little "window".