Extruder Indicator

My Rostock Max has a top-mounted extruder for its bowden tube feed, and the motor shaft end is towards the front. Pretty cool, because you can see the filament feeding through the hobbed gears and stuff! But... kind of hard to tell how fast or slow it's actually moving filament.

This... is a pointer. It goes around. How fast is your filament going? Well, see how fast the pointer is going around.

Technology.

Notes: This was designed for a NEMA 17 with a 5mm diameter drive shaft. It's a pretty tight fit (I eyeballed this in 5 minutes in zbrush, which is not exactly a precision CAD program). Print it at maybe 102-105% if you don't want to file the inside to fit.