very accurate volumetric flow meter

A flow rate meter that shows volumetric speed of your printer with decent accuracy by clamping the filament.

Each notch on the disk represents 10 cubic millimeter of filament for 1.75d, a full revolution means 100 cubic millimeters of filament gone.

Assemble with three M3X18 threaded bolts, three M3 locknut (optional)

Glue eight 6mmx3mm magnets with epoxy. 

Print with inner hole expand by 0.1~0.2mm; file down any burrs and extra bits.

also play with the geometry to get the best results.

Tip: the measurements from this gadget is for reference only, data could vary due to slips and random errors and are often under-measured.