I'd run it between two rubber wheels, one to measure, the other to hold it tight to the measuring wheel to prevent slipping. As long as the thread isn't super thin and it's a flat, even, sticky enough rubber wheel, it should work. Then you just have to count/convert rotations of the measuring wheel to the length.
abfarrer t1_itrrym3 wrote
Reply to How can I measure the length of string passing through something? by Dabrush
I'd run it between two rubber wheels, one to measure, the other to hold it tight to the measuring wheel to prevent slipping. As long as the thread isn't super thin and it's a flat, even, sticky enough rubber wheel, it should work. Then you just have to count/convert rotations of the measuring wheel to the length.