Spring Loaded Caliper

A mount to add bearings and a spring to a caliper so you can measure filament as it runs between the bearings. There is a mounting arm so you can add it to a filament winder, or set it up between two spools to check the size or deviation of some filament. It works best if you have some good guidance for the filament before and after the caliper, because the filament will tend to slip off the bearings to one side or the other.

Update:

I added a version that has a built in filament guide and a wider mounting plate.