Spring Loaded Caliper
by ianjohnson, published
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.
I added a version that has a built in filament guide and a wider mounting plate.
In addition to the printed parts you will need:
4" Pittsburgh caliper from Harbor Freight
2 608 bearings
2 M8 x 20 bolts
2 M8 Nuts
4 small sharp screws
1 small spring, about 1.5" long.
The part with the mounting arm goes on the fixed jaw of the caliper, and the smaller part goes on the sliding part. There are small starter holes for the screws which hold the spring.
You can try to drill through the steel caliper jaws, but I found that loading it up with superglue works fine. Just make sure that the bearings stay flat and aligned with each other. If one ends up cocked at a little bit of an angle, it will push the filament out to one side and the measurement will change as the filament moves from one side of the bearing to another.