This design is a cleaving plier used to precisely apply uniaxial stress on a silicon or a glass sample and break it cleanly. For those unfamiliar, you first make a notch with a diamond tip where you want to cut the sample, and then you use the pliers to apply pressure. The sample will brake along the crystalline direction for silicon, or in the direction of the pressure for glass.

You can find this type of pliers is specialized shops but i could not find a pair small enough for my use. So here are 4 different models ranging from 7 to 18mm wide.

You just need to print the 3 STL that compose the size of your choice and assemble the two handle parts with the central screw. The hexagonal hole on the screw is designed for standard 6.5mm screwdriver bits.