I needed a vise that can hang on to small 3d printed parts to do finishing work without damaging them. This is what I came up with. 

In my video I cut a slot in the bolt to insert a retaining clip. If you don't want to do this, you can install a spring on the bolt in between the two jaws.

I printed this with 100% infill

Parts List: 

M5 50mm bolt

M5 nut

Retaining Clip or Spring