OK, OK, I understand some folks want things that can be completely made on a 3D printer, but there are limitations, especially when it comes to structural strength in the layer directions.
That being said, I like the design of the small vise, I just wanted more reliable hardware - As in metal screws. While this does require a bolt and a nut (or Two), I find it to be very smooth and precise.
You will need:
1 ea.1/4"-20 X 4.5" (Or 6mm X120mm) full thread bolt. It's hard to find full thread hex bolts, but if you look for "Carriage bolts," they have full threads. They also have a round head with a square part underneath, because they are designed to bolt wood parts together. The "Carriage Knob" file is the proper knob for this kind of bolt.
1 ordinary hex nut to fit the above bolt.
1 "Nylock" type lock nut and flat washer (Optional; this is used on the end of the bolt to keep it in position. I used a nylon washer, but a metal washer will work as well).
Print in the orientation given. Supports are only needed on the jaw, for the nut cavity.
Clean out the holes if necessary for a smooth fit. Put the bolt through the knob. Tighten the nut to pull the bolt into the knob. Put the regular nut into the jaw, tighten the knob to pull the nut into the jaw. Put the bolt into the body from the fixed jaw side, drop the jaw into the body, and thread the bolt through the jaw. Install the washer and Nyloc nut on the end of the bolt where it protrudes from the body. The bolt should turn freely.