I saw a really cool soldering helping hand tool at my local amateur radio club meeting. So I did a search and found and printed https://www.thingiverse.com/thing:2757071 by Mistertech. I really like the original, but being a mechanical engineer I wanted to redesign it to work the way I need and to take better advantage of how a 3D printer makes parts.

The things I wanted different are the following;

1. I needed bigger things to grab to open the jaws with one hand while I feed a wire to solder.
2. I don't have the small diameter feet in stock that is used on the original, but I do have a bunch of real thin feet, so I didn't need pockets for the feet.
3. I wanted bigger teeth with the top one able to grip really small wires. I also wanted a shelf structure to hold flat things.
4. I wanted to print all the jaw parts with the cross-section of the jaws in the X-Y plane so that the teeth and the pivot can be made with a better fit.

This is my result. I included a step model in the file list, so if you want to do a remix, you won't have to go through the process of curve fitting the .stl files.

Print two copies each of the rotating and static jaws and one base. I printed mine on my Creality Ender 3 Pro using HTPLA+ (3D870 from Nature Works) filament from Fusion Filaments