This is my welding bench vise. it's actually on an old Craftsman roller toolbox, and the box has a 1/2" steel plate on top as the welding table, but I actually use the vise more than the table. Magnet ground to the table top, that top has a ground wire over to one of the vise mounting bolts, and there is a secondary grounding wire off the same mounting bolt with a clamp for loose parts to be welded.
The vise is an old Lakeside and while only 3" wide jaws, opens over 4-1/2". Light homeowners vises like this typically weigh from 10-15 lbs, and are more than adequate for light welding. It's both ground clamp and welding vise, and works well.
Here is it with a UMD (Universal Measuring Device) for scale: