Need a Vice?

 Clamp-on vices are never satisfactory. They slip and twist and the surface is scared. They are not strong enough. My solution is a drill press vice mounted to a sheet of plywood. The underside of the sheet has cleats which prevent the vice from twisting or sliding. It also provides a work surface you are unafraid of scaring.

 I had the vice (it normally lives on my drill press at home--oddly enough, to hold metal bits that that are being drilled), but it would only be ~ $40 at Home Depot or on Amazon. Multiple holes allow mounting at 90 degree orientations.

The bolts grab T-nuts, saving time. The sheet can be slipped into the locker for storage.

 Sometimes you can jam a part between dock boards or hold it with Vice-Grips, but sometimes you need both hands plus the firm grip that only a solidly mounted vice can provide.