While sawing dovetails for a jewelry box, I found my back was hurting from hunching over my bench vise. In order to work more comfortably, I built this vise extension that works on the same principle as a leg vise. The fixture is nothing more than a couple short sections of 2×12 lumber connected with a veneer-press screw [Amazon]. The longer rear board clamps into my bench vise, while the front board adjusts in and out by turning the veneer-press screw. In use, the workpiece gets clamped between the two boards, projecting from the top at a much more comfortable working height. The tops of the jaws are chamfered for easier workpiece access and tool maneuverability.
To keep the jaws parallel under clamping pressure, simply insert a shim at the bottom that’s the same thickness as your workpiece. To prevent a workpiece from slipping downward when tapping on it with a chisel or other tool, rest the lower end of the workpiece on a tall shim board. The fixture can be made in any size to suit particular types of work, and the clamp can be reused in different-sized vises if desired. — Hunter Cox