The present invention provides an adjustable bar clamp leveling device operable to receive a plurality of conventional woodworking bar clamps and provide space above and below a workpiece for positioning cauls and clamps to the workpiece a glue-up. A plurality of bar clamp leveling devices may be incorporated into a workbench with or without T-slots for securing a workpiece at various positions while maintaining planar alignment of the workpiece components during a glue-up.