Andy redesigned the 4-way parallel clamp and now it is even better! The original design had an adjustment screw for different thickness of wood and it also had kind of a hook on the end where the two clamps nested together.
The new design has eliminated the adjustment screw and the hook has been replaced with something that looks more like a regular parallel clamp.
I have the actual prototypes in my shop in Minneapolis and Andy is in Denver. We posted corresponding videos to describe the revised design.
-- Adjustable Height Workbench Plans http://www.Jack-Bench.com