Our first project... Theresa helped me construct two 4'x8' workbenches that could be placed end to end (4'x16') for wing or fuselage construction. The corners are 4x4s while the rest of the framework is constructed with 2x4s, metal gussets and wood screws. The lower shelf is 3/4" standard ply, the top layer is 5/8" (10-ply) cabinet grade birch. Once they were transported to the hanger, we installed the leveling feet that Scott Lacy fabricated (perfect fit and they work great) and also installed 1x4 cross braces. These things are solid.