I built mine out of 2x2, 1/4 wall square tubing. it works okay. I built it to be able to handle a 24 inch wide piece but it flexes too much in the middle that wide, even with 22 gauge. I can do up to 16 gauge, 12 inches wide, or about 16 inches wide with 22 gauge. I think I need better downforce in the center of my clamp piece, which is 1/2 inch flat bar stock.