Computer stand based on a ST12x40 AISC Steel Section. Has 3/4" Bolts (no threads) and bevel washers for printing as well. Those are dimensionally accurate, so they should fit actual bolts if you want to get fancy. Additional stiffness is provided with pen organizers on both sides (in lieu of gusset plates).

Computer stand is flared to fit 26mm at the base and 28 mm at the top.