I used solid 2x6 on the sides and cut 2x6 pieces between the 2x6 cantilevered beams. It is bolted it all together with 4 carriage bolts per joint to form a mortise and tenon joint. The horizontal beams have 1/2 shoulders to resist the torque. It was cut very precisely and the beams were very level unloaded. I should check again now that it has the lumber loaded. I used the same design in my previous shop. It held the same wood for a very long time.