Weldables pre-cut kits utilize the slot and tab fit-up at intersecting joints for ease of assembly and welding. Slot and tab fit-up can reduce or eliminate the need for fixtures or jigs. usually all that is needed is a clamp, or often just snapping the intersections together will suffice until it is welded. Below is an example of the intersection of two 1.25″ tubes with the addition of a gusset to add strength. The steel tube is 12 gauge and the gusset is 1/8″ or .125″ plate.