Below is a list of Aluminum Angle manufacturers from Belvidere, Illinois. Aluminum angles are aluminum parts that have been bent or conjoined to form an angle; they are among the most widely used metal parts in existence. The measure of an aluminum angle can be anywhere between 0 and 180 degrees in theory, though in practice the majority of aluminum angles measure near 90 degrees. Aluminum angles can be used as brackets in construction, to support shelving and have even been used to support flags when their edges are rounded.