Chicago Screw - Aluminum - 1/2" (5)

This type of fastener has a barrel-shaped flange and protruding boss that is internally threaded. The boss sits within the components being fastened, the flange provides the bearing surface. The screw post binding often has a built-in feature, such as a slot, to aid in tightening the fastener. More commonly known as "architectural bolts" or '' Chicago screw'', these screws have knurled barrels to allow one-sided assembly. It is normally chosen because of its low profile compared with other nuts.