Abstract: A metal threaded fastener is disclosed for use in outdoor or other environments where fastener rust or corrosion are to be discouraged. The fastener includes a metal head adapted for engagement with a torque wrench or the like. The head is covered by a polypropylene jacket. Raised metal protuberances below from a bottom clamping surface of the head. In one embodiment, these protuberances extend at least partly through the polypropylene jacket, but the thin covering layer of polypropylene is displaced from the protuberances during bolt installation. These protuberances provide metal-to-metal contact with a workpiece, and consequently encourage maintenance of a correct axial clamping pressure without over-torquing the mating nut.

Abstract: A bin ladder construction includes a vertical ladder up the side of a grain storage bin and an inclined ladder from the upper end of the vertical ladder to the peak of the roof of the grain storage bin. Corner pieces of particular shape and configuration interconnect the inclined and vertical ladders. The ladders have hollow rungs open at both ends, and channel members extend through and beyond the ends of a pair of hollow rungs in the vertical ladder and in the inclined ladder. Triangular brackets mount the opposite ends of hand rails to the ends of said channels.