10-32 x 1.75 in. Hex-Slotted Drive Screw. Machine thread type is used in a pre-tapped hole with or without a nut. The Hex Washer Head has a flat washer that extends beyond the sides, providing it with a greater bearing surface than a normal hex head fastener. The washer and the Hex Head are bonded together as one piece; this offers greater protection to the mating surface than a standard hex head. The increased bearing area decreases the likeliness of crushing mating surfaces. Zinc plating, retards the corrosion rate in a normal atmosphere.