WASHER TYPES Beveled Top-bearing surface is cut at an oblique angle to compensate for nonparallel surfaces in structural leveling and shimming applications. Can be round or square. Conical or Spring Slight dish shape and edges sheared parallel to the center line increase elasticity of joint for absorbing shock and maintaining tension under dynamic loads. Countersunk Allows flat or oval head countersunk screws to be flush with surface for finished appearance. Fender Large outside diameter provides extra-wide bearing surface for distributing force/stress; covers oversized holes. Flat The most common washer, with 2 flat surfaces for distributing force/stress of a nut or bolt and reducing friction and heat during installation of a threaded fastener. Can be round or square. Ogee Oversized, curved bearing surface keeps bolt heads and nuts from pulling into wood. The load-distributing ogee curve can serve as a force spreader in structural use. Raised Has a large bearing surface and raised reinforcements for structural use with high-strength fasteners.

Retaining Feature a specially configured inner diameter that slides on the screw easily, but then grips the outside of the screw shank for retention. Ideal for preassembly and kitting. Shoulder Barrel protrudes from center hole of flat-bottomed washer to isolate or insulate a screw, shaft, or rivet. Slotted A slot the same width as the hole diameter is cut from the center to the perimeter. Slips on and off shaft without removing fastener. Spherical 2-piece equalizing assembly with 1 flat washer and 1 dish-shaped washer. Eliminates unequal thread loads and stress from nonparallel surfaces. Split Lock Split with 1 end bent slightly outward to bite in and prevent loosening. Acts like a spring under compression to provide extra holding force and decrease frictional resistance during assembly and disassembly. Tooth Lock Also referred to as star washers. Directional teeth or serrated edges bite into fastener head/workpiece to prevent loosening. Wave Wavy shape provides compensating spring force, increases load-bearing capacity, absorbs shock and vibrations, and resists loosening and fatigue.