Taper Washer:

Taper Washer are square or half round, Taper washers are designed to be used on channel sections, underneath nuts with tapered flanges to enable the bolt assembly to fit square when tightened. Beveled washers are square and while one bearing surface is flat, the other has an oblique angle. Used in structural applications, they are designed for leveling and shimming purposes and are commonly used when bolting through the flanges of I-beams.

General:

A beveled washer is used with a threaded fastener, such as a bolt, to shim or level an object. A beveled washer can meet standards, such as American National Standards Institute (ANSI) B18. 22.1, and can have inch or metric measurement. Beveled washers are square and while one bearing surface is flat, the other has an sloping angle. Used in structural applications. They are designed for leveling and shimming purposes and are commonly used when bolting through the flanges of I-beams. Bevel washers are used mainly for faucet seats that are damaged or wore beyond stem travel, therefore the thicker washer makes up the difference. The bevel washers attempts to seal the water flow from the interior opening of the seat, rather than the flat raised edges of the seat. The beveled side should touch the water jug on both inside and out. The bolt on each side fits into the washer and forces it into the rim of the opening. The bevel side goes inside towards the bolt.