SEMS Hardware Screw Washer Assembly Screw With Washer Attached

SEMS hardware is also known as washer assembly hardware. SEMS screw combines two separate parts into one pre-assembled, low-cost fastener. With washers under the head, SEMS screw is fast, permanent, and easily adaptable to many applications. Ever Hardware provides custom-made fasteners and customizable packaging.

The Phillips screw drive was created by John P. Thompson, who after failing to interest manufacturers, sold his design to businessman Henry F. Phillips. Phillips is credited with forming a company (Phillips Screw Company), improving the design, and promoting the adoption of his product. The original patent expired in 1966, but the Phillips Screw Company continued to develop improved designs.
Phillips drive bits are often designated by the letters “PH”, plus a size code 0000, 000, 00, 0, 1, 2, 3, or 4 (by order of increasing size); the numerical bit size codes do not necessarily correspond to nominal screw size numbers.

A washer is a thin plate (typically disk-shaped) with a hole (typically in the middle) that is normally used to distribute the load of a threaded fastener, such as a screw or nut. Other uses are as a spacer, spring (Belleville washer, wave washer), wear pad, preload indicating device, locking device, and to reduce vibration (rubber washer). Washers usually have an outer diameter (OD) about twice larger than their inner diameter (ID).
Washers are usually metal or plastic. High-quality bolted joints require hardened steel washers to prevent the loss of pre-load due to Brinelling after the torque is applied.
Rubber or fiber gaskets used in taps (or faucets, or valves) to stop the flow of water are sometimes referred to colloquially as washers; but, while they may look similar, washers and gaskets are usually designed for different functions and made differently.