Hex Head SEMS Screw Black Plating Pozidriv Double Washer Screws

Hex head sems screw is the screw with a double washer attached and hex pozidriv head. 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.

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).

The Pozidriv is an improved version of the Phillips screw drive. Pozidriv was jointly patented by the Phillips Screw Company and American Screw Company. The name is thought to be a portmanteau of the words “positive” and “drive.” Its advantage over Phillips drives is its decreased likelihood to cam out, which allows greater torque to be applied. In ANSI standards, it is referred to as “Type IA.” It is very similar to, and essentially compatible with, the Supadriv screw drive.
Pozidriv drive bits are often designated by the letters “PZ” plus a size code of 0, 1, 2, 3, 4 or 5 (by order of increasing size); the numerical bit size codes do not necessarily correspond to nominal screw size numbers.

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