Stock Drive Products & Sterling Instrument - SDP/SI External Lock Washer, #4 Screw Size, 0.25in. Outside Diameter, .016in. Thick, Material- Stainless Steel. A 9X21-E04

Industrial fasteners are hardware devices that join two or more items together, creating a semi-permanent or permanent connection. The fasteners most frequently used by machinery designers are screws, nuts, retaining rings, and various types of pins because of the basic role that they play in the assembly of mechanisms. Various industrial hardware components are used in the assembly process including knobs, washers, spacers, shims, handles, springs, spring-powered reels, and ball plunger screws. Fasteners play a vital role in a wide range of applications, from everyday household items to medical devices, robotics, and even outer space. Careful consideration must be given before selecting the most appropriate fastener for an application. Download Reference Tables to help with selection: Standards for inch-size Size Fasteners Screw Head Dimensions Metric Thread Specifications