1. DIN 9021 is a standard created by the Deutsches Institut für Normung (DIN) in Germany. It specifies the dimensions and requirements for plain washers with a larger outer diameter than those of regular washers. These washers are commonly used in various industries to distribute the load of a threaded fastener, such as a bolt or screw, over a larger surface area. The standard ensures that these washers meet certain criteria for their size, material, and performance, providing consistency and reliability in their functionality. Adhering to the DIN 9021 standard helps to ensure the safe and efficient use of these washers in different applications.