DIN 125 is the industry-standard specification for Plain Washers, designed to be used with hexagon bolts and nuts. Its primary function is to provide a smooth bearing surface and distribute the clamping load over a larger area, preventing surface deformation of the clamped components during assembly.

Divided into Form A (without chamfer) and Form B (with chamfer), DIN 125 washers are indispensable in mechanical engineering, construction, and automotive industries, ensuring the structural integrity of bolted joints under operational stress.

The technical utility of DIN 125 lies in its load distribution capabilities. By increasing the area over which the nut or bolt head bears, it reduces the compressive stress on the fastened material. Form A is the standard flat execution, while Form B features a peripheral chamfer for aesthetic and technical clearance in precision assemblies. The hardness of the washer must be compatible with the property class of the bolt to prevent "cupping" or deformation.