Flat fender washers, defined in the DIN 9021 standard published by the German Institute for Standardization (DIN), are round flat washers with a larger outer diameter (OD) of approximately 3x inner diameter. These larger outer washers are typically used to distribute the load over a larger bearing surface than a standard flat washer. The washer should be placed under a bolt head or under the nut. This even distribution over a larger area reduces the possibility of damaging the bearing surface. A washer may also be used if the outside diameter of a mating nut is smaller than the hole in which the screw is inserted.
The requirements for flat washers with a large outer diameter are included in the DIN 9021 standard under the following headings:
Similarly, the ISO 7093-1 standard, published by the International Standards Organization (ISO), describes the characteristics of large series, product class A flat washers in hardness classes of 200 HV and 300 HV and nominal sizes ranging from 3 mm to 36 mm (nominal thread diameters). The ISO 7093-2 standard describes the characteristics of large series, product class C flat washers in 100 HV hardness class, nominal sizes ranging from 3 mm to 36 mm (nominal thread diameters). These washers are designed to be used where soft material pieces are to be clamped or where large clearance holes are present in the workpiece.
Oversized OD metric flat washers are round discs with large outside diameter round holes that provide a smooth bearing surface when used under a hex head bolt or hex nut head.
Our organization, among the numerous tests, measurements, analyses, and evaluations it provides for businesses in various sectors, also offers testing services for flat fender washers (OD approximately 3x diameter) under the DIN 9021 standard and for flat washers (large series) under the ISO 7093 standard, thanks to its trained and expert staff and advanced technological equipment .
To get an appointment, to get more detailed information or to request an evaluation, you can ask us to fill in our form and reach you.
