NS EN ISO 7091 : 2ED 2000

Defines the characteristics of normal-series, product-grade-C plain washers in the 100 HV hardness class and of nominal sizes (nominal thread diameters) ranging from 1,6 mm to 64 mm inclusive. Washers of hardness class 100 HV are suitable for: hexagon nuts of product grade C in property classes up to and including 6; hexagonal bolts and screws of product grade C in property classes up to and including 6,8; case-hardened thread rolling screws. If dimensions other than those listed in this Standard are required, they should be selected from those given in ISO 887. When large clearance holes in the workpiece are used or soft material pieces are clamped, the user should check the technical suitability of this type of washer.