Locking washer Nord Lock DIN 25201

Nord-Lock locking wedge washer DIN 25201 is a steel pair, consisting of two toothed washers with wedges on one side and radially arranged teeth on the other side. The washers are installed with the wedges facing each other during assembly. Washers are used in critical joints subject to vibration and dynamic loads. The shape of the washers is such that they block the possibility of loosening the connection. Nord-Lock washers fix the connection by tension, not friction. The wedge angle of the washers α is greater than the thread pitch of the bolt β. A “wedge effect” is created, which prevents the bolted fastener from turning itself.

To ensure reliable fixation of the fastener, the hardness of the mating surfaces must be lower than the hardness of the Nord-Lock washers. For large or longitudinal holes, on fragile materials and on painted surfaces, use Nord-Lock “sp” washers with an enlarged outer diameter. For even load distribution, use Nord-Lock “sp” washers with flange bolts or nuts.

It is recommended to use a lubricant when assembling the connection, which reduces friction and stress, prevents abrasion and scoring of surfaces, and allows for reuse.

The reliability of Nord-Lock locking wedges has been confirmed by numerous vibration tests according to DIN 65151 and NASM 1312-7 standards. Nord-Lock washers are certified by the TÜV Institute for quality and safety.

It is not recommended to use Nord-Lock washers:

For mating materials with a hardness higher than that of washers
For very soft materials (wood, plastic)
For joints with high shrinkage
For connections without pretensioning

Tolerances for Nord-Lock lock washers:
NL3 – NL8 O ±0.1 mm; NL10 – NL42 O ±0.2 mm; NL45 – NL130 O +0.5 / -0.0 mm.
NL3 – NL24 O ± 0.2 mm; NL27 – NL42 O ± 0.3 mm; NL45 – NL130 O +0.0 / -2.0 mm.
NL3 – NL42 T ± 0.25 mm; NL45 – NL130 T ± 0.75 mm.
Nord-Lock washers with a thickness of 6.6 mm have a thickness tolerance of +0.0/-0.5 mm.