Painted Surface

When tightening towards a painted surface sliding may occur towards the paint if there is a thick and soft layer of paint. If the paint is hard, the sliding will occur between the upper washer and bolt head/nut. In both cases there will be a positive locking effect since the sliding in off-torque direction will be on the cam faces of the washers where the friction is lower than on the serrated surfaces.

Painted surface after
use of NORD-LOCK
(standard diameter).

Painted surface after use
of NORD-LOCK sp
(large outer diameter).