The NORD-LOCK nut is a self-locking nut that prevents bolts from loosening. It consists of two serrated washers that interlock when the nut is tightened, preventing the nut from loosening. The NORD-LOCK nut can be used in a variety of applications, including automotive, construction and industrial.
NORD-LOCK locking washers are supplied as a pair of washers whose inner faces include ramps with an angle greater than the thread helix angle. Each washer also has radial serrations on the opposite face, and the washers are installed in pairs, cam against cam.
When the screw and/or nut is tightened, the serrations anchor the washers to the contact surfaces and movement is limited to the cams. The guide covers mounting on a bolt, with oblong holes or creep-sensitive material, and on studs, and states that flat washers must never be placed under NORD-LOCK washers. This manual is written in French.
No, flat washers must never be interposed under NORD-LOCK washers.
They are positioned in pairs, cam against cam.
The NORD-LOCK washers secure the nut, avoiding the use of glue.