Lock Nuts - Metric

Sometimes written as lock nuts, they also go by various other names, including half nuts, jam nuts and thin nuts.

Locknuts are used to lock a full nut in position to prevent it from working loose as a result of vibration or other factors.

Locknuts are often mixed up with Nyloc nuts, which are different. Nyloc nuts are self-locking nuts that feature a nylon collar in the top portion of the nut that locks the nut in place.

About Metric Thread

The most common thread type in production today. Usually specified as M then a number x another number. This signifies the thread diameter and the length of the fastener.

For example, M4 x 30 means that the major thread diameter (the external distance across the outside of the thread) is 4mm and the length is 30mm. Length is usually measured from the underside of the fastener head.