How to Measure a Lock Nut

You do not need a Vernier or Digital Calliper to identify a Lock Nut; a standard ruler is usually sufficient. 

Measure the Bore Diameter

Measure the inside Diameter (Bore) of the Lock Nut in millimetres. 

Divide the measurement by 5

To determine the Lock Nut size, divide the Bore Diameter by 5.

Example

• 50mm ÷ 5 = 10 - MB10, KM10, KMFE10

• 30mm ÷ 5 = 6 - MB6, KM6, KMFE6

Quick Formula

Lock Nut size = Bore Diameter (mm) ÷ 5

This method provides the nominal Lock Nut size and is suitable for identifying most standard Metric Bearing Lock Nuts.

You can browse our range of lock nuts here.