How to specify a self locking nut and what questions need answering?

What questions do we have when you want to use a new locking nut?

One would think that self locking nuts can be used with any bolt in every application.

dependant on the application, the material of the bolt, the properties of the components that are screwed together and other technical requirements... one self locking nut will be better then another one.

In order for us to recommend the best self locking joining nut, please give us following informations:

- What are the properties of the material that is between the head of the bolt and the nut.

- what are the properties of the bolt? diameter, pitch, length, material, plating

- Application Technical details

- What was the previous solution used?  What do you want to get improved? (Friction coefficient and required tightening torque)


Having said that,

the most popular items are class 8 steel and stainless steel A2

The finition of the nuts are standard as follows:

- class 8 with lanthane finish and a topcoat which protects the nuts to a 600 hours salt spray test

the top coat is a requirement in the railway industry, where a lot of vibration exists.  The topcoat provides a tighter tolerance on the friction coefficient

     (0.15 +-0.03) = with top coat
     (0.15 +-0.08) = without top coat (means a more difficult installation)

- stainless steel A2 with Stanal top coat to resist against galling (the nut and bolt are getting otherways fixed with each other)  ; thanks to this material the temperature range is from -200°C to +400°C

You can discover the self locking nuts here:

preferred model = JLd = double slotted nut

The use of the the correct nut in your application, will give it a longer lifespan and less maintenance required.