There are several different methods to address – and try to prevent – the issue of vibrational self-loosening of bolts.

Most of them include the use of additional mechanical devices, to lock the threaded assembly and maintain the desired clamp load.

Double nut increases contact through more thread interface.

Spring washer increases bolt tension through spring action.

Nylon insert creates interference between bolt threads and the nylon insert.

Toothed flanged bolt digs into the surface to provide interference fit.

However, none of these methods tackle the gap existing between the threads of the bolt and the threads of the nut. The gap appears tiny to the naked eye, but it’s still large enough to allow side to side movement of the bolt within the nut caused by operational vibrations. This movement will eventually cause the bolt to loosen, regardless of the mechanical device used to lock it.

The only way to address the issue of gap is to use a liquid Threadlocker which completely fills the gap between the threads, solidifies into a tough thermoset plastic between the two metal surfaces in the absence of air, and in that way prevents any side to side movement. While bolts secured with mechanical fasteners will gradually lose the clamp load after only a few cycles and much before they loosen completely, the bolts secured by Loctite Threadlockers maintain the clamp load throughout (Junkers vibration test).

Apart from being the only efficient way to lock your threaded assemblies (as permanently as you choose to), Loctite Threadlockers also prevent corrosion and galling, increase reliability of your machines, prevent unplanned downtime, increase service life of your end product (in case you’re building them into machinery or devices you’re manufacturing) and minimise costs and complexity of your inventory. For illustration, below picture shows the quantity of spring washers needed to secure 850 pcs of M10 bolts, as opposed to a 50 ml bottle of Loctite 243, which does exactly the same thing, only more efficiently.

Would you like to sample Loctite 243? You can request a sample from your local Loctite team (select your country at the top navigation on the website).

Or if you’re not ready to sample yet, keep an eye on our webinars calendar and join us in one that suits your needs most to find out more about liquid threadlockers first.