Introduction: DIY Self-Locking Nut

By Murray Woodcraft

The humble nut and bolt, they hold the engineering world together but sometimes they won't play ball and the nut wants to spin and fall off.

There are many ways to make sure the nut stays fastened:

  • Nylock nuts
  • Anti-vibe washers
  • Spring washers
  • Thread lock (glue)
  • Double nutting (see picture)

But sometimes you may not have the normal equipment or not have space for a lock nut, this instructable will show a handy hack that will keep a nut in place while leaving the possibility to remove it with a spanner.

Step 1: The Technique

All you need is:

  • Nut and bolt
  • Electrical heat shrink
  • Heat source
  • Spanners

It should be noted that this only really works for bolts larger than M8, any smaller than that and the thread is too fine and the nut won't fit.

The idea is simple, slide heat shrink over the threaded section of the bolt

Heat it until it shrinks into the threads, also shrink the bit sticking off the end (this will act as a guide for the nut)

Push the nut down the tail of the heat shrink and start to thread it on

It will be hard to turn, much like a nylock

The nut will strip the tail and it will fall off

As you thread down, the heat shrink fills up the thread and acts as a thread lock (THIS NUT WILL NOT VIBRATE OPEN!)

If you ever need to remove it, a spanner, some brute force and ignorance will open the nut, which will clean the thread of obstruction as it goes.

Simple, quick and handy