The pics of the drilled bolt head on the parent page were not clear to some observers


The nuts have holes drilled in them through which the safety wire is threaded, then twisted until the untwisted wire is just the right length to be fed through the holes in an adjacent nut.
The wire is threaded in such a way that any nut starting to work loose due to the vibration will pull tighter the nut to which it is attached.

next