Question: When I am installing a stainless steel nut onto a stainless steel bolt, quite often the nut binds and I can’t tighten it or remove it. Why is that and what can I do to prevent it from happening?
Answer: That is what we refer to as GALLING. Galling occurs during installation when pressure and friction cause the threads to seize. Once a fastener has seized it is virtually impossible to remove without cutting the bolt or splitting the nut. Heat generated is the major contributing factor so extra care must be used when installing nylon locknuts. Stainless steel is the worst metal for galling.
To help reduce galling, slow down the installation and use either an anti-seize compound or lubricant.