Self tapping screws into well worn holes?

[Woodlouse]

You could set the screws in with epoxy. A light coat of Vaseline would ensure you can extract the screw afterwards. Also backing the screw off a crack to break any bond just before the epoxy sets completely works as well.

 

[Poignard]

You can also use frying oil spray (eg Frylight?) as a release agent. Recommended by WEST.

 

[Ruffles]

The best idea seem to be a treaded insert, and replacing the self-tappers with set screws. That would give a good long term solution to floor boards which have to come up periodically to access stuff for maintenance.

Not sure I'd do that on the floor. Likely to corrode even if the insert is brass.

I'd use a No8 plug drill and taper plug cutter set to insert a hardwood plug. That way the grain is running the right way. And when it fails again you can just re-do it.

 

[Ian_Edwards]

Just a quick note to thank everyone for their contributions, and provide some feedback on the solution I eventually used.
I used 5mm SS rivet nuts, these are normally used for fixings to thin sheet material.
I simply drilled holes which were an interference fit for the rivet nuts, where the mangled screw hole was, countersunk the holes and then glued the rivet nut in with 5min Araldite.View attachment 55808View attachment 55807View attachment 55809

I used cheese head bolts with Allen Key socket to fix some upholstered panels, the Allen Key made it much easier to get the 5mm bolts to locate, where the access was very difficult, because the Allen Key and socket head hold the bolt so it can be poked down holes.

For floorboards I uses CS SS setscrews, again with an Allen Key drive.

The rivet nut provide a very firm and reusable method of fixing things, but I'm not sure I'd use then in high load applications.