On Sun, 02 Nov 2008 13:24:46 +0000, Rod
wrote:

wrote:
On Sun, 02 Nov 2008 11:23:19 +0000, Rod
wrote:

Having looked further, I have found another oddity - the screws. Most
screws for back boxes I have seen have either been ordinary machine
screws with a straight-across cut end, or slightly fancier ones with a
step and an unthreaded bit which seems to help with locating them.

The Clipsal Converta 2 to 3 socket came with screws the like of which I
don't think I have ever seen! So here is a pictu

http://www.flickr.com/photos/polyurethane/299513

I have a feeling that they might actually work well - but will not know
until I have tried. But does anyone know what this sort of screw end is
called?

Lok more like self tappers .

Yes - but the tapered thread seems no sharper edged than a normal
machine screw thread. And is only very short so is quite rounded/blunt.

Having now used them, they did seem to locate well - something that is
quite often awkward with the normal forms. I think that if they approach
the threaded hole slightly off-centre, that end bit will tend to centre
the screw.

Was it a plastic surface box you fixed them to or a metal one ?