Adrian Brentnall wrote:
I use diamond hole drills for glass-work.
They consist of a hollow tube, with diamonds bonded to the
'business end' of the tube.

Might it be possible to use one of these as a sort of 'auto-file' -
just to grind off the corners from your square pins ?

When used on glass, they need water-cooling -
don't know if they'd need that for metal-cutting.

Alternatively, can you find somebody who can drill a 1mm hole into the
end of a dremel-style mounted abrasive drum - that you can use to
re-form the end of the mains socket pins.

Hmmm... there's an idea. I could laser cut a small piece of glass to the
appropriate size with a hole in it, and then epoxy that in the end of a pen
or similar (tolerances between pins are quite tight, so the tool has to be
pointy). I'm only cutting copper, so it should be reasonably soft and
amenable to glass. However if this goes wrong it sounds like a recipe for
blood.

I'll see if there's any Dremel fittings lying around I can
abu^H^H^Hexperiment upon...

Don't know what the effect might be of removing material from the pins -
they might be plated to aid solderability, so you'd need to know that
whatever's under the plating will solder OK - also that you're not
affecting the current capacity of the socket (are there approvals
issues, perhaps ?)

No approvals issues, and taking off 0.4mm off the corners of the pins won't
do too much harm to the current capacity (the straight-through connectors
have smaller pins and the same current rating).

Now rummaging in the kitchen to find glass jars small enough to laser
cut...

Theo