"2987fr" wrote in message ...
Murmansk wrote

I'm trying to dismantle one of those outdoor swings - like a wooden sofa suspended on
chains from a wooden framework with A shaped supports at either end.

The bits of timber are attached with what I think are called coach bolts - a domed
head with a square bit underneath.

Yes, that's a coach bolt. Originally used on real coaches,

The problem is that the bolts are recessed down a hole. I can turn the nut with a
socket set but because it's a all a bit rusty and seized up the head of the bolt turns
as well and I can't get hold of it to stop it because the head is domed and down a
hole.

Any ideas how I can get hold of the head to stop it turning?

You can drill a hole into the dome, into the square knob thing under
the dome and put a thing a bit like a thread tap, but tapered, forget
the name, into that hole and put a spanner on the square end of
the thing I cant think of the name of.

Once youve drilled a sufficiently large hole in the head it will separate
from the shank and you should be able to punch the bolt through
to the other side, ideally (or ironically) using a similarly sized bolt
using the mushroom head to take the impact.

michael adams

....