How to remove coach bolts

[Murmansk]

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.

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?

[Bob Minchin]

Weld a bit of L shaped bar to the head to act as a handle then cut it off to do the next one and so on?

[2987fr]

Murmansk [e-mail] wrote

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

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.

[2987fr]

Screw extractor.

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[Harry Bloomfield]

Murmansk has brought this to us :

Centre pop the middle of the dome, then drill into it with progressivly larger drill bits, to the thickness of the thread. The dome will then come free and the rest of the bolt pulled out. It the head tries to turn as you drill, clamp the nut with a mole grip.

[michael adams]

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

...

>

[Nick Odell]

Altogether, one, two, three: ANGLEGRINDER!!!

Seriously - and maybe this is what Jim was thinking of - could you slice through the timber with an anglegrinder in such a direction that inserting a new splint of wood will give the structure its strength back and also cut through the shaft of the bolt in such a place that you can pop each severed half out of there? Beware of metal sparks setting dry timber on fire!

Nick

[michael adams]

[tabbypurr]

The mains methods are already mentioned. A couple more: Use a left handed drill bit into the head & put ATF on the nut to make it come free easier.

NT

[Bill Wright]

Cut across the thread level with the visible face of the nut, using an angle grinder with a thin wheel. Cut the nut in half by cutting into the bolt end and thus the nut, at right angles to the previous cut. Stop short of damaging the wood. Break off the halves of the nut using a cold chisel. Bash the end of the bolt so it retracts. If this isn't enough to make the head grabable bash it some more using an old bolt or something (and a hammer).

Bill

[Brian Gaff]

Grind the head off down the hole and get new bolts?

Is there any spare threaded part blow the nut you can use a pair of moles on? If its really rusted up there may not be any other way than to cut the bolt itself by the nut, sadly either way if you intend refurbishing it next time find some galvanised or stainless bolts. Brian

[Brian Gaff]

That is not going to work as the wood would char.

Brian

[Brian Gaff]

A friend of mine,no longer with use called it his bodger...

However a lot of coach bolts tend to be quite soft and it won't work very well.

Brian

[Tricky Dicky]

Very often you can get the squared end to re-engage with the wood by hammering the domed end further into the wood. The only problem might be if the nut is badly rusted on it will simply start to turn again once any torque is applied. Worth a try along with a good dosing of easing oil on the nut, you will not be in a worse position if it does not work.

Richard

[Brian Reay]

Just drill into the head using a drill slightly larger in dia than the bolt. (You will need a centre punch, may be a pilot hole.) Once you've drilled through the head, it will part company with the rest of the bolt.

[Robin]

...and possibly in a _better_ position - to cut the bolt above the nut and then drive it out

[Ian Jackson]

In message [e-mail]>, michael adams [e-mail]> writes

I've never used a nut-splitter before. Even if it doesn't actually crack the nut, I guess that it might distort it slightly (especially if used repeatedly at several angles) and break the rust in the threads - allowing penetrating oil to get in better.

[Thomas Prufer]

But why? Cut a slot in the head, insert screwdriver in slot, hold head while recessed nut is turned by the socket...

That. And sparks hitting glass and burning in...

Thomas Prufer

[Thomas Prufer]

Ah, I geddit now: The head is down the hole...

I'd stick a flat screwdriver down the hole, and try to wedge it between the edge of the domed head and the wall of the hole, in the hope that the nut won't need a lot of torque to come off.

Thomas Prufer

[Murmansk]

I'd stick a flat screwdriver down the hole, and try to wedge it between the edge of the domed head and the wall of the hole, in the hope that the nut won't need a lot of torque to come off. <<

OP here

Both ends of the bolt are recessed down 3cm deep holes. I've tried the above with no luck.