Seized screw in tap

Any ideas? Not my doing but one of the screws in tap is seized and head destroyed. (see image) I have carefully tried various cross head bits and needle nose pliers. I have currently sprayed with lub to soak overnight. Access is not good as it is recessed by 12mm and the dimaeter of the access point is 12mm.
My next attempt would be to drill out but want to leave that as a last option. So any other ideas to explore first?
https://imgur.com/ZAjiiIG

On 02/12/2019 20:54, ss wrote:
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Made harder by being sunken in the shroud... You might be able to create a couple of flats on either side with a needle file, then get pliers on it. You could also try some thermal shock - hold a bolt with pliers, and heat the end blow torch and then push it onto the end of the screw for a bit before trying to turn it.
Personally I would probably try an anticlockwise drill bit just slightly larger than the size of hole already in it. It will either grab and spin it out, and if not, it will take the head off, meaning you can remove the tap handle and then worry about the shank of the screw after.

On 02/12/2019 21:19, John Rumm wrote:
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Not possible with the limited access.
You could also try some thermal shock - hold a bolt with pliers, and
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Will give that go tomorrow
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I dont have an anti clokwise bit.
It will either grab and spin
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If the above fails I may try using a small drill bit to drill our a couple of slots. The screw is brass so possible.

On 02/12/2019 21:39, ss wrote:
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You can get sets quite cheaply if you search ebay for "left left handed drill bit"...

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Or the other kind of thermal shock: "rust shock" is (a class of) sprays tha combine pentration oil with a freezing spray.
Thomas Prufer

On 02/12/2019 20:54, ss wrote:
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The larger picture appear to show that there is some of the cross head left. I have a cross head screwdriver where the point of the cross head has been filed off so it doesn't bottom in the screw head when attempting just to catch on the edges where remnants of the cross head may give the screwdriver some grip.
If drilling - use a drill with a larger diameter than the head of the screw and JUST drill the head off - leave the rest of the screw intact. You should than be able to remove the tap head and have the rest of the screw standing proud of what it is screwed into with easy access to use mole grips to get it out.

On 02/12/2019 21:26, alan_m wrote:
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Its more an impression from the shadows nothing of the crosshead left. I will try and file a bit though and give it a go.
I am only trying to save the taps as a neighbour wants them from when I replaced my bath with a shower tray.

On 02/12/2019 21:26, alan_m wrote:
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I'd have little hope of that working, similarly I have had little success with the anticlockwise recovery tools.
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That's exactly what I would do.

On 02/12/2019 20:54, ss wrote:
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Impact driver

On 02/12/2019 22:00, The Natural Philosopher wrote:
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Dont have one but could I suppose try using cordless drill on hammer, has worked before for me. OR if needs be use a crosshead bit and thump it with a hammer.
I will look at all suggestions and go from gentle to not so gentle and then destructive, assuming if I destroy the screw head then the shroud will come off and then can tackle the remains of the screw, which by then will give me better access.

ss brought next idea :
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Simple, drill the head off, which will allow the handle to be removed, the there will be some thread to grip with a self grip wrench, to remove the remnants of the screw.

On 02/12/2019 20:54, ss wrote:
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If you have a multitool and a narrow blade that will fit in the hole - cut a new deep slot in the screwhead and wind it out with a flat bladed screwdriver.

On 03/12/2019 10:20, Andy Bennet wrote:
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Not enough space for multi tool.
Update:...........
I eventually drilled off the screw head and had another screw that fits from an old tap, so problem solved.
As it turns out the reason it was seized was the screw was actually bent and had been forced home, the new screw works ok so the threads have not been damaged.