Seized countersunk socket head screw

LadyInBed

LadyInBed

Well-Known Member
Joined
2 Sep 2001
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Me - Zumerzet Boat - Wareham
montymariner.co.uk
There are four behind my Whitlock wheel, three came out with some difficulty (they have been undisturbed for best part of twenty years) but one managed a quarter turn and refused to move any more.
I put quite a bit of force on the alan key which looks like it has distorted the (A2) socket head.
How should I go about trying to get it out?
The screws hold on a plastic (of sorts) cover, so I think heat is out.
 
Firstly apply some release penetrant spray, which is what you should've done before you even started trying to turn any of them. Leave it for a while before continuing.

Then turn it back in a bit before trying to back it out. If the hex head is already rounded you can use a screw extractor bit, which should work well on hex heads, or more generally a Dremel with a cutting wheel to cut a slit into the head and then apply a large and well fitting screwdriver - that one works on any type head.

If the head is broken off entirely, you'll have to drill it out, which is a total pain in the ass with stainless screws.
 
If the Allen socket is too rounded to be able to use an Allen key, the easiest thing is to use a reverse thread extractor or drill it out if you have access. I would probably go for the drill as Allen keys are very easy to drill out as the head is self centreing. Just choose a bit which is the same size as the threaded part of the Allen bolt and drill into the head until it falls out. The stud should then be easy to get out using pliers once you have access.

If it's stainless steel the use a cobalt-type HS drill. It's like a knife through butter.

Richard
 
As I said in another thread, adjust size as required...
nigelmercier said:
... Of course all but one of the 4mm head Allen Screws were seized solid and soon became rounded, so I started to drill them out using a 5mm drill. At this point I had an idea, and hammered a TX30 Torx bit into the 5mm hole: it worked perfectly. A handy tip I think.
4mm-Allen-Screw-Rescue-with-5mm-drill-and-TX30.png
Click to expand...
 
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Yngmar said:
Firstly apply some release penetrant spray, which is what you should've done before you even started trying to turn any of them. Leave it for a while before continuing.
Click to expand...
Ah! The beauty of hindsight :)
Will release spray track horizontally along a 2 inch screw? Especially as I can't get it past the countersunk head.
If the hex head is already rounded you can use a screw extractor bit, which should work well on hex heads
Click to expand...
Thanks, I will also try that.
 
The torx is a great tip :)

If that fails and the item being bolted through is thick enough to allow, it's sometimes easier to remove the heads and take the item off, then deal with what's left.
Drill into the socket with a bit slightly larger than the thread diameter, but smaller than the head, when the head starts to spin on the drill, stop. When you've done them all, take the item away. This takes the clamping pressure off the threads. Soak with some penetrating oil, grip with a good set of mole grips or similar and unwind them.

As I said, this only works if the item being bolted through is thick enough to leave some of the shank. If you're at the point where you are going to be drilling them out, you haven't got much to lose anyway
 
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prof pat pending said:
If that fails and the item being bolted through is thick enough to allow, it's sometimes easier to remove the heads and take the item off, then deal with what's left.
Drill into the socket with a bit slightly larger than the thread diameter, but smaller than the head, when the head starts to spin on the drill, stop. When you've done them all, take the item away. This takes the clamping pressure off the threads. Soak with some penetrating oil, grip with a good set of mole grips or similar and unwind them.

As I said, this only works if the item being bolted through is thick enough to leave some of the shank. If you're at the point where you are going to be drilling them out, you haven't got much to lose anyway
Click to expand...

Good advice from the Prof ..... and see post #4 for confirmation. :)

Richard
 
LadyInBed said:
Will release spray track horizontally along a 2 inch screw? Especially as I can't get it past the countersunk head.
Click to expand...

Yes, if you spray a bit on a dry surface you can see it spread rapidly in all directions, including upwards. If there's any crevice, and there usually is, it'll find it and creep in.
 
Had a similar problem in my Jeanneau, trying to unbolt the engine control box. S/S allen head bolts into aluminium! Disaster looking for somewhere to happen.

Had to drill out the heads after the screw remover failed completely to deal with it. Lots of drilling and then when I'd removed the head, the cover came off and I was able to grip the shank and with the use of a hammer! eventually got it out! Three days effort.

Replaced the system by drilling out all the holes and using a proper s/s nut and bolt and washers, to re-clamp it, liberally smothered in anticorrosion paste all over AND making sure that all metal-to-metal surfaces were insulated from each other by plastic washers and PTFE tape on the threads inside the box.
 
PotatoNavigator said:
Small impact driver can help a lot, I have a 10V Makita one that's brilliant.
Click to expand...
Impact driver looks like a good first approach as it doesn't destroy anything.
Though the problems that I foresee are:
finding an adapter to go from an Alan socket to my impact driver (which I think is 3/8 hex socket)
and bracing the Binnacle, probably against the saloon bulkhead, to absorb the impact, though that may be a bit OTT.
Though I might have to take the Compass off first !!!
 
A lot of bit sets for impact drivers come with an adapter, this is the set I have:

http://www.screwfix.com/p/erbauer-impact-screwdriver-bit-set-32-pieces/12492

LadyInBed said:
Impact driver looks like a good first approach as it doesn't destroy anything.
Though the problems that I foresee are:
finding an adapter to go from an Alan socket to my impact driver (which I think is 3/8 hex socket)
and bracing the Binnacle, probably against the saloon bulkhead, to absorb the impact, though that may be a bit OTT.
Though I might have to take the Compass off first !!!
Click to expand...
 
LadyInBed said:
Impact driver looks like a good first approach as it doesn't destroy anything.
Though the problems that I foresee are:
finding an adapter to go from an Alan socket to my impact driver (which I think is 3/8 hex socket)
and bracing the Binnacle, probably against the saloon bulkhead, to absorb the impact, though that may be a bit OTT.
Though I might have to take the Compass off first !!!
Click to expand...

Rather than an impact driver (I.e. as used with masonry bits), do you have access to an electric rattle gun? I have a tiny 9V Makita hex drive with a rattle function, which is astonishingly effective at removing corroded fasteners. Less brutal than an impact driver, too.
 
macd said:
Rather than an impact driver (I.e. as used with masonry bits), do you have access to an electric rattle gun? I have a tiny 9V Makita hex drive with a rattle function, which is astonishingly effective at removing corroded fasteners. Less brutal than an impact driver, too.
Click to expand...
I've not heard of a rattle gun, I will investigate.
though maybe PotatoNav alluded to it in #11.
Thanks.
 
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