Butchered Allen bolt

I've been thinking as I read the replies.The bolt is almost certainly locked in by corrosion.Nothing will remove it.Spark erosion is IMO the best bet.Is it possible to take the hatch off?Of all the tools suggested only Galadriel's appeals to me.Cutting through the washers is an interesting possibility but it's certain to inflict damage to the hatch or the teak below.Before attempting anything drastic the op should do his best to remove the hatch and take it to an engineers shop for spark erosion.Only if that is not possible should the removal tools be used.
 
Vara said:
Various people have tried to undo this, including me.

Too enclosed to cut a slot in it, dismounting and working on in workshop, difficult/impossible. Welding in situ outside my skill set.

Any ideas?

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I recently had a similar situation of a sheared bolt seized into aluminium. My solution was to use a very fine metal cutting disc ( cheapo version of a Dremel) and cut a fine slot in the aluminium in line with the bolt where it is seized in the aluminium. This enabled penetrating oil to do its job effectively. One of the other methods will then probably enable you to undo the bolt. I don't think that this small slot should compromise the strength of the hinge to an unacceptable degree.
It worked for me but admittedly the slot is not visible in my situation.
 
Thanks to all for the in put.

To answer a few points, the hole on the top of the ally was drilled to give an access point for copious quantitys of plus gas/acid to be injected.

The Allen bolt is seized to the hinge section, and rotates when the hatch is opened so its not seized at the threaded end,

5 similar bolts have with large amounts of heat/ hot air gun, have been successfully removed greased and returned to full working order, that was the last one and almost as soon as any pressure was put on the head it started to burr.

The hatch make is Nemo.

The hatch is useable at present, so will now leave as is, and have another go next winter.

Aluminium/SSteel interfaces are the work of the devil and should be banned.
 
Looking at the photo it looks like the shaft runs right through the hinge system to the other side of the hatch thereby carrying the spring as well. You don't say what is on the other end. In the photo, what is the small round mark on the top of the hinge, is it a grub screw?

Probably simplest as suggested elsewhere is to cut through the washers, remove lid and knock out the remains of the shaft as best you can. A small angle grinder with one of the very fine blades would do that simply for you.

Whatever way you do it you must soak it for days with a good penetrating oil, no not WD40. Mix up some acetone 50/50 with ATF or gear oil and use that. Cheapest and the best.

Must type quicker - you beat me to it.
 
SAMYL said:
Looking at the photo it looks like the shaft runs right through the hinge system to the other side of the hatch thereby carrying the spring as well. You don't say what is on the other end. In the photo, what is the small round mark on the top of the hinge, is it a grub screw?

Probably simplest as suggested elsewhere is to cut through the washers, remove lid and knock out the remains of the shaft as best you can. A small angle grinder with one of the very fine blades would do that simply for you.

Whatever way you do it you must soak it for days with a good penetrating oil, no not WD40. Mix up some acetone 50/50 with ATF or gear oil and use that. Cheapest and the best.

Must type quicker - you beat me to it.
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Thanks any way,all ideas gratefully accepted, the bolt and the central rod holding the spring are seperate, and the central rod can be pushed out when bolts at both ends are removed.

The thin cut with the angle grinder may well be the way forward but I have horrid visions of being left with the shaft left jammed in the hinge.

Financial penalties for rendering hatch unusable are pretty large as its a non standard size and would cost a fortune to replace.
 
OK. Assuming that the washers are plastic and therefore replacable, another idea would be to cut out the washers to allow the cover to slide along the bolt slightly or it should if it were not seized.

Soak with penetrating oil for as long as poss then with as much heat as you dare tap the cover hinges, with a wooden or plastic drift, so the cover will slide the few mms in either direction and eventually loosen up. A seized shaft will slide lengthwise easier than turning.

A sharp tap with a hammer on the rounded part of the aluminium where it is seized on the shaft may loosen the bond - but you risk marking the aluminium. Similar to loosening taper ball joints on car steering rods.

Best of luck.
 
Will hatch still work with plastic washers removed and shaft still stuck...yes.

Remove bolt and all washers from other end...replace bolt. Hack out washers at the offending end.

Heat and plus gas at offending end, welly with drift, if it works, job done, if it doesn't nothing lost.

By Jove Carruthers, I think we have a plan!!
 
Vara said:
Aluminium/SSteel interfaces are the work of the devil and should be banned.
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Another +1 on that.
Not really applicable in this case, but possibly of interest to some: for repairing or simply improving a steel into aluminium fixing a thread insert is often the best bet. The inserts are stainless, and as well as being stronger, they confine any corrosion to the interface between insert and aluminium. The interface between SS insert and and SS fastener suffers no such corrosion. (It might be susceptible to galling, but I've never encountered this with an insert). My preference is for the Recoil brand, rather then the ubiquitous Helicoil: it's a simpler and cheaper system.
 
The Allen bolt is seized to the hinge section said:
Agreed about the Ali / Stainless interface.
This may have been done to death by now but one more pennyworth if the bolt is indeed seized where the hatch should rotate around it. Part open the hatch, say 30 degrees and then drill a 3 mm hole through the hinge and the bolt head (perpendicular to the bolt ) and insert a drift (not a brittle drill bit) . Gently, very gently move the hatch up and down while soaking the bolt with penetrating fluid. This may well free the offending pivot. It might be worth doing the same at the other end of the bolt as well at the same time.
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Cleanest idea so far has been to open the hatch wide, cut the hinge on the hatch top along the length of the hinge pin with a dremel or similar. That should then free up the pin (you could always insert a wedge to open the gap). It would then be relatively cheap to get the cut re-welded and the hatch would be at close to it's original strength. The fix would be near invisible. Start to hammer on the hatch and you are liable to end up with chips taken out or cracks.
 
Yeah. But do yourself a favour an get a good quality one and not the China ****. They break off and then you end up with a broken piece of hardened steel in the centre of the whole mess :-((
 
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alahol2 said:
Cleanest idea so far has been to open the hatch wide, cut the hinge on the hatch top along the length of the hinge pin with a dremel or similar. That should then free up the pin (you could always insert a wedge to open the gap). It would then be relatively cheap to get the cut re-welded and the hatch would be at close to it's original strength. The fix would be near invisible. Start to hammer on the hatch and you are liable to end up with chips taken out or cracks.
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This is almost exactly what I did with my old Canpa forehatch many years ago. Used an angle grinder to cut the hinge open (nothing to lose!) on the 'blind' side & refilled with weld - very good end result & cheap too.

Edit: 'almost exactly' - well you know what I mean :D
 
Is the bolt stainless ?
If it is stainless, then stainless and aluminium react together and fuse.
I think it would be best to remove the hatch completely in order to work on it in a workshop situation, which would be more comfortable, and more eficcient.
 
Vara said:
Thanks to all for the in put.
The Allen bolt is seized to the hinge section, and rotates when the hatch is opened so its not seized at the threaded end,
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Doesn't that also mean that it is no longer threaded at the threaded end? Otherwise it would move horizontally as the bolt unscrewed and jam the hatch. If that is the case then there doesn't seem to be much point trying to remove it.
 
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