Butchered Allen bolt

Just drill it out in situ.
Bit of care with a thin blacksmiths drill first. Then gradually increase in size.
Bolt looks soft enough to drill.
But an impact driver may do the trick first
To renew re tap to a slightly larger size
 
Rossynant said:
However the bit is called in English (heard an "easy-out" ;) ) there is a special tool to get damaged bolts out, looks just like threading tool with opposite thread - you just drill small hole into the screw and the tool having opposite thread screws into this while unscrewind the bolt. Ask some machinery shop, this is used on rusty engines and such.
Click to expand...

I once broke one of these off in a thread on my prop the only way to get it out was by using a spark erosion machine. Not something that you can do in situ, use the largest one you can and be very careful.

I would use plus gas or another releasing fluid on the bolt and leave for a few days before trying to use the extractor, obviously you will have to mask off the teak. Standard WD 40 is not a releasing fluid so don't waste time with that. However they do have a version http://www.halfords.com/webapp/wcs/..._productId_874567_langId_-1_categoryId_255223 not used it always used plus gas so don't know how good it is.
 
Yup, would shy away from any stuff I don't know ingredients exactly; on aluminium diesel or kerosene works, can be mixed with bit of thin oil also. Found 3-1 working too.
Extracting tool should not be cheapest available, important to have one of proper steel (as with any bits). To loosen the thread good idea is to pour hot water on just before unscrewing - aluminium expands more than steel initially.
 
Being pessimistic I would say that unless the impact driver fails to answer, and drilling is not an option then you probably won't succeed with anything. Is removing the whole hatch an option or are there fastenings under the bit you can only remove after shifting that bolt?

Stud extractors (easy-outs) are borderline laughable in my opinion, especially if the bolt is seized enough to strip the head.
 
I guess the bolt is not right through to the other hinge if so can it be drilled out from the other end ?

If it came to having to destroy the hatch, as a last resort I would try to arc weld a short piece of steel pipe onto the bolt head down the middle of the tube to extend it to a better position to unscrew the heat may help to loosen things up and would be very localised. Good luck
 
Drawing on 20 years working in the tool business (Snap-on-Tools) none of the left hand thread extractors are particularly successful. The reason for this is because the metal is such a high carbon content they break easily. On many occasions I had to explain to a mechanic that they were not covered by the Snap-On-Tools warranty.

If that bolt is stuck because the stainless steel bolt is corroded into the aluminium, there is not a lot of hope of getting it out. The only tool I would try is one of these sets:

http://buy1.snapon.com/catalog/item...675450&supersede=&store=snapon-store&tool=all

A bit sad, even after 15 years out of the business I still remembered the part number!

The way these work, using a drill bit from the set, you drill a hole as large as you can into the bolt (or broken stud), you then tap in one of the matched fluted shafts. Each fluted shaft has a 'nut' which fits the shaft and provides a fresh hexagon for a socket to fit on. Follow the advice already given before using the E1020, use plenty of releasing oil. The one major benefit of the E1020 is that because it is a shaft and not a left hand thread, you can work the bolt back and forth ever so gently until enough lubrication works its way into the corrosion.

If this does not work, nothing will. Good luck
 
I would go for a (cheap) torx bit that was just too big, heated with a gas flame until it's very hot, hammer it in, apply oil (plus gas ,red diesel?) while it's hot, apply torque with suitable adaptor to t-bar.
Another alternative is left-handed drills, these work very well on smaller sizes that have been 'permanently' loctited.
 
I would use a recepricating or jig saw or maybe a dremel with a blade, or possibly a Bosch sander with vibrating blade to cut though the washers (they look plastic in the photo) either side of the hinge lugs, remove hatch out of the way, then drill and retap the last bit of the bolt hole. Hard to tell, but is there a hole for a grub screw preventing the bolt moving showing in the photo ?
 
SpottyDog5 said:
I would use a recepricating or jig saw or maybe a dremel with a blade, or possibly a Bosch sander with vibrating blade to cut though the washers (they look plastic in the photo) either side of the hinge lugs, remove hatch out of the way, then drill and retap the last bit of the bolt hole. Hard to tell, but is there a hole for a grub screw preventing the bolt moving showing in the photo ?
Click to expand...

I'm with you cut through the nylon washers and put it on the the bench to sort it.
 
Is it a through shaft? If so just cut it wherever you can.

I would hazard that no thread extracting device will grip what is left of the head. Consequently you are left with:

- Get a small metalworking cross-cut cold chisel and cut a square socket in the remnants of the head. You need one with a chamfer on only one side. Then use a square bit in an impact driver.
- Drilling it out. A pain, but with top quality bits so they don't snap and great care, you will succeed.
- Friction welding a bar to the socket. Probably not strong enough to remove the bolt anyway, but could be worth a try.
- Spark erosion. You would either have to remove the hatch or pay more than its worth.


If chiseling didn't work I'd drill next, if I couldn't saw through it...


Don't use cheap allen keys or the wrong size. Good ones *never* strip the head, they'll snap it off first...
 
Bobobolinsky said:
I'm with you cut through the nylon washers and put it on the the bench to sort it.
Click to expand...

+1

That would be my preferred route. The bolt is almost certainly seized in the alloy frame. (why else did the head get chewed? )
If you were to get something into the old hex socket firmly enough- it may even twist off rather than unscrew?
If you chop the bolts through the nylon washers either side of the hatch, you leave a nice tidy surface of the old seized bolt in the frame, and lift off cleanly.

I'd invest in a really decent centre punch and a set of Cobalt alloy twist drills. Get a good centre mark in the old bolt and start off with a small hole, drilled gently with plenty of oil. Work up sizes slowly until you can peel out the remaining thread of the old bolt.
If you have done this centrally enough, you could probably just run a tap down the threads in the frame to clean it up?
If not, there will likely be enough meat tin the frame to drill & tap to the next size up. You may have to open the hole in the hatch hinge by a mm or so? for a new oversize bolt.
Should you not be keen on trying the tapping / re-tapping yourself - take the lot to a machine shop and explain the problem?

Accurately drilling out stainless bolts in aluminium alloy is not the easiest job..

Graeme
 
Loctite? Torx heads? Slots? Forget it. The odds are the aluminium has corroded and locked in the fastener. Wild horses won't get it out (but they'll have a frustrating time trying). Drilling may be possible if there's a good centre. Spark erosion, as suggested, is the best remedy, but will probably be impracticable in situ, and expensive. However, it's maybe worth the OP asking a specialist. Googling 'mobile spark erosion uk' gets plenty of hits. But I think that hatch has to come off (or live with a mangled bolt head so long as serviceable). After all, if it ain't actually broke...
 
You must log in or register to reply here.

Share this page

Top