Drilling out a bolt

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Snowgoose-1

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Any tips woul be welcome.

Just a small grub screw that takes a 2.5mm Allen key.

It's in a jib furling halyard swivell . I have a kit to renew the two ball bearing races .it is rotosyay make. The grub screw holds the threaded cover to come off. Thanking many thanks.
 
anderson1947 said:
Any tips woul be welcome.

Just a small grub screw that takes a 2.5mm Allen key.

It's in a jib furling halyard swivell . I have a kit to renew the two ball bearing races .it is rotosyay make. The grub screw holds the threaded cover to come off. Thanking many thanks.
Click to expand...

Go carefully, it will be stainless probably. Use a proper drill made for SS such as one of these https://www.ebay.co.uk/p/DORMER-A10...m=201566094992&_trksid=p2047675.c100005.m1851
you will have to work out the size needed, pick a size that is smaller than the thread OD and then you can pick out the remnants of the thread and clean it up with a tap.
 
It's very easy to work harden s/s when trying to drill it out. And once you start there's no alternative left but to finish. I'd also expect it to be hard work to hold it steady whilst drilling too. If it were me I'd consider drilling it out as really the last resort and even then I'd hesitate.

Is it Alu s/s corrosion? I find boiling water can be quite effective. A mixture of Acetone and ATF to free up screws also gets a few supporters.

Also if planning to use a bit of grunt look seriously at getting a hex socket of the right size. As a tool they are a definite step up from trying to use an allen key.
 
Using a torx bit might give you the bite you need, heating with boiling water might help.
If you can get hold of links drill bits use that.
The heat developed while you drill might help the screw to let go, drilling in reverse can help the screw to get out.
It easier to center the drill on a Allen "head" go slow and use lube, start with small diameter.
 
No help to you now, anderson, but those stupid little screws really are a pain. The manual probably advises you to remove and lubricate them each year, but many owners don't notice/don't bother. Failing that, the best remedy is a SS thread insert...which you might end up with if you damage the aluminium. If so, you might look upon it as an improvement rather than a repair.
 
I'd have thought a small sized screw extractor would have a good chance of cutting into the existing hex socket and extracting - though use every possible heat/cold/plusgas option etc first.
 
On top of the work hardening that will occur by drilling, these items are produced by stamping, which is intended to work harden them for strengthening. My experience is that drilling them is very difficult indeed. You might need real heat to loosen them. A gas fired soldering iron comes with small heating nozzles that might be focused enough to only heat the grub screw and its immediate surroundings.
 
I had the exact same problem last year - and as I didn't ask here first I didn't know half the good advice that appears above. As a consequence I can say that if your efforts do result in damage to the fitting it is very easy to tap it out to the next size up and fit a bigger grub screw.
 
I have taken them out with a slot milling cutter held in a drill before now.
You can buy left handed drill bits which can work if you can reverse your drill as the setscrew may suddenly free off rather than constantly tighten
 
New cobalt drill bit, slow and lots of lube, it'll go through it like butter. Being an allen key should be enough to guide it, get a pilot hole in and end up with a bit 1mm smaller then the grub screw thread so 5mm bit for m6 screw, 7mm bit for a m8 screw etc. You should be able to tap the remaining parts out if it doesn't come out as your drilling with the heat and movement.

I would try an over sized torx bit hammered in with heat as others have mentioned, but most of the time drilling it out is easier and quicker then messing about trying to extract.
 
Yellow Ballad said:
New cobalt drill bit, slow and lots of lube, it'll go through it like butter. Being an allen key should be enough to guide it, get a pilot hole in and end up with a bit 1mm smaller then the grub screw thread so 5mm bit for m6 screw, 7mm bit for a m8 screw etc. You should be able to tap the remaining parts out if it doesn't come out as your drilling with the heat and movement.

I would try an over sized torx bit hammered in with heat as others have mentioned, but most of the time drilling it out is easier and quicker then messing about trying to extract.
Click to expand...
+1

and I would use a spotting drill for maximum rigidity. Very slow, steady pressure and thin oil.

https://m.ebay.ie/itm/KLOT-Solid-Ca...0-/322517541827?nav=SEARCH&varId=511495230251
 
Thanks to all.very helpfull .
Determined to have patience this time. Ordered mini butane torch and off to get the right drills.
 
bignick said:
This ^^^^

LH drill bits are amazing, but difficult to get hold of in metric sizes.
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One place I worked, we labelled LH drills as 'PZ2, PZ1 and PZ0'.
We used them to remove small countersunk machine screws which had been loctited in place as a tamper-evident fixing.

You sometimes see 'screw removers', which are a bit like a LH drill without the flutes, i.e. just the tip ground.

Another thing which works on loctited screws of various varieties is a suitable 1/4 hex bit heated with a blow torch or kitchen gas ring. Mind how you go, the magnetic bitholder will stop working above the curie temperature.... Use a bit holder with a spring clip in it.
 
If we are talking about those blasted hex nuts on the top of the rope cage, I gave up in the end and got an engineer to get that stubborn one out.

He heated the area up and the nut moved.

Apparently I had used the wrong type of LockTite, the type that sets like concrete !
 
fisherman said:
I think an easy out without drilling first, to leave as much meat as possible to avoid it spreading. You can always drill after if no go.
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The problem with that might be that the easy-out doesn't have sufficient depth of engagement to grip well. An easy-out of that diameter won't be very strong . If, as the OP says, the screw takes a 2.5mm hex key he could drill that size and the easy-out would go further in. The hexagonal hole would guide the drill; if it is not badly mauled.
 
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