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>> Home > Forum > General Resources > Allen Screw Removal
Allen Screw Removal
(892 views)
Author Message
onetenor
(Fleet Admiral!)





Forum Posts: 461
12th Nov 2018 22:34  
>> Permalink
mdlbt.com/47985

I have some 3Mm bolts/screws with allen heads. The sockets have almost totally rounded out so can't remove them. They are pocketed (recessed) so can't grip them with anything. Drilling heads out seems to be the answer as welding would damage the surrounding alloy. What does anyone suggest I should use. Drills,burrs,mills etc ??????👍

teejay
(Commander)





Forum Posts: 47
12th Nov 2018 22:46  
>> Permalink
mdlbt.com/47986

Hi onetenor normally I would suggest stud/screw extractor/ but I would suggest that you drill it out using 2mm drill then if you have an tapered burr you could try and catch the screw with that, I managed it once, or you could drill it out with 2mm drill then use a smaller burr and carefully grind the screw out and if successful re-tape the hole for 4mm screw

RNinMunich
(Fleet Admiral!)





Forum Posts: 2483
12th Nov 2018 23:25  
>> Permalink
mdlbt.com/47987

Mornin' John,
I assume this is on the cylinder head you mentioned?
If so I would hesitate to use any of the extractor methods in case it distorts the ally head.
I would be inclined to to use a flat ended milling bit to carefully mill the heads off, until you can gently prise the head off.
When the head is off you can probably grip the threads with pliers and get 'em out, soak with penetrating oil / WD40 overnight first perhaps!?
Using an HSS drill bit might also be OK, but with more risk of drilling into the head and/or spreading the shank of the bolt over the lip of the bore hole. Making it very difficult to lift the head off.
A milling bit in a decent drill press or mini milling machine (like my Proxxon) would be my choice.
Cheers, Doug 😎


Young at heart - slightly older in other places 😉 Cheers Doug
Colin H.
(Fleet Admiral!)





Forum Posts: 432
13th Nov 2018 08:18  
>> Permalink
mdlbt.com/47988

Doug your right as usual, but prior to soaking in penetrating oil I would gently warm up in the oven and then apply the oil so that it gets drawn in as it cools.
Cheers Colin.


Fair winds and calm waters,
COLIN.
steve-d
(Lieutenant)





Forum Posts: 45
13th Nov 2018 08:31  
>> Permalink
mdlbt.com/47989

before resorting to milling/drilling I would get out my box of assorted screwdriver bits. In there I have an assortment of metric hex, imperial hex, spline, torgues, etc.
Find something that is too large and (gently) hammer it into the bolt head. You could even grind an oversize down to fit which would give a sharper edge to the hex which will help it grip.

Steve

RNinMunich
(Fleet Admiral!)





Forum Posts: 2483
13th Nov 2018 08:42  
>> Permalink
mdlbt.com/47990

Good idea Colin 👍
Think you already tried the 'hammering' method didn't you?
I got the impression from you that there wasn't enough hex form left for that to work!
Cheers, Doug 😎
PS The fact that someone rounded out the hex heads suggests to me that the bolts might be seized in anyway 🤔 making success with improvised tools unlikely.


Young at heart - slightly older in other places 😉 Cheers Doug
steve-d
(Lieutenant)





Forum Posts: 45
13th Nov 2018 09:04  
>> Permalink
mdlbt.com/47991

If there is nothing left to grip in the holes I would next try a left handed drill. The vibration, heat and left hand direction may unscrew the bolt.
Which ever direction drill you use the hole in the bolt head will keep it centred. Start with a smaller size and drill deep enough to be just below the head. Go up a size and drill again but don't get to close to the bolt thread diameter. Your ideal situation will be that as you get close the head will snap off. You could drill close then drive a screwdriver bit in and use that to snap the head off.

Steve

onetenor
(Fleet Admiral!)





Forum Posts: 461
14th Nov 2018 23:38  
>> Permalink
mdlbt.com/48015

Thanks chaps. All good ideas some of which will try. It has to be remembered I am chair bound so working "a la main"so to speak. Heat and oil /cooling has been tried. A very hot radiator to hand LOL. about 85 C. I think ball burrs could be the answer. They will cut through stainless.Eventually. Keeping flat mills central may be hard without a press of some sort. No current access to left handed drill unfortunately. I'll get there one way or three.😁👍

onetenor
(Fleet Admiral!)





Forum Posts: 461
15th Nov 2018 00:01  
>> Permalink
mdlbt.com/48016

Trouble is I can't access all my bits just now or I might try tapping in a spline (or two).On big stuff I would throw down a weld until I could grip it. Anyway a chance to use my new Mini Drills. Thanks again to all.👍 BTW Ste the bolts have a plain shank so no danger of thread damage.😜

RNinMunich
(Fleet Admiral!)





Forum Posts: 2483
15th Nov 2018 01:39  
>> Permalink
mdlbt.com/48025

"the bolts have a plain shank so no danger of thread damage"
Well John, in THAT case you're laughin' 😁
Run an HSS drill up 'em (They don't like it up 'em you know! 😲As Cpl Jones would say😉) as mentioned above, the remains of the hex will keep the drill centered. Start with a small pilot hole perhaps.
Good luck, Doug 😎


Young at heart - slightly older in other places 😉 Cheers Doug
onetenor
(Fleet Admiral!)





Forum Posts: 461
15th Nov 2018 02:05  
>> Permalink
mdlbt.com/48027

Much as i thought Doug Ta!👍

Ianh
(Sub-Lieutenant)





Forum Posts: 15
17th Nov 2018 13:44  
>> Permalink
mdlbt.com/48088

Try using a left handed drill I have a couple from Tracey Tools Devon. Very Useful


Only old in years not mind or soul.
BOATSHED
(Fleet Admiral!)





Forum Posts: 102
18th Nov 2018 23:40  
>> Permalink
mdlbt.com/48129

You could always try super gluing a near as allen key into it and then try undoing it. If it doesn't some out you can remove the allen key with deactivator before you try anything else that would damage it too far. Or try using a Dremel tool and cut a slot for a screwdriver.


BOATSHED
onetenor
(Fleet Admiral!)





Forum Posts: 461
20th Nov 2018 22:29  
>> Permalink
mdlbt.com/48155

Thanks Boaty but can't slot them as they are deeply recessed. I don't think any glue will work either even the plastic steel I have.👍

nick
(Seaman)





Forum Posts: 2
21st Nov 2018 08:46  
>> Permalink
mdlbt.com/48172

I know it is a long shot but what you need is a spark eroder.
Regards, Nick.