Do anyone have any good tips for

[julians]

removing a screw whose had has benn rounded.

 

Its a sunken screw with an allen key type head

 

 

Ta

 

Julian

[Dave H]

It depends how brutal you can be. Try using an old screwdriver with a (slightly) sharpened end and hammer it into the screw until it provides sufficient purchase (i.e. creates a slot). You could file a slot into the screw to get a flat blade in. Or you could try drilling it out.

 

Good luck

[Peter Lydford]

weld the allen key to the screw teeth.gif

 

 

[Fast Westie]

Julian

You could drill the head off and remove the stud with a pair of pliers

 

 

[julians]

I cant file a slot into it because its sunken, I think I'm just going to have to plump for the drill.

 

 

[aideen]

Depending on how large and accessible the screw is, you might be able to find an ordinary bolt whose head just fits in the hole (maybe with persuasion!). Then use a spanner or mole grips on the bit of bolt head still protruding.

 

Aideen

[Simos]

Hi Julian,

before drilling the bolt out proper you can try a set of stud extractors (couple of quid from Halfords). Drill the appropriate sized hole and tighten the extractor in, the sharpened left hand threads should bite and unscrew the bolt. If it fails you can still drill the bolt out

 

Cheers, Simon.

[julians]

I think I'll try and get hold of some of those stud extractors first, thanks for the tip.

 

Julian

[Rory McLeod]

Oversize alan key ground down at the end to overmatch the rounded hexagon, 'bang' it into the rounded hole (serves to break the thread friction also).

[Rob Morris]

CAUTION! Screw extractors are okay if used with care. They are made of harden steel often HSS (high speed steel) if you twist too hard they will break, sadly your average drill will NOT be able to drill the remains as it too is made from HSS. My suggestion is to drill off the head first which will reduce the tension with the bolt, then use the scew extractor to remove the remaining stud.

 

If in doubt please please phone me as the wrong move could prove VERY costly. Trust me I'm an engineer!

 

If you live near Shropshire I will glady assist with the removal, as the problem of damaged bolts is often made worse buy poor attempts at removal.

 

If you make a mess at this point you may face removal of the whole unit (i.e. engine for transportation to an engineering workshop for spark errosion at (£25 / hour), minimum 4 hours including setting up machine!!!!!

 

Don't want to put you off but take it steady, or phone a friend.

[Paul D Jones]

Hello Julians

I agree with Rob the stud extractors I have used at work in engineering have been worse than useless and have caused more work you do not say what the bolt is stuck in. If it is in something removable from the car do so and drill it out in an engineers pillar/table drill first using a centre drill then a drill that will remove most of the old bolt then you may find the thread will collapse and come away with the drill bit. If the bolt head is assessable and tapped into aluminium try warming up the aluminium up with boiling water at fist then try turning the bolt as the aluminium will expand a little faster then the steel bolt don’t use a flame type heat unless you know what you are doing [the fire brigade No. 999 ] To try and loosen the bolt you can try hitting the head with a good quality pin punch this will stretch the bolt a little and my then loose it grip and then you may again be able to remove it if it is in something solid you can hit it quite hard not hit you thumb I spent 4 hours waiting in A+E after I trapped my thumb in the lorry compound gate luckily on pay before they just drilled a little hole and let the black blood out what relief If you want you can E-mail a photo to me and I will help you more if needed also Iam in Grimsby and also help if you get stuck if Iam nearer to you I go back to work New years day so specialist equipment is had to come by until then.

 

Hope it turns out ok no pun intended Paul Tel 01472 590325

 

 

paul

[julians]

thanks for the answers, its not actually critical that I remove it now, it is a screw that holds the spark plug cover in place on the engine rocker cover. So I only need to remove it when I come to have to change the plugs.

 

After much consideration I think I'll start witha small drill bit and progressively work my way up in size until the screw collapses. I cant see this doing too much damage, unless I drill too deep and go through the rocker cover.

 

I will try first with an odd size allen key and se if I can force it, although I have a sneaking suspicion that it wont be able to get enough purchase on it.

 

Julian

 

 

[CHRIS CLARK]

Thought at first you might be refering to the allen bolt that goes into the blind hole (on my car anyway) & locates the lower damper mounting to the lower wishbone.

 

Mine had seized on both sides and they were a s*d of a job to remove!!!thumbsdown.gif thumbsdown.gif thumbsdown.gif

[Super_Rich_Bernie]

I wish I had read the advice on the extractors (Easyout, i think they were called) before I attacked the brake caliper of a 1950s Bristol with one.

 

I snapped off the extractor, the part was scrap, and a new one was found after a long search, costing lots of money.

 

There are some rather better extractors, available from Holden Vintage & Classic amongst others, which work in a reversible drill.

 

Often the heat from the drill and the anticlockwise action bring the bolt out before the 'extracting' action. Hard to explain, but they work well and I haven't heard of them snapping off.

 

They cost about a tenner each, I think.

 

cheers

 

Jonathan

[J.R.]

Short,simple & uncomplicated methods are always the best.

 

To remove countersunk screws with damaged heads (e.g. brake drum retainers) use a hammer & centre punch applied tangentially at the edge of the fastener / casing, - works every time for me.

[Simos]

Hi Julian,

Rob is quite right I should have attached a health warning with the stud extractors. I have broken them before but have always got the bit out without too much effort (lucky) as it's been a "new" jam rather than a rusted in over time kind of jammed in (that's my interpretation !) However I've also got out bolts I couldn't shift otherwise and would have been difficult to drill out - so they do work sometimes (though people have had worse experience than me obviously).

 

I think my unconscious plan is to soak it with easing oil if I have the time, warm it, use percussion to vibrate it (hit it with a hammer)use an off-size tool to _tighten_ it slightly which quite often free's it but doesn't do any damage to the untightening faces of the bolts so i don't care if I round them. Cut a slot and use a large screwdriver, lots of pressure and a spanner on the shaft to turn it. If not the above then drill a hole and use a stud extractor but with care not to break it in the hope it was a bad grip on the head which has caused the whole problem rather than a seized-completely-solid-and-will-never-be-moved thread. If that proves to be the case then we're drilling the puppy out.

 

Cheers, Simon.

[Pierre Gillet]

Use Transyl, it worked for me several times. a "miracle" ease fluid !!!

[Rob Morris]

Additional thought for removing your bolt! As it is situated in full view with easy access, I would suggest that you form a small barrier around the head from plasterscene / blue-tak (not sure about spelling. Next apply loads of "Plus Gas" and leave it to soak in over night. Once fully soaked suggest that you find a friend with an impact driver with either the correct size hex bit or willing to machine a lead on a larger item! This should then be used to attempt the removal of the screw, a couple of firm taps will idicate sucess or not.

 

Should you have to resort to drilling, then I would suggest that you first start with a drill, small enough to fit within the natural socket head of the screw but not too small as you may break the thing which would prove as bad as the extractor this firaast drilling should aid you to keep the hole square which could prove important latter on! Once you have drilled 10mm approx. of the screw then I would swop the drill bit for one of a suitable diameter (i.e. slightly larger than the diameter of the screw shank)and drill off the whole head, this will release the cover and leave aximum shank visable for extraction.

 

From hear you can either attempt to use the extractors as the pressure will have been release with the removal of the head (screws are only in tension between the threads and the underside of the head)or you could attempt to continue drilling the core of the bolt! Only concern with this option is that if your drilling practice is not very square to the screw shank then as the size of hole expands so does the error!! Quite often the result is that no engineers do not know when to stop and will discover that they have lost direction and the drill has found the soft aluminum of the head oppossed to the high tensile steel of the bolt. Minimum fix for this would be an helicoil insert for £10, maximum repair could be welding or new head!

 

Again any concerns please phone me first (01952) 501467.

[julians]

OK, problem sorted, drilled off the head of the screw (which literally flew off witha loud pop), and then managed to extract the rest of the screw with some pliers.

 

Cheers for the advice.

 

Julian

[CHRIS CLARK]

Obviously you chaps using the 'hammer & centre punch' etc. haven't tried that lower damper mounting. It's recessed by about 5mm with a o/d of about 8mm!!!!!!!! Nightmare job.

 

The thing is, once extracted, you want to put grease on it to make future removal easy, but as it holds the damper (shocker) you don't want it backing off!

[Michael Peterson]

The cure for high speed steel is to either heat it cherry red and allow it to cool slowly thus softening the steel (this is rarely practical or possible) or simply buy a cobalt bit which will easily bore through HSS.

[Rob Morris]

Michael Peterson, Do you intend for him to anneal or normalise the HSS? Either of these in this case would have caused great distress to the alloy parts when you consider the coefficient of expansion and the thermal conductivity of a high chrome steel against aluminum alloy!

 

Additionally the crude carbie drill (masonry style) will as stated drill HSS but the control of the hole diameter and associated damage would be very risky in this situation. I have actually got a set of solid carbide drills manufactured for drilling precise holes in Stellite (very, very hard carbie based material, depending on grade), but would not of recommended them for this application just in case as these would prove almost impossible to remove without spark erroision.

[ian]

A tip I heard recently is to repeatedy blob weld onto the top of the screw until there is enough metal there to get mole grips on......may be a bit drastic in this case.

[Matt Prior]

An unrelated screw warning. I couldn't get the drain screw out of my broken boiler (on Xmas Eve, conveniently), so just removed the larger thermostat-housing-bolt to drain the system (and save a £120 call-out charge from a plumber).

 

My advice: please make sure the water is turned off from the header tank in the loft before you do this, as its pipe may not go through the airing cupboard with a valve, like I erronously thought mine did.

 

Otherwise, you're in for hours of fun.

 

Classic moment for me was holding a full bucket of filthy water in one hand, with a finger of the other hand plugging the boiler, realising that I had couldn't get back to the garden to both empty the current bucket-load AND retrieve the plugging bolt which I had emptied onto the lawn with the previous bucket-load of filthy water.

 

Frank Spencer, Lee Evans and Victor Meldrew combined couldn't have done it better.

 

Still, saved a £120 plumber's call out charge.