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12th Aug 2012, 12:00 am | #1 |
Triode
Join Date: Nov 2005
Location: South Manchester, UK.
Posts: 36
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Removing a seized screw.
Apologies if this has been covered may times before, but I have a single seized screw that refuses to come undone.
It is one of the eight that holds the main plastic casing to the metal chassis of a Teac X10 tape machine. Ironically the two obviously rusty ones have already come out. I've tried soaking in penetrating oil overnight, and also doing a bit of a tighten followed by a rapid untighten, but it's staying put. Sadly the slots are now a little mashed as I thought it had started to undo not realising I was just ruining the head :-( |
12th Aug 2012, 12:15 am | #2 |
Retired Dormant Member
Join Date: Jul 2010
Location: Buckingham
Posts: 20
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Re: seized screw
What size is the screw? There are very small but effective small screw removing tools available. They work on an anti clockwise rotation and then bite into the screw head enough for the screw to be removed.
Failing that you should still be able to carefully just drill the head off. Slowly so as not to overheat the plastic. Then remove the cover. There should be a stub of the old screw left behind this can then carefully be drilled out or the stub turned, sometimes better from underneath so you effectively screw it all the way through rather than unscrew it. |
12th Aug 2012, 7:24 am | #3 |
Triode
Join Date: Nov 2005
Location: South Manchester, UK.
Posts: 36
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Re: Removing a seized screw.
Thanks Sunhouse, some helpful suggestions. The screw head is actually about 6mm across, although the design makes it look like its a 4mm screw head with a wider diameter washer beneath.
I'll have a look for screw extractors... |
12th Aug 2012, 10:22 am | #4 |
Octode
Join Date: Aug 2006
Location: Rye, East Sussex, UK.
Posts: 1,647
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Re: Removing a seized screw.
Cross-head screws were designed to assist in assembly, not disassembly - the correct screwdriver is essential but I gather it is too late to be pedantic.
If tightening and penetrating oil has failed, the usual trick of applied heat (soldering iron tip) and impact hammer usually works, but the hammer is obviously not to recommened here, nor the iron on plastic! You'll be very unlikely to find a small enough screw extractor that size - even if there is one it would most likely shear and give you even more problems. Your safest bet is to find a decent, hardened steel file with a fine squared tang (not a cheapo Chinese job). Drill a pilot hole, apply heat from a soldering iron, insert tang and apply a spanner to the file, under weight and pray! I always assemble screws with light smear of grease to stop seizure. Barry PS: Are you sure there is not a retaining nut at the other end? Last edited by brenellic2000; 12th Aug 2012 at 10:25 am. Reason: spelink |
12th Aug 2012, 10:51 am | #5 |
Heptode
Join Date: May 2005
Location: Oxfordshire, UK.
Posts: 852
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Re: Removing a seized screw.
Hi,
I have had reasonable success putting the screwdriver into the slots (albeit worn a little) and giving a slight tap with a Hammer to the screwdriver's end. This can help in loosening it and drives the driver into the screw for a better fit. This technique is obviously no good for something that is sensitive to knocks such as something with a Hard Drive but should be ok on a X-10 (Reel to Reel (?)). If that fails I have also had good success using a sturdy pair of wire cutters if you can get them on to the head. No good if the screw is recessed. Bite into the screw's head and when you think you have got a good grip try to turn the screw. This damages the screw beyond re-use but more often than not it is there by now anyway. Regards, James. |
12th Aug 2012, 11:42 am | #6 |
Retired Dormant Member
Join Date: Jul 2010
Location: Buckingham
Posts: 20
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Re: Removing a seized screw.
This is the sort of thing.
http://www.amazon.co.uk/Trend-GRABSE...ref=pd_sxp_f_r Snap-on have a small set if you see a Snap-On van. I would use a small left hand drill bit first as they often bite enough to remove things on their own. The screw is unimportant now, not damaging anything else is the priority. |
12th Aug 2012, 1:41 pm | #7 |
Octode
Join Date: Aug 2006
Location: Rye, East Sussex, UK.
Posts: 1,647
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Re: Removing a seized screw.
Those head-grab type extractors (as opposed to traditional tap-type extractors) go from No.6 woodscrew (1/8" 3mm shank upwards) so you may be lucky. Axminster Tools do them as well far cheaper than Snap-On! Most are branded Rolston/Irwin etc but these cheapos all come from the same Far Eastern melting pot!
Wire cutters, as James suggest, will do the job but make sure they have flat face and not a bevelled cutting edge, else they'll spring off! Good luck! |
12th Aug 2012, 1:49 pm | #8 |
Nonode
Join Date: Jan 2010
Location: Edinburgh, UK.
Posts: 2,008
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Re: Removing a seized screw.
A good dose of freezer spray might just shrink the screw enough to free it.
Al
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12th Aug 2012, 4:55 pm | #9 |
Retired Dormant Member
Join Date: Jul 2010
Location: Buckingham
Posts: 20
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Re: Removing a seized screw.
Not quite sure why you appear so hostile Brenellic2000.
The Snap-On tool I was referring to is a different item but does remove small screws. It may interest you to know I purchased a set of the basic screw removal tools last year for a fiver from my local Snap-On van. Anyway there is now more than enough advice on this thread. Best of luck. |
12th Aug 2012, 5:44 pm | #10 |
Retired Dormant Member
Join Date: Jan 2007
Location: Lampeter, Dyfed, Wales, UK.
Posts: 369
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Re: Removing a seized screw.
Try heating it with a soldering iron.
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12th Aug 2012, 6:49 pm | #11 |
Retired Dormant Member
Join Date: Nov 2011
Location: Bristol, UK.
Posts: 168
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Re: Removing a seized screw.
I agree with the guy that said that the right screwdriver is vital. Don't use a phillips driver in a pozi screw! It'll usually work ok, but if the screw it tight, the driver will just mash the head.
As an added tip, a single drop of oil on the screwhead makes a huge difference to the grip the driver can get on the screw - you'd think it would slip out easier, but that isn't the case, it really helps you get torque without slipping or mashing the head. How it works, I have no idea - but it does! |
12th Aug 2012, 7:16 pm | #12 |
Triode
Join Date: Nov 2005
Location: South Manchester, UK.
Posts: 36
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Re: Removing a seized screw.
Thanks for all the tips everyone, very helpful. I'll report back...
I'm not sure where the idea I was using the wrong-sized screwdriver came from! But I can reassure you the screwdriver was certainly the correct size - I have a large selection and have been using them for years! The trouble is, all of the other seven screws that hold the case on needed a bit of effort to undo, but whereas the seized threads with the others 'gave' without mishap, the crosshead on this one gave before the threads did. Incidentally, this is an exceptionally neglected Teac X10 that may just be too far gone once I get inside. It looks rather like the tape-recorder equivalent of a barn find in the classic car world! |
12th Aug 2012, 7:34 pm | #13 |
Moderator
Join Date: Dec 2010
Location: Exeter, Devon and Poole, Dorset UK.
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Re: Removing a seized screw.
That tip about using oil from DragonForce is interesting.
I wondering how it might work. Perhaps its a hydraulic effect and the oil effectively transmits the force to the screw head increasing the effective surface area contact between the screw and the driver. Normally the actual contact area between screw and driver would be quite small. That might be nonsense of course but I am just speculating I have no special knowledge in this area. Cheers Mike T
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13th Aug 2012, 12:01 am | #14 |
Rest in Peace
Join Date: Jun 2006
Location: Chard, South Somerset, UK.
Posts: 7,457
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Re: Removing a seized screw.
If you have access to a Dremel and a small, thin grindstone to fit it, you should be able to grind a diametrical slot across the remains of the head and thus use a plain chisel-ended screwdriver to extract that screw.
Al. |
13th Aug 2012, 1:02 am | #15 |
Dekatron
Join Date: Apr 2012
Location: Worksop, Nottinghamshire, UK.
Posts: 5,549
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Re: Removing a seized screw.
Last time iI tried to grind a stuck screw in order to get it out with a flat blade the head split so that i ended up with a stuck screw now having only half a head
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13th Aug 2012, 8:40 am | #16 |
Octode
Join Date: Aug 2006
Location: Rye, East Sussex, UK.
Posts: 1,647
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Re: Removing a seized screw.
Re Cobalt's comments - usually the oil works by increasing surface tension and thus grip - it seems incredible but that' s the theory .. and yes it does work, provided you don't over-oil or grease!
The only screwdrivers and heads guaranteed to fit perfectly are (or were!) proper GKN 'Posidrive' and 'Superdrive' ones - they should have a cross-hair pattern stamped on the head, but these days every Tom Dick and Harry produces posidrives, some better than others. 'Posidrive' screws have flat facetted sides and a double angled profile - the screwdriver will grip and hold a properly made 'Posidrive' screw head and allow increased torque - which neither the Phillips nor bog standard cross headed screws will - the older Phillips has a shallow curved profile and are sloppy fit. Good tools and screws cost money! I wonder how many people have ever checked their flat bladed screwdrivers? 99% will be well tapered an rounded where it fits the screw head - that's why they chew heads! They need to be squared to allow the blade to grip. Sorry Sunhouse, I wasn't being offensive towards Snap-on!!, but 99% of us will never ever see a Snap-on van or driver! And good as Snap-on tools are, they used to be very expensive... but times have changed and it may be possible to buy on-line now without an account. Barry |
13th Aug 2012, 9:17 am | #17 |
Octode
Join Date: Apr 2009
Location: Aylesbury, Buckinghamshire, UK.
Posts: 1,522
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Re: Removing a seized screw.
Along the same lines as the idea of using oil on the tip of the screw driver (which to me defies logic), a dab of grinding (lapping) paste works wonders.
Rob.
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14th Aug 2012, 12:18 am | #18 |
Retired Dormant Member
Join Date: Apr 2003
Location: Salt Spring Island, BC, Canada
Posts: 368
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Re: Removing a seized screw.
Apply a well fitting screwdriver to the screw head and apply a moderate unscrewing torque. At this point try tapping the the end of the screwdriver with a hammer. Remember, moderation at all times.
John. |
14th Aug 2012, 8:08 am | #19 |
Octode
Join Date: Aug 2006
Location: Rye, East Sussex, UK.
Posts: 1,647
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Re: Removing a seized screw.
... and the longer the screwdriver shank, the greater the torque can be applied with the least effort! Fizzicks!!
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14th Aug 2012, 12:38 pm | #20 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,528
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Re: Removing a seized screw.
Fizzicks indeed!
Physics would suggest that the larger the diameter of the screwdriver handle, the greater the torque that can be applied. What a longer driver does is increase the distance the handle's end centre can be away from its ideal place coaxial with the screw before the angle causes the point to cam out of the screwhead under the applied torque.
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