Sheared bolt

Inland paddling
eeonz
Posts: 849
Joined: Sun Feb 15, 2009 3:12 pm
Contact:

Sheared bolt

Post by eeonz » Tue Jan 04, 2011 10:55 am

When working on my boat last night, one of the bolts in my mambas foot block sheared off, leaving some of the bolt within the aluminium strut. Annoyingly, it didn't leave enough of the bolt standing proud to get any real purchase with a pair of pliers. I tried cutting a slot across the top to get a flathead screw driver in. but it seems to be made of stronger stuff than my hacksaw blade...

Anyway:

Image

Uploaded with ImageShack.us

Any ideas for getting it out please? I'd like to be able to do it without having to drill and re-tap the hole, or having to invest too much money in to specialist tools. That said, my tool box is pretty limited...

cheers
Ian
http://www.iboutdoor.com- Your outdoor resource!

User avatar
RichA
Posts: 2836
Joined: Mon Jan 17, 2005 12:51 am

Re: Sheared bolt

Post by RichA » Tue Jan 04, 2011 11:00 am

This would have it out in seconds:

http://www.screwfix.com/prods/20084/Van ... r-Set-8-Pc


Otherwise can you borrow a proper set of mole grips or stilsons?



If you don't want to spend anything then soak it in WD40 or Plusgas overnight and try again. There will probably be corrosion between the aluminium and the stainless steel bolt which needs breaking. Heat would help. Leave it over a boiling pan of water for 20 min and try again while it's still hot?

Bod
Posts: 1591
Joined: Fri Sep 17, 2004 1:50 pm
Location: Exeter

Re: Sheared bolt

Post by Bod » Tue Jan 04, 2011 12:01 pm

If molegrips don't get it, then file a flat top and bottom across the most prominent bit of the bolt until an open-ended spanner fits.
John B.

User avatar
Kayak-Bloke
Posts: 1445
Joined: Wed Mar 07, 2007 12:56 pm
Location: (Ever Wet) South Wales

Re: Sheared bolt

Post by Kayak-Bloke » Tue Jan 04, 2011 12:15 pm

If you still can't do it. Ask around your mates and see if anyone has a set of "easyouts" any half decent amateur mechanic will have a set.


Firstly spray lubricant onto the bolt body and let it seep into the threads. Hlafords etc sell specialists fluids for this type of job but WD40 will do if you want to keep it simple.
Drill a hole into the top of the bolt and insert the 'easyout' due to the thread direction on the tool as it tightens itself into the bolt body it will start to undo the bolt.

I've used 'Easyouts' to remove sheared cylinder head bolts they are good bits of kit.

Good luck!

User avatar
scottdog007
Posts: 1317
Joined: Fri Apr 03, 2009 10:34 pm
Location: Hertfordshire.
Been thanked: 1 time

Re: Sheared bolt

Post by scottdog007 » Tue Jan 04, 2011 1:32 pm

The hardness you are finding while trying to cut it with a saw is probably due to being chrome plated. Chrome is hard. It might be that you will need to grind it out using a dremel or at least grind the hard stuff off so you can drill it out. Then either re-tap or use a bolt with a locking nut.

So frustrating.

GrumpyPumpy
Posts: 153
Joined: Tue Sep 14, 2010 7:15 pm

Re: Sheared bolt

Post by GrumpyPumpy » Tue Jan 04, 2011 2:18 pm

Be careful if you drill and or use Easyouts if you break them off they are impossible to drill because of the hardness of them.

If you can heat it without damaging anything else (remember aluminium has a low melting point) try heating it to expand the metal surrounding the broken bolt and tap the broken bolt round with a centre punch, Mark the centre with the punch first in case you have to drill it out.

Drill it slightly smaller than the bolt say for a 6mm bolt 4.5mm and collapse the remaining piece of bolt inwards.

GP

Mikers
Posts: 187
Joined: Tue Nov 30, 2010 3:00 pm

Re: Sheared bolt

Post by Mikers » Tue Jan 04, 2011 2:33 pm

What size is the bolt?

Soak in WD40, plusgas or similar overnight.

If the bolt is large enough, drill a small hole in the centre.
Remove the handle from a small file (needle file if necessary).
Insert the handle end of the file into the drilled hole. Tap gently into position.
Turn file with a spanner, eh vol-wah. The bolt will come loose.

Much easier to drill and retap, or drill out completely, climb inside the boat and use a nut.

User avatar
shanclan
Posts: 1026
Joined: Sat Jul 19, 2008 12:57 pm
Location: Monmouth
Been thanked: 1 time
Contact:

Re: Sheared bolt

Post by shanclan » Tue Jan 04, 2011 3:58 pm

It does sound like it has cold welded a bit. (stainless plus aluminium plus water plus electrochemistry)

Heat is good as the two metals will expand at different rates, Use a blow torch if you have one. Plusgas etc also as suggested.

The other thing you could do is use a vice as it looks the bolt is long enough to be held (tightly). You can then turn the aluminium strut and will have loads of leverage.

User avatar
Jim
Posts: 13871
Joined: Sun Apr 21, 2002 2:14 pm
Location: Dumbarton
Has thanked: 7 times
Been thanked: 37 times

Re: Sheared bolt

Post by Jim » Tue Jan 04, 2011 4:11 pm

scottdog007 wrote:The hardness you are finding while trying to cut it with a saw is probably due to being chrome plated. Chrome is hard. It might be that you will need to grind it out using a dremel or at least grind the hard stuff off so you can drill it out. Then either re-tap or use a bolt with a locking nut.

So frustrating.
Hmm, Chrome might be part of it but I doubt if it's chrome plated! More limely a chrome alloy AKA stainless steel!
If it's a decent marine grade 316 stainless it may be difficult to saw or drill and you may already have made more trouble for yourself - if you get these alloys hot they can harden up and become even harder to cut, but they normally turn slightly blue on the way.

If it hasn't turned blue then you may still be in luck but throw your hacksaw blade away and go to a proper tool shop and buy some quality hacksaw blades, you may even get some designed for stainless but if not just go with good quality ones.
Make sure you apply plenty of oil as you cut to keep it cool and make it cut better - I use CT90 cutting fluid and hacksaw 304 grade stainless all the time, I do avoid 316 though.

If sawing won't work and you need to drill it, either for an easi-out or to collapse it in on itself, use a centre punch as already mentioned to prevent the drill slipping, use a brand new HSS drill with oil at a low speed, or better still use a cobalt drill (cobalt drills are always recommended for use with easi-outs).

Other things to try are dousing in penetrating oil and hitting sharply with a hammer - this won't undo it but may break any build up of oxidisation (corrosion, think of it as aluminium rust) which will make it easier to undo, as soon as a tiny crack opens up the penetrating oil should run in and help lubricate it.

If you are going to try heating, I would recommend doing it very gently with aluminum involved. If you want to anneal aluminium a good indicator is to wipe soap or washing up liquid on it, and then heat until the soap starts to burn - at this point the aluminium will be soft and easy to bend and shape - you don't want it to get to this stage so you could use soap as an indicator, if it starts to burn you have gone too far, unfortunately it happens quite suddenly so it's not a great indicator if you want to avoid annealing the bar.

If all else fails and the screw has hardened up so you can't drill or saw it, you could try a dremel with a mini grinding wheel on - note that this will generate a lot of heat (but not be bothered by the hardness of the stainless) so be careful not to overheat the aluminium by conduction. Also don't touch it as soom as you stop the dremel, it will burn your finger.

If you have to drill it out oversize wrecking the threads, you may be able to use a helicoil to repair it, seems like overkill though. Might be easier just to get a bit of aluminium flat bar and rivet (or bolt) over the oversize hole that you can drill and tap to the original size again, or just through bolt it and put a nut and washer on.

Have fun choosing from all the suggestions!

Paul L
Posts: 407
Joined: Tue Sep 04, 2007 8:57 pm
Location: Middlesbrough

Re: Sheared bolt

Post by Paul L » Tue Jan 04, 2011 4:42 pm

Grip it in a Vice and turn.

Cheers

Paul

User avatar
shanclan
Posts: 1026
Joined: Sat Jul 19, 2008 12:57 pm
Location: Monmouth
Been thanked: 1 time
Contact:

Re: Sheared bolt

Post by shanclan » Tue Jan 04, 2011 5:01 pm

Image Image

Universal toolkit.

User avatar
MikeB
Posts: 8061
Joined: Tue Apr 29, 2003 9:44 pm
Location: Scotland
Has thanked: 9 times
Been thanked: 14 times

Re: Sheared bolt

Post by MikeB » Tue Jan 04, 2011 5:05 pm

eeonz wrote: That said, my tool box is pretty limited...
Visit your local friendly garage ?

Dave Manby
Posts: 2013
Joined: Mon Dec 22, 2003 10:36 am
Location: Llangollen
Been thanked: 10 times
Contact:

Re: Sheared bolt

Post by Dave Manby » Tue Jan 04, 2011 7:51 pm

Soak it in coke also works

minty
Posts: 243
Joined: Thu Dec 29, 2005 4:00 pm
Location: Scotland, Blairgowrie

Re: Sheared bolt

Post by minty » Tue Jan 04, 2011 8:55 pm

Before you go to the bother of drilling and easy outs be aware that some easy outs expand into the drilled section and could distort the stud and aluminium. I would go to your local garage where they should have welding equipment. Get them to put a plain steel repair washer over the stud and then a nut over the thread. A spot weld on the nut to the thread and you should be able to use a spanner to unscrew the section. The washer should protect the aluminium bar from spatter and melting. I have used this method on sheared and seized studs even where they are flush with the surrounding metal (If thats the case then you weld the washer to the broken section and then the weld the nut to the washer)
alick
Ambition and ability I've got too much of one and very little of the other

GrumpyPumpy
Posts: 153
Joined: Tue Sep 14, 2010 7:15 pm

Re: Sheared bolt

Post by GrumpyPumpy » Tue Jan 04, 2011 10:08 pm

shanclan wrote:Image

Universal toolkit.
A two pound air cooled flattening spanner!

Couldn't get the pics at work didn't see the bit sticking out, smack it a couple times to shake it up a bit to break the corrosion, a bit of heat and hold the bit sticking out in a vice and turn gently back and forth until it free's up.

Let it cool down apply some freeing oil and unscrew.

Agent Nomad
Posts: 256
Joined: Sat Oct 28, 2006 10:14 pm

Re: Sheared bolt

Post by Agent Nomad » Tue Jan 04, 2011 11:22 pm

Most of you are makingthis harder than it needs to be

There is a bit stuck out both sides put the longest part in a good engineers vice do up tight [if the other part of thread is damaged cut it off flush] now start to turn the alloy bar a little each way add wd40 and work it loose and then turn it out

Before replacing with a new bolt run a correct size tap through the hole some Dagger boats are metric some are UNC threads

eeonz
Posts: 849
Joined: Sun Feb 15, 2009 3:12 pm
Contact:

Re: Sheared bolt

Post by eeonz » Tue Jan 04, 2011 11:29 pm

Thanks for all the replies! I had a another crack at it today, with a friends hacksaw. I gave it the WD40 treatment, then i managed to cut a slot in it, but the bolt really is tiny, so turning the screw driver just mashed it up. That's when i decided it was best to give up before doing more damage!

Previously with a similar problem, I took an item to an engineer in town who welded/brazed(?) a small rod on to a stripped screw then turned that with pliers. That did have a bigger head on it to work with though. Still I'll call in and see if he can work his magic again.

I like the idea of using a vice, but there really is only a little bit of bolt sticking out. Attacking it with mole grips didnt work as there wasn't really enough to grab.

Once this is sorted I have another problem to attend to:

Image

Uploaded with ImageShack.us

The two bolts on the other side are still wedged firmly in place. Again, I think my efforts will do more harm than good, so i'll hand it over to a professional!

Thanks all :)

Before replacing with a new bolt run a correct size tap through the hole some Dagger boats are metric some are UNC threads
Probably a daft question, but any idea how to work this out please? Normally i'd try both and see which one fits - but i'd have thought that runs the risk of ruining the threaded hole if I put the wrong one in? I phoned dagger recently, who explained that mambas (or at least some of them) were made in the US, so i'd guess that it would be UNC.
http://www.iboutdoor.com- Your outdoor resource!

User avatar
gonzo
Posts: 438
Joined: Sun Dec 23, 2007 10:44 pm

Re: Sheared bolt

Post by gonzo » Tue Jan 04, 2011 11:38 pm

Ian,

If you can get it over to me at work I'll sort it out for you!

Steve

User avatar
Jim
Posts: 13871
Joined: Sun Apr 21, 2002 2:14 pm
Location: Dumbarton
Has thanked: 7 times
Been thanked: 37 times

Re: Sheared bolt

Post by Jim » Wed Jan 05, 2011 12:52 am

eeonz wrote:
Before replacing with a new bolt run a correct size tap through the hole some Dagger boats are metric some are UNC threads
Probably a daft question, but any idea how to work this out please? Normally I'd try both and see which one fits - but I'd have thought that runs the risk of ruining the threaded hole if I put the wrong one in? I phoned dagger recently, who explained that mambas (or at least some of them) were made in the US, so I'd guess that it would be UNC.
Easy, you got one bolt out OK, you will obviously have UNC and metric thread gauges in your toolbox, just offer each up against the thread and see which fits most closely. If you end up unable to decide, there are a few pitches where the difference is so small that it needs about 20 threads of engagement to jam, I'll bet you have a max of 3 threads in the bar, in which case it won't matter at all which you use. I have American machines, my thread gauges (between about 6 and 10 quid for a set) have been some of my most used tools! Obviously if you have a calliper or micrometer to measure the major diameter it can help decide what the thread is - the digital calliper is also well used!

As for the others, get tapping and dousing in penetrating oil. Shocking to break corrosion conglomeration and a good long soak with penetrating oil is generally the most effective combination. WD40 is OK, penetrating oil is better. Seriously if you take it easy, a bit of hammering and soak overnight for a few days most stuck things unstick. Most people don't have the patience.

GrumpyPumpy
Posts: 153
Joined: Tue Sep 14, 2010 7:15 pm

Re: Sheared bolt

Post by GrumpyPumpy » Wed Jan 05, 2011 5:42 pm

eeonz wrote:Probably a daft question, but any idea how to work this out please? Normally I'd try both and see which one fits - but I'd have thought that runs the risk of ruining the threaded hole if I put the wrong one in? I phoned dagger recently, who explained that mambas (or at least some of them) were made in the US, so I'd guess that it would be UNC.
If you have something like Eurofasteners nearby who supply nut screws washers and bolts (there's a joke in there somewhere) you can try metric or UNC (Unified National Coarse) nuts or more likely with the size of the screws UNF (Unified National Fine) to see if you get a nice fit, not too tight nor too loose, on a clean screw thread then purchase the corresponding correct length screws.
Buy a small tube of Copperslip too, to put on the threads and prevent them siezing again, most car spares dealers stock this it's an anti sieze high temperature grease, beware only use a tiny bit on the actual threads it gets everywhere otherwise and doesn't wash out easily, if at all. It's used on vehicle brake pad metal parts to prevent siezing, I use it on my motorcycle brakes and any screws or bolts I remove or replace, you get the same effect on a bike stainless screws into aluminium frame parts, I've had to drill out and centre punch screws from my Ducati and other bikes same problem wet, muck and steel and aluminium combine to frustrate.

Agent Nomad
Posts: 256
Joined: Sat Oct 28, 2006 10:14 pm

Re: Sheared bolt

Post by Agent Nomad » Wed Jan 05, 2011 7:49 pm

Buy a small tube of Copperslip too, to put on the threads and prevent them siezing again, most car spares dealers stock this it's an anti sieze high temperature grease, beware only use a tiny bit on the actual threads it gets everywhere otherwise and doesn't wash out easily, if at all. It's used on vehicle brake pad metal parts to prevent siezing, I use it on my motorcycle brakes and any screws or bolts I remove or replace, you get the same effect on a bike stainless screws into aluminium frame parts, I've had to drill out and centre punch screws from my Ducati and other bikes same problem wet, muck and steel and aluminium combine to frustrate.
Copper slip is not the friend you think it is Aluminiun, copper, stainless steel add salty water off the road this time of year and you have a mix for corrosion.

GrumpyPumpy
Posts: 153
Joined: Tue Sep 14, 2010 7:15 pm

Re: Sheared bolt

Post by GrumpyPumpy » Wed Jan 05, 2011 8:41 pm

Copper slip is not the friend you think it is Aluminiun, copper, stainless steel add salty water off the road this time of year and you have a mix for corrosion.
Well I have to say I have used it since only being mildly irritated (e.g. not Grumpy yet) as both a truck, car and motorcycle mechanic (40 years) and it's always been my friend, it does what is say's on the tin, tube or whatever.

FYI I don't need thread gauges etc, I grew up in the period of transition between Unified and Metric threads particularly in my years in the USA (early 80's), the USA resisted the Metric system they tried to stick their heads in the sand, in the early 70's Ford UK fitted a mixture of Unified and Metric threaded fittings on the same vehicle, you had to learn the difference or spend a lot of time replacing brake pipes because you had ruined the connecting nuts to wheel cylinders.
By about the mid 70's they went fully Metric.

If I can remember correctly UNF Ford Transit wheel cylinders had blue plugs fitted and metric had red.
I can still remember the valve clearances of a V4 Ford Transit is that sad or what?

User avatar
Jim
Posts: 13871
Joined: Sun Apr 21, 2002 2:14 pm
Location: Dumbarton
Has thanked: 7 times
Been thanked: 37 times

Re: Sheared bolt

Post by Jim » Thu Jan 06, 2011 10:39 am

You would think adding copper to the mix would be a problem wouldn't you? Pretty much every one in buggy racing and most in recreational kite buggying uses a dab of copperslip grease on our stainless bolts to stop the nuts galling or pressure welding on, and I can't remember ever seeing any corrosion as a result of it - we splash salt water and sand all over our bolts! Mind you, most of our buggy parts are also stainless steel. Copper and aluminium dislike each other intensly, so for that maybe you should look for aluslip grease (my mate tracked some down eventually, might have been Frosts, or PR oils) or if thats too much trouble just try to get a dab of some kind of grease on there if you envisage having to undo them again in the future.

Grumpy - when buying modern fastners the Metric and Unified look exactly the same and I'm sure I couldn't tell them apart without measuring! I know what you mean though, I helped a mate disassemble and old landrover for refurbishing, and after a while you get to recognise the different styles of bolts that were used. I'm pretty sure we found BSW as well Unified! Now BSW/BSF you should be able to tell apart - not that telling the 55 degree flank apart from the 60 deg of the others is possible by eye, but because the tips of the threads should be rounded not flat.

User avatar
Ricks-Freestyle-Mind
Posts: 3976
Joined: Mon Dec 20, 2004 8:54 pm
Location: Bury/Preston

Re: Sheared bolt

Post by Ricks-Freestyle-Mind » Thu Jan 06, 2011 10:41 am

I wonder how many paddlers it would take to change a light bulb?

User avatar
MikeB
Posts: 8061
Joined: Tue Apr 29, 2003 9:44 pm
Location: Scotland
Has thanked: 9 times
Been thanked: 14 times

Re: Sheared bolt

Post by MikeB » Thu Jan 06, 2011 12:08 pm

Waxoyle is a surprisngly effective substitute for Coppaslip (which I too rate highly) and ordinary grease. Like Jim, I don't quite know why the copper in Coppaslip doesn't produce a reaction, but it seems not to. Having had an alloy wheel attach itself to a steel hub on a car, and having had to use a lot of effort to release it, it was then smeared with C/slip and the problem was solved for the 3 years I had that vehicle.

User avatar
MikeB
Posts: 8061
Joined: Tue Apr 29, 2003 9:44 pm
Location: Scotland
Has thanked: 9 times
Been thanked: 14 times

Re: Sheared bolt

Post by MikeB » Thu Jan 06, 2011 12:21 pm

Ricks-Freestyle-Mind wrote:I wonder how many paddlers it would take to change a light bulb?
Oh, many.

Would that be a bayonet fitting, screw in, clip in, plug in, large, small, 12 v, 240 v, reflector, clear, frosted, halogen, neon, HID, energy saving or incandesent ???????

Then there's the H&S implications - working at height etc - not to mention all the electrical competence stuff. And of course the packaging and the old bulb will have to be disposed of.

SO many opportunities for input - dealing with sheared bolts is much easier. Mike.

User avatar
davebrads
Posts: 1810
Joined: Sun Feb 24, 2002 11:42 pm
Has thanked: 2 times
Been thanked: 4 times

Re: Sheared bolt

Post by davebrads » Thu Jan 06, 2011 12:29 pm

I've used Loctite on the threaded parts on bicycles. It stops them coming loose when you don't want them to, but prevents them from seizing up when you come to undo them.

User avatar
ol
Posts: 2264
Joined: Sun Feb 29, 2004 6:13 pm
Location: In the middle

Re: Sheared bolt

Post by ol » Thu Jan 06, 2011 3:01 pm

Just to throw another shrimp on the barbie, the footrest assembly is made of very simple flat aluminium bar, if you cant sort it, or strip it out badly, go to a metal merchants and get a bit of matching bar, drill some holes in it, get it tapped, bend it round a corner, jobs a goodun.

User avatar
Jim
Posts: 13871
Joined: Sun Apr 21, 2002 2:14 pm
Location: Dumbarton
Has thanked: 7 times
Been thanked: 37 times

Re: Sheared bolt

Post by Jim » Thu Jan 06, 2011 8:13 pm

ol wrote:Just to throw another shrimp on the barbie, the footrest assembly is made of very simple flat aluminium bar, if you cant sort it, or strip it out badly, go to a metal merchants and get a bit of matching bar....
OK then smartass - what grade of aluminium is it? What series even? :-)

(I already mentioned how to anneal it to put the bend in without breaking it :-) )

eeonz
Posts: 849
Joined: Sun Feb 15, 2009 3:12 pm
Contact:

Re: Sheared bolt

Post by eeonz » Thu Jan 06, 2011 10:25 pm

All better now, but I won't say how much I paid. Sorry Steve, I spotted your very generous offer too late there!

The screws were corroded/oxidised/smegged and possibly loctited as well. The engineer drilled the screw out and tidied it up for me. As for getting the other bolts out, he used a longer allen key than the one I had and manned up to it.

Now to foam it out! Its on the furthest setting already, so I doubt I'll be able to fit much in at all though unfortunately.
http://www.iboutdoor.com- Your outdoor resource!

Post Reply

Return to “Whitewater and Touring”