Thread repair. Did a wrong 'un

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ukdodger
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Thread repair. Did a wrong 'un

Post by ukdodger »

Stupidly I attempted the removal of a chainwheel with a chainwheel remover but without removing the bolt first :( . I know I know.. Result was a stripped thread on the chainwheel. Can this be repaired in any way? I got the chainwheel off using a car wheel hub puller but dont want to put it back unless I can get it off again without the car wheel puller. The chainwheel is this one made of a hard alloy:

http://www.freemanscycles.co.uk/media/c ... _fcs71.jpg

Sob..
fastpedaller
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Re: Thread repair. Did a wrong 'un

Post by fastpedaller »

I don't think even a helicoil would withstand the pull exerted by the crank puller tool. Cost of the helicoil would probably make it uneconomical?
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Mick F
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Re: Thread repair. Did a wrong 'un

Post by Mick F »

I had a bike many years ago and it was the first bike I'd owned with an alu square taper crankset. Prior to that I'd been on the cotter pin system.

One day, I wanted to take my cranks off. I had no extractor, in fact I'd never heard of extractors! :oops:
I used a thick screwdriver as a wedge to push off the cranks. It worked fine, but I did have steel BB cups to allow the screwdriver not to damage anything.

Basically, it's not the end of the world for you. Yes, the Rolls Royce system is to renew the crank, but if you could get hold of suitable wedges and some sort of protection - brass or copper? - you should be ok. After all, how often do you take your cranks off? Mine come off maybe only once or twice a year.
Mick F. Cornwall
fastpedaller
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Re: Thread repair. Did a wrong 'un

Post by fastpedaller »

:idea: Following on from the last suggestion......... if you have one of the car track rod end tools of the design that fits on the steering arm, and has a bolt which tightens to push the track rod end and break the taper's seal, you may be able to use that (with some protective shim, and wind the bolt on to the end of the bb axle to release the crank.
ukdodger
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Re: Thread repair. Did a wrong 'un

Post by ukdodger »

Thanks for all the replies and tips chaps. I thought I was on a loser. What I'll do is buy another chainwheel and chalk it up to experience. My BB is an expensive one so I'm not going to chance the wedges though no doubt it would work.

You'll never know how mad I was when I realised what I'd done. :evil: :evil: :evil:
Brucey
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Re: Thread repair. Did a wrong 'un

Post by Brucey »

if the automotive puller worked once then I'm sure it will work again, so I'd just fit the old crank myself. This would be a much easier decision if the BB were not a posh one though; if it were (say) a BB-UNxx then I'd be thinking that the next time I'd need to take the cranks off, it'd be because the BB unit was headed for the bin.

BTW you may be able to have the cranks machined to accept a larger extractor thread, eg a TA one or something.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
ukdodger
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Re: Thread repair. Did a wrong 'un

Post by ukdodger »

Brucey wrote:if the automotive puller worked once then I'm sure it will work again, so I'd just fit the old crank myself. This would be a much easier decision if the BB were not a posh one though; if it were (say) a BB-UNxx then I'd be thinking that the next time I'd need to take the cranks off, it'd be because the BB unit was headed for the bin.

BTW you may be able to have the cranks machined to accept a larger extractor thread, eg a TA one or something.

cheers


Thanks Brucey. I take the cranks off 3 - 5 a year for cleaning. It's easier than leaving them on so the puller is quick and easy. The auto puller works but it's fiddly and the bike has to laid on it's side. Having them machined I'm guessing would cost more than a new set of cranks.

Cheers
Brucey
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Re: Thread repair. Did a wrong 'un

Post by Brucey »

I'd also suggest a different cleaning regime then!

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
rjb
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Re: Thread repair. Did a wrong 'un

Post by rjb »

If you put the damaged crank back on then when you next come to remove it just unscrew the crank bolt and carry on riding it until it comes loose of its own accord. (you may need to carry a bolt and spanner or allen key to nip it up if it catches you far from home) :wink:
At the last count:- Peugeot 531 pro, Dawes Discovery Tandem, Dawes Kingpin X3, Raleigh 20 stowaway, 1965 Moulton deluxe, Falcon K2 MTB dropped bar tourer, Rudge Bi frame folder, Longstaff trike conversion on a Giant XTC 840 :D
ukdodger
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Re: Thread repair. Did a wrong 'un

Post by ukdodger »

rjb wrote:If you put the damaged crank back on then when you next come to remove it just unscrew the crank bolt and carry on riding it until it comes loose of its own accord. (you may need to carry a bolt and spanner or allen key to nip it up if it catches you far from home) :wink:



Nice idea :D
fastpedaller
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Re: Thread repair. Did a wrong 'un

Post by fastpedaller »

ukdodger wrote:
rjb wrote:If you put the damaged crank back on then when you next come to remove it just unscrew the crank bolt and carry on riding it until it comes loose of its own accord. (you may need to carry a bolt and spanner or allen key to nip it up if it catches you far from home) :wink:



Nice idea :D

I'm not sure I'd advocate that method, because just a few 'wobbles' of the crank could cause too much damage to the taper.
ukdodger
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Re: Thread repair. Did a wrong 'un

Post by ukdodger »

fastpedaller wrote:
ukdodger wrote:
rjb wrote:If you put the damaged crank back on then when you next come to remove it just unscrew the crank bolt and carry on riding it until it comes loose of its own accord. (you may need to carry a bolt and spanner or allen key to nip it up if it catches you far from home) :wink:



Nice idea :D

I'm not sure I'd advocate that method, because just a few 'wobbles' of the crank could cause too much damage to the taper.


That's true but it's an idea if you just cycle up and down the road with the sole purpose of freeing it. It's better than hammering away first one side then the other on the crank. The only thing worse is getting cotter pins out!
pete75
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Re: Thread repair. Did a wrong 'un

Post by pete75 »

Yes it is repairable. You just need a crank repair kit which is a snip at £159.99 .

http://www.winstanleysbikes.co.uk/produ ... oCgEbw_wcB
'Give me my bike, a bit of sunshine - and a stop-off for a lunchtime pint - and I'm a happy man.' - Reg Baker
ukdodger
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Re: Thread repair. Did a wrong 'un

Post by ukdodger »

pete75 wrote:Yes it is repairable. You just need a crank repair kit which is a snip at £159.99 .

http://www.winstanleysbikes.co.uk/produ ... oCgEbw_wcB


Thanks I'll give it a miss!!
jrclimber
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Re: Thread repair. Did a wrong 'un

Post by jrclimber »

I did the same thing. Took the bolt out but forgot the washer. Tried every way to get the crank off without success (though I don't have a hub puller). Eventually took a hacksaw to the crankarm and unbolted the chainrings which I'll be putting on a new crankarm (£20 from Spa)
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