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PostPosted: Fri May 17, 2019 11:44 am 
r.B.o.T.M. & P.o.T.M. Winner
r.B.o.T.M. & P.o.T.M. Winner
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Joined: Sun Jul 11, 2010 1:41 pm
Posts: 2812
Location: Plymouth, UK
Had the same issue on a frame year before last, I chased the threads through with a old cup bolted to a suitable spanner, turned it half a turn then back, then half a turn more and back, and so forth... Cleaned the thread through in the end. A little squirt of WD helped too.


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PostPosted: Fri May 17, 2019 11:58 am 
Retro Guru
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Joined: Wed Mar 26, 2014 5:58 am
Posts: 537
Location: Wild-wild-wild-EAST
Been there, done that.

Wire brush + liberal doses of brake cleaner sprayed on the threads -> repeat until statisfaction. If the threads are OK anyway, there shouldn't be a big problem with the installation after that.

Blasting media residue + paint patches can be removed with a bit of dedication and care (and a good metal wire brush). I usually remove all paint inside the shell, if necessary and just put lithium grease coat on the naked areas to prevent corrosion.

Apart from these, some OEM dried threadlock fluid on the bottom bracket cups can also cause resistance when turning them into the shell with bare hands. Don't remove this OEM threadlock layer, just make sure the shell threads are nice & clean and you install them correctly.

I've learnt the hard way that bloody BBs must be installed with the utmost care and attention to detail, and this attitude always pays off, especially at places where labourers are decently paid anyway.


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PostPosted: Fri May 17, 2019 12:48 pm 
Old School Grand Master
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Joined: Fri Oct 14, 2011 8:41 pm
Posts: 9702
Location: Cumbria
pigman beat me to it lol


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PostPosted: Fri May 17, 2019 12:51 pm 
Devout Dirtbag

Joined: Fri Aug 24, 2018 9:48 am
Posts: 130
Location: Copenhagen, Denmark
Is there any way to tell if the threads are okay? I mean, it's a steel frame, and the cups used have only been aluminium - could a cross-threaded alu cup damage a steel shell?

Thanks to you and everyone else so far - I've never had this much of a problem in 25 years of building/renovating bikes.

fearfactoryüberalles wrote:
Been there, done that.

Wire brush + liberal doses of brake cleaner sprayed on the threads -> repeat until statisfaction. If the threads are OK anyway, there shouldn't be a big problem with the installation after that.

Blasting media residue + paint patches can be removed with a bit of dedication and care (and a good metal wire brush). I usually remove all paint inside the shell, if necessary and just put lithium grease coat on the naked areas to prevent corrosion.

Apart from these, some OEM dried threadlock fluid on the bottom bracket cups can also cause resistance when turning them into the shell with bare hands. Don't remove this OEM threadlock layer, just make sure the shell threads are nice & clean and you install them correctly.

I've learnt the hard way that bloody BBs must be installed with the utmost care and attention to detail, and this attitude always pays off, especially at places where labourers are decently paid anyway.


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 Post subject: Re:
PostPosted: Fri May 17, 2019 6:07 pm 
Devout Dirtbag

Joined: Fri Aug 24, 2018 9:48 am
Posts: 130
Location: Copenhagen, Denmark
What about a Dremel with a wire (brass) brush?


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 Post subject: Re:
PostPosted: Fri May 17, 2019 6:26 pm 
Gold Trader
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Joined: Mon Jan 15, 2007 11:40 am
Posts: 3809
could a cross-threaded alu cup damage a steel shell?

Very very unlikely, alloy will always get messed up before steel, when they're threaded together.


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 Post subject: Re:
PostPosted: Sun May 19, 2019 4:53 pm 
Devout Dirtbag

Joined: Fri Aug 24, 2018 9:48 am
Posts: 130
Location: Copenhagen, Denmark
So, I have tried with a variety of wire brushes, a Dremel, acetone and a small pick. Still no more movement than before.

I don't have any old Italian steel bottom brackets so can't make a tool to chase the threads myself, so it looks like I will have to bankrupt myself, going to a Danish bike shop. :cry:


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 Post subject: Re:
PostPosted: Sun May 26, 2019 3:04 pm 
Dirt Disciple

Joined: Fri Aug 04, 2017 10:43 pm
Posts: 76
Not sure how old your frame is, but when I was restoring my dad's old steel bike, the threads were not cut deeply enough into the bottom bracket to get a modern BB (cartridge square taper type) 'all the way in'. I had to find an old cup cone and axle on Ebay, but they weren't very expensive, and just use new bearings. But maybe your bike is newer as you're looking to install an octolink.


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