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PostPosted: Fri May 24, 2013 8:22 am 
Retro Guru

Joined: Tue Dec 21, 2010 6:31 pm
Posts: 1112
Hello,

Does anyone have any advice for cleaning the threads out on a campagnolo RD hanger?

I had a frame resprayed but it came back with paint on the threads of the hanger.

It's an early 1970s frame and from what I understand, I need a 10mm x 26tpi tap - but these aren't easy to find. Anyone got an idea where to look?

I read somewhere that it's possible to use a campagnolo rear axle to chase out the thread if you screw it in carefully from the back of the hanger. It doesn't sound like a terribly good idea though.

My local bike shops are pretty clueless when it comes to old bikes, they either can't or don't want to help. I could send it back to the people who sprayed it but that could take weeks.

Cheers for any advice,

Johnny


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PostPosted: Fri May 24, 2013 9:10 am 
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Joined: Wed Apr 25, 2012 2:08 pm
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Location: Shrewsbury
You need an M10 x 1.0 mm tap. All drop outs have the same thread as far as I know.

I have one in the shed of dread I can post if you want to borrow one?


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PostPosted: Fri May 24, 2013 9:42 am 
PoTM Winner
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Joined: Tue Sep 25, 2012 7:21 pm
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One thing I learnt from having a frame repainted is put bolts in or cover the threads.

Clearing paint out of the downtube gear leaver bosses was a right PITA ...


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PostPosted: Fri May 24, 2013 9:53 am 
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Joined: Tue Dec 21, 2010 6:31 pm
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Thanks chaps,

@Robbied: It would be great if I could borrow your tap, if you don't mind posting to Belgium. If PM your details I can pay the postage in advance. Do you want some kind of deposit in case anything goes wrong?

@Montello: Yes, that sounds horrible. Luckily my frame was too old to have braze ons. Presumably you also have to tell them to leave any bolts in so some clever dick doesn't remove them...

Johnny


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PostPosted: Fri May 24, 2013 11:35 am 
rBoTM Winner
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Location: Vienna, Austria
How bad is it? How much damage can be done by er, forcing the bolt through? Or are you worried about the paint around the hole flaking off?


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PostPosted: Fri May 24, 2013 12:00 pm 
Retro Guru

Joined: Tue Dec 21, 2010 6:31 pm
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agentorange wrote:
How bad is it? How much damage can be done by er, forcing the bolt through? Or are you worried about the paint around the hole flaking off?


Problem is I don't know how much damage could be done,
but a stripped hanger thread or derailleur bolt or (as you say) flaked off paint is never going to be fun. The paint is fairly thick too, so I don't know if forcing the bolt through would work. I think I'd prefer to try to do it properly, this time at least :oops:


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PostPosted: Fri May 24, 2013 2:21 pm 
retrobike rider
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Joined: Tue Jan 29, 2008 11:04 pm
Posts: 1802
Location: A wretched hive of scum and villainy...
Even with the tap, you should clean off the paint around the start of the thread. Otherwise it could start a new thread in the paint not follow the original.

I'd lightly run a countersink onto the hole (neatest), or run a knife around the edge of the hole first.

All the best,


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PostPosted: Fri May 24, 2013 4:35 pm 
r.B.o.T.M. & P.o.T.M. Winner
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Location: Camel Land
metric threads in a 70"s Frame - I'm not sure on that so be careful as metric thread angles differ by 5 degs from Imperial. Imperial 55 degs & Metric 60 degs.


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PostPosted: Wed May 29, 2013 9:05 am 
Old School Grand Master

Joined: Tue Oct 09, 2007 1:55 pm
Posts: 8219
Location: New Forest, UK
One other tip: if you have space, try tapping from the inside of the dropouts: if you get it wrong it will not be curtains for the frame. But firstly I would use a needle and sharp knife tip to clear as much of the paint as possible.


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