Allegro Finished

[chickendrumsticks]

Re: Swiss Allegro 1990 - bottom bracket woes!

So having taken it in for thread cleaning & refitting of cups - I get it back with the adjustable cup threads inside the shell damaged! The cup simply won't start in the thread - there's no "bite" if you understand me. On close inspection there's clear damage to the thread. BTW the cup easily fits in the other (drive) side, so cup clearly OK (both RH thread) and fixed cup won't start on non-drive side either.

What the LBS didn't tell me was that he did not have the right tapping tool (Campag 35 x 1 French Thread) and I can't find - so far - any one who has.e.g local bike shops,also Bob Jackson, Brian Rourke. Trying to ask Mercian now, and have left a message for Dave Yates who's away til next week.

Anyone out there likely to have said tapping tool? Or a method of clearing thread without? Clearly the frame is valuless if I can't fix it! HELP please.

Just spoken to Mercian (they don't have the tap either) and they said try a push fit ACOR - or summat. Whadya think? A local LBS said don't because they can come loose etc etc.

 

[KermitGKona88]

Re:

Have a look at this one


http://www.ebay.co.uk/itm/First-threadl ... PdWxMctjdQ

 

[chickendrumsticks]

Re:

Gee thanks Kermy! Yes - looks good but a bit more than I wanted to pay - and a bit colourful for me too. Awaiting contact with Dave Yates, I think, in case he has a tap to clean the damaged thread. But failing that a push fit seems the obvious fix. Why didn't I think of it or (apart from Mercian who were most helpful and suggested it) none of the myriad frame builders, mechanics or LBS's that I spoke to mention it as a solution. I should have known I'd get a sensible answer here

 

[LongLegsRetro]

Re: Swiss Allegro 1990 - bottom bracket woes

If you can't find a tap, Get a super fine mini grinding wheel, something like you would use on a dremel and use it to very gently chase the compromised parts of the thread out by hand, (not using the dremiel) be patient and take it carefully and it will clean up.

As a last resort try one of these;

https://www.veloduo.co.uk/products/velo ... ss-raleigh

Cheaper than scraping the frame.

 

[chickendrumsticks]

Re:

Thanks LLR - a super suggestion. I had thought of using a dremel or summat similar, but was afraid of doing more damage. But you say use it manually? without power? if I understand you correctly?

More than happy to have a go - even if I make matters worse (unlikely I hope as problem is v. obvious near the start of the thread) I can go the other route. i like the look of those bbs you pointed me at, they look great quality, but again maybe a wee bit more than I had bargained for

 

[LongLegsRetro]

Re: Swiss Allegro 1990 - bottom bracket woes

Ah, yeah, I knew what I meant, forget the drenel tool it's self, way to aggressive.

Seeing as you have a French bottom bracket and it's right handed, all you need is a M35x1.0 engineers tap, it's not a special bike only tool, and it is not that hard to come by, but expensive, so you could try asking round local engineering firms as they are likely to have the big stuff and will probably be more than happy to help.

Failing that, I'm coming at this from an engineering angle of how do I get this patched up in the field with out the proper tools. . .

All you want is a super fine grinding/cutting disc, only mentioned dremel to clarify what sort of grinding disc, just use the disc manually with ya digits like a file, as you would if you were trying to clean up the cup thread, it might help to attatch it to the disc holder, depends how deep into the bottom bracket you have to work.

Once you get it cleaned up enough to start the cup winding in, don't be tempted to wind it all the way in, just half a turn or so, then wind it back out, clean up the cup threads, then try again a bit further back out etc. use some light oil on the cup threads too.

Good luck.

 

[torqueless]

Re:

I'm not familiar with dremel-sized cutting discs, which may well be the better option, so take what follows with that in mind:

If you are going to clean out the thread by hand, my preferred (non-specialised) tool would be a sharp point that you are sure is reaching the bottom of the thread without fouling on the sides of the thread. And work from the inside outwards. I've used a sharp sewing needle before. That is more to clean out gunked up threads than to reshape damaged threads though.

If the cup won't start it is possible that the only problem is that the 'doorway' to the thread- its very start- is distorted/blocked. It might help to use the (sharp) point of a needle file in the 'doorway', the file held close to its point and the point held as close to vertical to the thread as access will allow, again working from the inside outwards. You could also use a fine file to gently 'break down' the right angle where the thread meets the outer face of the shell, being careful not to create yet more distortion/blockage.

Proper engineers no doubt have more efficient and effective dedicated hand-tools for jobs like this when a tap is either not available or overkill.. a 'thread-chaser'?

 

[chickendrumsticks]

Re: Swiss Allegro 1990 - bottom bracket woes

Thanks guys - to LLR for clarification, I can just imagine the chaos if I'd been tempted to use a dremel itself!
Torqueless - you must have been looking over my shoulder these last 3 hours (are you my Guardian Angel?) because that's exactly what I tried - a sharp, fine needle pointed file from a set used for fine modelling work. Using it's point I carefully worked away at the thread (luckily it was only the outer one or two needing fettling) until some semblance of a "doorway" (as you so eloquently put it) seemed to form. There was still a bit of powder coating but mainly it was removing steel from between the threads where they had been filed from the look of it...

Then I used the fixed cup because it has flats that I could grip to see if I could get a bite - and it worked! Although very sticky I managed to drive in the cup straight and true with some pressure on top - forwards, a bit backwards, forward again, back again and so on - until it was all the way in. Took it out and the adjustable cup went in too. Reassemble the whole thing and it's as smooth as silk - well maybe coarse linen, but OK.

Thanks again for your interest and input. How reassuring to know there are people here willing and able to share their experience and ideas. Wow!

 

[KermitGKona88]

Re:

What about some of these :?:

https://www.machinemart.co.uk/p/10pce-riffler-file-set/

 

[chickendrumsticks]

Re:

Yes, any of those would've done the trick too thanks. Mine are diamond needle point or something .

But did you see those stainless probes? :shock: I dread to think where or what they might probe...I got a toothache just reading about them.