Warped BB?

[kloeshuman]

Not sure if anyone will know for sure, but I had started to do a SS build on a old frame I had. The BB cup broke when I was taking off the old crank set, I used that crank on my road build. So the other day I went back to removing the old bb. I ended up having to put a small amount of heat to it in order to break it free. Now, I can not get a bb to go back in straight, I tried the old one which was fine other then needing a new cup, I tried a new one also, still the same. It will not go in straight, not off by much, but enough that the other cup will not go on without binding on the spindle. Do you think that what heat I did use messed up that area around the bb? I should have said it is a aluminum frame. Should I scrap the frame and start another project? Not really a ss frame but I bike I put a lot of miles on so I was kinda hoping to keep her going.

 

[Globalti]

Unlikely. More likely you've crossed the threads on the cup and it's gone in crooked.

Take it all down to a bike shop who will have a proper tool for reaming out the thread in the BB.

 

[kloeshuman]

I thought that might be the case but it seems as though it would thread hard if it was cross threaded?? I have tried over and over but still the same. I will talk to my LBS and see if they think the same.
Thanks

 

[Globalti]

Think about all the heat that's used in building a traditional frame - sometimes the lugs are heated red hot before the brazing is done. Okay it's always done evenly but I've never heard of heat distorting a frame. I would be more concerned about altering the temper of the metal by cooling it too fast.

If you had to butcher a cup to get it out and it's the same side that's giving you problems, my money is on a damaged thread, especially in a soft alloy frame.

For future reference Sheldon Brown's website suggests a good method of removing stuck BB cups by fitting a nut and bolt into them and turning the bolt head.

 

[RecordAceFromNew]

The strength and fatigue life of aluminium alloy (e.g. 7005) is not improved by heat, but of course the effect is dependent on temperature and exposure duration which we know nothing about.

If the structural integrity of the bb shell has not been overly compromised then a possible solution to deal with the alignment problem is to use a threadless bb such as this. Cheaper ones are available from e.g. ebay.

 

[kloeshuman]

You were right, threads were bugged up. They ran a tap through it and its fine now. In fact.....I was able to finish the ss build today. I still need to pick up the proper chain but I'm in business. Thanks for the advice, for some reason it had never crossed my mind.

 

[kloeshuman]

 

[Globalti]

Nice! Couldn't you find a matching front wheel though?

 

[kloeshuman]

no, this is what I have to work with for now.