Ream and sleeve?

[piedwagtail91]

a local shop that did frame repairs suggested a cut across the underside of the bottom bracket, this was then tapped together and the gap closed and welded then the threads were recut.he used it a few times and the only paint damage was the weld under the bb which with some touch up paint was ok as no one ever sees that part of the bike.

 

[beanzontoast]

Pied - that's what I would hope as a best-case outcome. I have some really good touch-up paint I've used to cover the odd stone chip, so if that's how it turns out, I'll be well pleased! Will let everyone know how this evolves in case there are others with a similar problem.

 

[mickle]

There are two common methods used, the old school way is to run a few beads of brass into which new threads are cut. This does cause paint damage though. The other method is to bore out the old threads and bond in a sleeve which has new threads cut in it. Not a helicoil as such.

 

[beanzontoast]

There are two common methods used, the old school way is to run a few beads of brass into which new threads are cut. This does cause paint damage though. The other method is to bore out the old threads and bond in a sleeve which has new threads cut in it. Not a helicoil as such.

I won't know for sure until tomorrow, but I'm assuming this is the 'ream and sleeve' approach that Argos Cycles seem to use.

 

[mickle]

I won't know for sure until tomorrow, but I'm assuming this is the 'ream and sleeve' approach that Argos Cycles seem to use.

Yup, no need for a new shell or new paint either.

 

[beanzontoast]

Update...

None of the LBS can help (I thought as much, but worth a shout). Mercian do repairs, but they said they would braze on a whole new shell which then needs a respray, and I was hoping to avoid this.

Argos Cycles have replied that they do the 'ream and sleeve' and have been pretty helpful with advice about getting the bike ready to courier. So looks like that will be the choice.

Hoping it turns out ok!

 

[beanzontoast]

Update 2...

Ok, the frame is back from Argos with the sleeve inserted. However, looking at the bb shell, I notice that on one side, the remaining 'shell' on the frame is an even thickness of metal all the way round the circumference with the sleeve centrally inserted, while on the other side of the frame, there's a lot more thickness to the metal at the bottom of the bb shell than at the top.

I'd expected the reaming to go exactly through the middle of the bb shell, leaving an even thickness of metal all round the rim of the bb on both sides of the frame, and this suggests that it hasn't. What concerns me is, if the reaming isn't straight and the new sleeve isn't in straight, then the bb won't go in straight and the cranks/chain will be tilted when installed. Also, surely if the remaining metal at the top of the bb is substantially thinner than at the bottom, there's going to be a weakness there?

Needless to say I've left word for Argos to contact me to discuss it before I start rebuilding...

Watch this space.

 

[beanzontoast]

Update...

Have spoken with them now and apparently this less-than-perfect alignment is caused by minor variations in the density of the original steel bb casting as the borer goes through to create the tunnel for the new sleeve. They say they've done loads of them and it isn't unusual for this to happen. The sleeve alignment will be ok. They've never had a problem with the resulting sleeve fitting because of the borer issue.

So, I'm happy to say I'm reassured. Looking forward to rebuilding the bike this weekend and having a bit of a reliability ride to see how she feels.