Cannot install bottom bracket (cleaning?)

[FiveAlpha]

So, my frame has arrived back from Bob Jackson, after a respray. I go to install the bottom bracket cups and they will not screw in. They go a third to half way in, by hand, but not smoothly, and then they stop.

I am loathe to force them (Shimano Octalink cups are soft alu) and so I thought it might be dirt in the threads? Any ideas how to clean them (I’ve used degreased and am old toothbrush - didn’t help).

Any ideas, aside from getting the threads chased, which here in Denmark, will literally cost £60?

Thanks

 

[mattr]

If it's only paint, or bead blasting residue, a scalpel or sharp pick run through the threads will do the trick.
Maybe wipe a bit of acetone over the threads to soften the paint up a bit.

 

[FiveAlpha]

Re:

Thanks - there isn’t any paint in there, that I can see (Bob Jackson are super professional), but I will try the pick and acetone now.
Thanks!

 

[foz]

Re:

Try a small wire brush, a toothbrush isn't strong enough to clear out paint residue or anything that's really stuck

 

[mattr]

Might be some overspray, but more likely to be small particles of bead blasting media wedged in the threads.

 

[Old Ned]

Surprised that Jackson's didn't clean the threads out before sending it back.

 

[FiveAlpha]

Re:

If they did clean the threads, what could be causing the problem? I bought the bike complete, and removed the original bb myself. It was 25 years old, but had never been removed, so I wouldn’t expect thread damage? Or am I missing something?

I’ve never really had this issue, with 20+ other bikes?

 

[hamster]

I've had this kind of thing in the past - as said it's usually blasting residue. Best it to get a decent shop to run a tap quickly through the threads to clean them up.

 

[FiveAlpha]

Re:

Thanks, but as I said, that’s not an option here in Denmark. Wages are so high at the low end, it would cost a fortune. I asked a shop to remove a bottom bracket, because I didn’t have a FAG tool. They said 1 week and 250kr - about £29. I bought a tool for 60kr and did It myself in 3 minutes.

 

[pigman]

Re:

chase the thread through with an old steel cup, no risk to the alloy cup you have