Problems with powder coat
 

I just got my SLT 12.2 back from pc and i am running into some problems. I had them tape the bb threads after blasting and before coating. They looks fine. I took a chain saw file and scuffed the pc on the faces of the bb shell. I then got both sides threaded in and when the lock ring is fully tightened and on, the spindle is way sloppy and has far too much play in it. It wont sinch up like a typical bb should.

WTF do I do now? I dont see a way around this....and I am confused to why this problem is occurring. I really cant afford to dump any more money into this build.

Did you scuff the face until all the pc was gone, so the the BB width is not larger? A millimeter or two could be throwing it off.

One solution is to just go with a modern cartridge bottom bracket. Shimano units start at $10 or so for a UN26 and a UN54 can be had for $25 or less. I have used both on projects.

The fixed cup needs to be able to get to the same depth as before the PC, so as per kalifornsky you need to be sure there isn't a build up on that side. If that is OK, the PC should not have had an impact on the adjustable cup - are you sure you tightened it up enough? Did some grit get in the threads on that side?

Mark

BTW: I hope the powder coat isn't 1-2mm thick on the BB!

Mark

haha, i was being a bit excessive!

I actually didnt completely take all of it off. It's kind of spotty (off in a couple areas, thinned in some, and etc.). So I need to get the faces completely naked of pc? I remember the shop facing the crown race and head tube on another frame I has coated and the stock headset would not fit, it was too small after the facing.

You dont need to see the faces and to be honest, I probably would have left it alone. For whatever reason, 1, or both of the cups isnt threading in all the way.

If the cups aren't threading in all the way, that's your problem. Ideally, a well-equipped shop or home mechanic would chase the threads and face the ends of the BB after a paint job. See if you can clean the threads inside the BB with a very stiff wire brush and clean all the paint off the faces with a file.

+1 Inspect threads.

Are you using antiseize on the threads?

Do you have good bb tools?

Don't force it, a shop should be able to do it for you for very little $$.

First off, what do you mean by, "when the lock ring is fully tightend"? The adjustable cup has to be snugged down to take up any play before the lock ring is tightend. Are you saying the adjustable cup is going in too far to leave any threads for the lock ring, or are you saying the adjustable cup is not threading in far enough to take up the slack in the bearings?

If the adjustable cup is going in too far, then face the fixed cup side and or check that you are using the right size ball-bearings.

If the adjsutable cup is tightening up before the slack is out of the bearings then chase the threads so it can reach the proper depth for adjustment.

Unless something is keeping one of the cups from going in far enough, try over-tightening the adjustable cup so the spindle turns a bit hard before tightening the lockring. When the lockring tightens against the BB shell ,the adjustable cup will be pulled out a little due to the tolerances in the threads. If you tighten the adjustable cup so the spindle turns smooth & then tighten the lockring, you're going to have some play. It's a trial and error thing.

I have overauled countless bbs in my lifetime. The fixed side tightens nice and snug against the bb face. THe adjustable cup threads in all the way and when it is threded in all the way, the spindle still does not want to tighten. I am nearly certain I am using the correct size bearing, but I cannot remember off the top of my head what size they are. They are brand new but I will check size comparison with the old ones. I am stumped here for some reason. Thanks for all the help though. I feel like it has something to do with the facing of the shell, but most of me wants to think that it wouldn't really matter.

You must be missing something obvious, since this is not the first time you've done this job....are you using all the original pieces you took off prior to the powder coating? If you changed things that could be the problem, or have you forgotten any parts? I had trouble getting the adjustable cup on my AO-8 to have enough threads for a lockring when I reassembled it, turns out I had somehow managed to add a spacer under the fixed cup that wasn't there originally (I assumed it was since it was with the parts when I went to put things back together...). Spacer removed, no more issue.

Betcha the bearing size is too small. If you're still using bearing cages, are they oriented properly?

Go back to what you took out (or measure and compare against the new ones you are trying to install).

No way the PC or any facing -or lack thereof- would alter the width enough to result in your description.

Loose ball bearings, 1/4 inch. Change them out and see how that works. 11 per side is the usual count.

Problem fixed. It was the bearing size. I do not have a ruler with the ball bearing measure on it but they were too small. But now I have a problem with the headset...I am going to post a new one about that.