Bottom Bracket troubles. Please help!
 

Hi! New to the forum that I've been reading for years.
I have an old panasonic frame which i built up to my first fixed gear. I've been riding on it for about a year and i've only recently noticed that my bottom bracket keeps getting loose.
Both cups are tight, i've put sufficient torque on each. But after about a mile of riding my bb keeps loosening. The wiggle is horizontal and at the bottom bracket, NOT the crank arms. I've tried everything, including teflon tape. The frame threads don't seem to be ruined, but if anyone has had a similar problem or has some recommendations that'd be awesome. Thanks!!

hmm...it's a loose bb or a cartridge? If it's a loose one it could have pitted or something. I would recommend buying a cartridge one. Shimano UN54 works alright and can be had for like $25

Is the play between the cups and the frame, or between the axle and cups?

I'm assuming the former. The BB shell may have become ovalised...

So the cups can wiggle in the threads before you put the BB together?

It's a sealed cartridge bb, the play is between the cups and the frame, and right after i've installed it it locks up nice in the frame so i don't think its ovalised. I've just put in a new cartridge this morning so I'll keep you posted after my ride today. (just really hope i'm not out 30$) Thanks for the help!

If you have the sealed BB with the plastic cups, make sure that it isn't cracked.

The bb shell can't be ovalised. There would be evidence of thread damage for that to happen. I doubt the OP is putting the required torque on the cups it's 30nm+ with grease on the drive side anyways.

Now let's get some useful information of the op:

1) Specific bottom bracket he's using
2) BB shell width

+1
I'm wondering if the cartridge is (was) too narrow for the shell.

Okay, well a whole work week of mashing back of forth on a new bb and it seems to be holding up fine. Of course then again I teflon taped the ***** out of it. I'm thinking maybe the bottom bracket threads on the drive side were just worn somehow? Strange but thanks for all the help! Happy riding!