Octalink

[faster]

There is play in the threads up until the cups are tightened down, at which point the cups align with the face of the bottom bracket shell. In other to do this, they'll sit slightly skew to the threads if necessary, as allowed by the small amount of play in the threads.

I've got three bikes with external threaded bottom brackets and none have any spacers like you describe. I've just been out to the garage where I've got a brand new in the box Shimano HT2 bottom bracket - again no spacers.

I think that might be a mountain bike thing.

 

[Threevok]

Yes, we we talking about MTB BBs

Sorry for the confusion

 

[C R]

There is play in the threads up until the cups are tightened down, at which point the cups align with the face of the bottom bracket shell. In other to do this, they'll sit slightly skew to the threads if necessary, as allowed by the small amount of play in the threads.

I've got three bikes with external threaded bottom brackets and none have any spacers like you describe. I've just been out to the garage where I've got a brand new in the box Shimano HT2 bottom bracket - again no spacers.

I think that might be a mountain bike thing.

I can't say I have ever noticed any play in a bottom bracket thread after a few turns. The pitch of the thread is quite fine, so there's a lot of threads engaged and the tolerance is quite tight, on purpose, there's not meant to be play.

 

[si_c]

There is play in the threads up until the cups are tightened down, at which point the cups align with the face of the bottom bracket shell. In other to do this, they'll sit slightly skew to the threads if necessary, as allowed by the small amount of play in the threads.

Erm, I'm pretty sure that's not what happens. In my experience you tighten the threads as far as they go - if the shell needs facing then you can see this by there being a gap between the bottom bracket shell and the cartridge/external BB unit. The cartridge doesn't skew on the threads - that would be a catastrophic failure and render it useless, it just stops screwing in.