B/B question.Save me some time please.

[Grannygrinder]

Can anybody tell what thread a standard B/B is?
I'm awaiting one with slightly damaged threads,we have hundreds of taps at work,so rather than try them all til i find the right one it would be nice to know in advance.Ta

 

[one-eyed_jim]

1.37" x 24tpi
drive side is left hand threaded

http://www.sheldonbrown.com/gloss_bo-z.html#bottom