one for the woodists , what are these called?

[timgunn1962]

M5 is the closest common "modern" size to 2BA.

If you need quick, Screwfix list M6 tee nuts, 9mm long, and are showing stock local to me. YMMV.

 

[Agroshield]

Hardly obsolete.

Please supply a more appropriate term if that one is not to your liking.

The word is not meant to be dismissive or critical, but BA threads have long been superceeded in all mainstream uses.

 

[Martin-Sy]

BA's a great thread - probably my favourite. Mathematically a good idea (though it got a bit bodged between theory and practice) and ergonomically I find it very pleasant to use when applying fasteners. I use it on my own projects a lot.

+1

 

[RobCox]

BA's a great thread

Metric, isn't it!

0BA = 6mm x 1.0mm pitch, multiply by 0.9 for every increment in BA size. Hence 2BA = 4.86mm OD, 0.81mm pitch, hence M5x0.8 being quite close.

One real difference being the 47deg thread angle as opposed to 60deg.

 

[arther dailey]

interestingly as I went through my appreticship to be an armature winder first proper set of spanners I bought were a set of BA , later on got 2ba nut spinner..still have the spanners , 54 years and going strong albeit rarely used these days