Screw size/thds question

[lynnl]

I was reading an article in one of the "Projects" books and came across a screw size or thrd term that's new to me.
As an alternative to a 10-32 thead (for a knurled lock nut on a bevel guage) the author suggested a "2BA". I'm familiar with some different thread forms, e.g. Whitworth, acme, square, buttress, etc. and of course metric. But I don't recall ever seeing anything like 2BA. What's that mean?

[Tel]

BA stands for British Association and is a commonly used thread by model engineers in the UK and here in Australia. The tread is based on some sort of metric formula and is generally of a finer pitch and more prototypical appearance than some of the others. The 2BA you refer to actually has a major diameter of 3/16"

you should be able to get some info off Alan Stepney's page;

http://www.alanstepney.info/

or let me know if there's anything you need to know.




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Tel

[lynnl]

Ok, Thanks Tel.

[Thrud]

Lynn

They are not 60* threads - BS is 55* and BA is 47-1/2* (I think - check machinerys handbook they may be the other way around)

[Tel]

2 BA is 31.4 tpi

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Tel