Isn't it the matter of personal preference and having a drawer FULL of assorted taps and dies collected over the years------AND the wherewithal AND the ability to sharpen them?How many people use the BA hardware in their engines? Wouldn't it be easier, in terms of standardisation, to use the closest metric or imperial thread form?
A lot of model engineers use 47.5 degree BA threads, they also scale better on models.Isn't it the matter of personal preference and having a drawer FULL of assorted taps and dies collected over the years------AND the wherewithal AND the ability to sharpen them?
Years ago, I built a Quorn. The stones are held in arbors which are held on to a high speed spindle- of exactly ONE inch but everything is held on with 1/4 BSF AND 2BA.
Why change-- and negate ALL this work?
But I went to a show at Doncaster and a firm was flogging Myford Tee nuts for less than I could make them and I bought a heap- plus a baby rotary table(. digressing). There was something wrong, the 1/4 BSF studding wouldn't fit. It turned out for them to be tapped M6.
Somehow, I have a very cockeyed 'modern' Myford Super 7-- which cost the earth-- and is in Imperial Measurement but is probably held together with Metric fasteners.
Answer therefore is :-
As experience widens- and mine has been playing with mechanical things for perhaps 87 years now- who bloody cares?
For information, REAL locomotives were held together- with the nuts and bolts which were the ones which someone had obtained.
But, but the British Lords of the Admiralty in their infinitive wisdom made nut heads so big that the brawny sailor boys- couldn't twist the heads off.
Come WW2- to save on metal- the heads of bolts--were reduced in size.
Laughingly, I was about all these changes- like car engines with holding down studs with one end BSF and the other UNF. And the darling Japanese not only copied all this- but drilled the cylinder heads-- to match the pre-War 'British A Series heads and blocks.
Err, next question?????
And Shakespeare actually invented words. Not quite inventing 'rude mechsnicals' in Midsummer Night's Dream but you get the idea. And wasn't a Geordie/Makkem responsible for the Lexicon???????. Alice's Dad!Somebody switch me off....