Stud Thread size

[R]

I agree that BA is a very logical thread series. 

Given that it was largely metric based, yes. !
Smiths meanwhile swallowed their English (British ?) pride, and used all metric
on the chronometric speedos, for many a year.

But reverted to BA etc on the magnetic Smiths range.
Odd, given that they had all that metric machining capability ?
Nationalism is a strange disease ...

[DM]

Yeah, if you're made of money...
Hardly justifiable for the use-it-now-and-again amateur.

Coventry die heads and dies do turn up for very little money, a few years ago I was given buckets full of new and sharpened die sets from a aerospace company. They had gone over to thread milling and the die sets were headed for the scrap bin.Luckily the owner is a friend and sent them my way.

[Rex]

Smiths meanwhile swallowed their English (British ?) pride, and used all metric
on the chronometric speedos, for many a year.
But reverted to BA etc on the magnetic Smiths range.
Odd, given that they had all that metric machining capability ?
Nationalism is a strange disease ...

Given that the chrono was based on a French Jaeger design keeping the Metric dimensions and specs was likely down to laziness, but that said the French components used "French metric" threads which required conversion to ISO metric stuff in later years.
Seems like even the so-called "universal" metric standards were far from universal even as late as the 1960s.
Given the meltdown of the old industries in the mid 1960s, who can tell the reasons why the reversion to BA threads on the later crap mag speedos, but whatever the reason(s) claiming that some sort of nationalism was the root cause really is nothing short of bizarre....

[R]

nothing short of bizarre....

But true.
Stranger things have happened at sea ...

Fashion in nuts-n-bolts comes and goes.
I've owned a car which had an all metric body and an all imperial engine/gearbox.
And a Commando, which had an all AF/UNF body (mostly) with an all (nearly) imperial engine .
Nationalism has produced some strange bedfellows, thats for sure. !

[Rex]

I would put that down to lack of money to invest in new tooling etc rather than any sort of nationalism, but maybe we just have a different understanding of the meaning for the word....

[iansoady]

I agree not nationalism but I can't see how changing half the threads to UNF/UNC would save money......

The worst thing on the Commando was the back head stud which was 5/16" cycle. It was (and still is) a bugger to get at and a 5/16" UNF "almost" fits until it seizes up after a couple of turns.....

[R]

Well, then you have to ask WHY all the (very) British thread standards emerged, when all the early motoring was done with French engines
- so would have been largely metric . (even if metric wasn't standardized until 1919.)
A bit like really early American cars started driving on the left, but then switched to the right.
These decisions appear on the face of it to be less than entirely logical ... ?

Oh, and an Swiss clockmakers threads used 47.5 degrees, so we can see where BA got that from.
Even if the rest of it was nearly metric, but not quite.

One wonders if patent specifications may come into it somehow ??

Yes that top head bolt on dommies and Commandos was a pain.
I've misplaced the ground down socket that fits, don't tell me I have to do another one.

[Rex]

Well, then you have to ask WHY all the (very) British thread standards emerged, when all the early motoring was done with French engines

The thread and fastener standardisation started by that nice Mr Whitworth started lonnng before the era of of early French IC engines...

[R]

But Whitworth was almost entirely unsuitable for IC engine use.
Apart from threading a few stray coarse threaded studs into aluminium.
And he only standardized a hodgepodge of things.

Clockmakers threads on the other hand go way way back.
Salisbury Cathedral think/claim this is 1386

https://en.wikipedia.org/wiki/Salisbury_Cathedral_clock#/media/File:Salisbury_Cathedral,_medieval_clock.JPG

[Rex]

But Whitworth was almost entirely unsuitable for IC engine use.
Apart from threading a few stray coarse threaded studs into aluminium.
/quote]


You seem to be presuming  the Whit threadform was the sum total of the man's life.
Have a read-
 https://www.whitworthsociety.org/history.php?page=2

His greatest achievement was the concept and start of thread standardisation across the industrial world, and with the greatest respect to medieval Salisbury cathedral, their particular claim is rather a non-starter.

[R]

I'm not denying that, at all.

But if you take a critical look at things, the English (British) seem to have a penchant for taking
others perfectly good thread systems, and 'developing' it into something they can label as their own. !
So we have BA, which is a adaption/mangling of a Swiss clockmakers metric thread, 47.5 degrees and all,
such that present day metric nuts are a (poor loose) fit.
An indication of how closely they copied it. ?  But not copied it exactly ...

I thought you'd be more appreciative of that Salisbury Cathedral clock mechanism.
Even if Mr Whitworth played no part in it.
Engineering was alive and well, post the Roman era !

[R]

I'd also add that in my modest collection of bikes, I think I've previously counted something like
16 different threading systems. This covers a few continents and a fair spread of years.
But thats a lot....

There is a good reason of course why plumbing and electrical and general threads should be different,
so that never the twain shall meet, but ...

A Norton Commando has 7 (or 8 )?  of those.
One I can dismantle with a single 12mm spanner/wrench.

[Rex]

But if you take a critical look at things, the English (British) seem to have a penchant for taking
others perfectly good thread systems, and 'developing' it into something they can label as their own. !
So we have BA, which is a adaption/mangling of a Swiss clockmakers metric thread, 47.5 degrees and all,
such that present day metric nuts are a (poor loose) fit.
An indication of how closely they copied it. ?  But not copied it exactly ...

Took/adapted/developed/whatever....you seem to have some deeper narrative you want to post about.
Do the Wokies know about this alleged thread appropriation? I don't want some pink-haired harpies picking up on your posts and cancelling my BA thread selections.

[R]

Just pointing out the facts of life
Which some obviously never consider

Somewhat akin to some folks will tell you that Harley Davidson invented the motorcycle.
And they mean it...

[Rex]

Always disconcerting when someone says they're only "pointing out the facts", as  most appreciate that those "facts" have a habit of alteration and alignment etc subject to the beliefs of the person stating them.
Strange claims that nationalism was the root cause of a reversion to BA threads in the mid-1960s being a perfect example.