The History of Metrication

[tautech]

Another thing is the revival of Whitworth threaded bolts, thanks largely to the massive output of these devices in India, which is largely unreconstructed "Imperial".

You'd really wonder why any modern manufacturer would want to use Whitworth. 
Sure for India it comes from the days of British influence but really in this day and age ? 
OK so they cheaped out on needing to update their tooling but that still leaves them using 19th century technology.

Metric is where it's at, coarse, fine and super fine in most thread sizes.

I've used BSW, BSF, UNC, UNF and most of the pipe threads ever made too, I'll keep BSPT but give me metric for everything else thank you.

I suppose if you're bolting pieces of wood together for a pergola or something, it doesn't much matter!

Whitworth & UNC are, to a large extent, compatible, but I've always hated BSF!
Then there are the other delights--- BA, those weird US thread sizes that Tektronix use that don't seem to relate to anything else much, "Lucas threads".
My old 1936 Chev even used special  "General Motors threads" on the front axle!------aaarrrrrggggghhhh!.

By the way, talking of pre WW2 US cars, anyone remember how Chrysler used LH threaded wheel studs & nuts on the LH side of their cars?

Apparently, it took them a few years to realise that other carmakers weren't dropping wheels higgledy- piggledy, & came back from dreamland.

Well trucks use dedicated 'hand' threads to this day.
BA, that's Pome (correct spelling) while your 'obscure' Tek threads are # UNF threads !

Yet my Aussie built 2002 Commodore is a mis-mash of SAE (imperial) and metric threads. 

I saw plenty of UNFs around, but nothing in such small sizes, certainly not obtainable over the counter in Oz, like Whitworths & BA were.

Yes that's because of our links to the motherland and not so much to the US.

SAE (coarse), is pretty much the same as UNC &  Whitworth, with SAE (fine) pretty much the same as UNF.
(Except where they aren't)

And when the aren't they're flipping miles off.
Dunno how many times I've be caught by 1/2" BSW bolts and attempting to get a 1/2" UNC nut onto it. 

What makes it worse is that BSW hex head and nut sizes have changed from the real old days to where now they can be easy to mistake BSW as UNC.........grrrrrr !

Small screws in metric sizes still generate headaches, with Japanese stuff usually coarse, & German, fine.

I've had quite a bit of experience with Swedish and a little of German power tools where thread sizes and pitches have been quite standardized and no problems with a bit of Jap stuff thrown in too.
3, 4, 5, and 6mm fasteners all quite standard with only some differences to drive types, Hex key or head, Torx, slotted and Posi/Phillips all in universal usage with the occasional anti-tamper thrown in just to keep things interesting.
If you're using fasteners frequently you just have to have a full arsenal of tools to deal with any type.

[apis]

I'll bet this thread gets locked pretty quick.

The US uses metric units for all scientific work but it will NEVER become the standard in the US because the people (that is, the voters) think of it as a "Europe" kind of thing and we're not really into that.  We bailed out of that a long time back.

They got that backwards. The US customary system is essentially the old British colonial system, while the metric system was born out of the same set of ideals upon which the USA is founded. That is the most baffling aspect of US resistance to metrication imho.

[bsfeechannel]

Yeah. Ironically, sticking to imperial is one of the most un-American attitudes in the perception of those outside the US.

[rdl]

I wonder who's fault it really is that America is not more metric. The manufacturing infrastructure? I don't think the general populace cares much. Soft drinks are sold by the liter. Beer is bought by quantity, six packs, case, keg, etc.. Gas is bought either by the dollar or by the tank. Probably length and distance, and weight, would take some getting used to, but I doubt it would be that big of a deal for most people.