Author Topic: The History of Metrication  (Read 3765 times)

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Offline JohnnyMalaria

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Re: The History of Metrication
« Reply #50 on: August 01, 2018, 03:51:31 am »
But you could buy a 10mm end mill.  Locating a center is somewhat dimensionless in the sense that measurements from both sides use the same units regardless of what they are.

I could but the headaches come from the 1/16" pitch marked in thous and trying to make things in mm. :scared:
A tip to help get your head around it and for quick calcs:
1mm = ~40 thou.
If I had 0.1" or 0.05" pitch instead of 1/16" it would be less stressful. If I have to move 700 thou with 1/10" pitch, it's just 7 turns. With the 1/16" pitch it's 11 turns and then 12.5 thous which may or may not wrapped around the 0/62.5 line which, if turning CCW, then involves subtracting the 12.5 to end up at 50 thous. If that made sense, please explain it to me!


Nevertheless, I'm happy with how the part came out.
Tell me it can't be done and I'll do it. Or give it a damned good try.
 

Offline Keicar

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Re: The History of Metrication
« Reply #51 on: August 01, 2018, 04:09:51 am »
I was surprised to learn the extent to which the U.S. watch industry embraced the metric system in the mid/late 19th century. For example, balance staff pivot sizes are expressed in units of 0.1mm.
 

Offline vk6zgo

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Re: The History of Metrication
« Reply #52 on: August 01, 2018, 06:24:33 am »
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.  :scared:

I saw plenty of UNFs around, but nothing in such small sizes, certainly not obtainable over the counter in Oz, like Whitworths & BA were.
SAE (coarse), is pretty much the same as UNC &  Whitworth, with SAE (fine) pretty much the same as UNF.
(Except where they aren't)

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

Offline vk6zgo

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Re: The History of Metrication
« Reply #53 on: August 01, 2018, 06:33:56 am »
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.

They had LH threads up until 1975.  I used to do a bit of drag racing in my misspent youth, mostly MOPAR.  All of our cars had LH threads.  Wish I still had the cars!

GM used LH lugnuts on certain models up to '65

https://www.hotrod.com/articles/ccrp-0607-junkyard-crawl-lefthand-lugs/

I never was a big Chrysler man, but I'm pretty sure all the Oz built ones in the '50s, '60s & '70s, used standard RH threads all round.
It wouldn't have been a hard mod to make for a manufacturer if they wanted to please the local market.

 

Offline tautech

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Re: The History of Metrication
« Reply #54 on: August 01, 2018, 07:56:15 am »
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.  :scared:

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.

Quote
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.  :rant:

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 !

Quote
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.
Avid Rabid Hobbyist
 

Offline apis

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Re: The History of Metrication
« Reply #55 on: August 04, 2018, 05:59:36 pm »
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.
« Last Edit: August 04, 2018, 06:05:00 pm by apis »
 

Offline bsfeechannel

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Re: The History of Metrication
« Reply #56 on: August 05, 2018, 01:16:42 am »
Yeah. Ironically, sticking to imperial is one of the most un-American attitudes in the perception of those outside the US.
 

Offline rdl

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Re: The History of Metrication
« Reply #57 on: August 05, 2018, 03:43:54 am »
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.
 
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