Metric or Decimal..accuracy?

wrote:


Do grow up, will ya? What did you expect? A big hug and a kiss on a cheek?
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wrote:

Plonk
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To my knowledge the US gallon is based on the old English wine measure and why that was chosen by the US I don't know but is approximately 4/5 UK gallon. Both have 8 pints to the gallon but the US pint is 16 fluid oz and the UK 20 fluid oz although the US fluid oz is slightly larger apparently due to the difference in the temperature the standard is measured at. Beyond that I have never had the interest to investigate the history of the US measure as its of no practical use to me.
snipped-for-privacy@jerseymail.co.uk wrote:

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On 3 Jul 2006 13:41:28 -0700, snipped-for-privacy@jerseymail.co.uk wrote:

No wind up intended. I use the term of art "US Decimal" to indicated decimal inch measurements, since the UK has gone to Metric.
Sorry for any confusion. None intended in this thread.
Gunner
"If thy pride is sorely vexed when others disparage your offering, be as lamb's wool is to cold rain and the Gore-tex of Odin's raiment is to gullshit in the gale, for thy angst shall vex them not at all. Yea, they shall scorn thee all the more. Rejoice in sharing what you have to share without expectation of adoration, knowing that sharing your treasure does not diminish your treasure but enriches it."
- Onni 1:33
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wrote:

The term is "United States Customary System" http://en.wikipedia.org/wiki/United_States_Customary_System
Learn it.
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wrote:

http://www.google.hr/search?hl=en&safe=off&q=%22US+decimal+measurement%22&btnG=Search
Your search - "US decimal measurement" - did not match any documents.
Suggestions:
* Make sure all words are spelled correctly. * Try different keywords. * Try more general keywords.
What do you know?
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And, the British got it from the Romans. The "imperial" part of Imperial Measure refers to the Roman Empire, not the British!
Steve R.
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Apologies to misc. survivalism (I won't ask what that is) and others, I was aiming only at rec.crafts metalworking. Please don't shoot me down for cross-posting, I didn't notice that I'd inherited the OP's inclusion of other groups in his search for the original thread. Regards Ian
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snipped-for-privacy@jerseymail.co.uk wrote:

Don't apologize, you answered the question and it's not really Gunner's fault that the three groups see so much of each other.
TK
--
At the 51st percentile of ursine intelligence.

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Gunner wrote:

Can't really comment on the differences between the two manufacturers in relation to metric imperial/measuring systems. All being equal, they should have both been working within a given set of tolerances, converted or not, and the product should have met those tolerances. If there were major discrepancies between the two shops, perhaps the tolerances were too loose in the first place, or perhaps one shop worked to the tolerance and the other held tighter than specified tolerances as a matter of course.
All else being considered, the metric normally used smallest typical unit used on the shop floor should be the hundredth of a mm, of which there are 2.54 to equal the one thousandth of an inch typycally used when measuring imperial.(1 inch officially being defined in the US as equal to 25.4mm exactly, IIRC).
If a typical measurement were to be given with a a plus or minus 1 unit tolerance, metric should come out closer to a given dimension than imperial.
This of course completely ignores the various protocols for tolerancing based on dimensions given to a certain number of decimal places and the like, as well as the opportunities for conversion errors.
Cheers Trevor Jones
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Gunner,
You ask an interesting question.
Since we are all using machines with the same capabilities and likewise measuring tools, I would guess "more accurate" may have more to do with standards than anything else. For instance what is the British vs. American standard for bearing race tolerance, loose fit, tight fit, press fit parts? Same with but not limited to other standards bearings and threads etc.
Tom
Gunner wrote:

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Thats sort of what I was thinking. THat and "rounding" of small decimal measurements either up or downwards
Gunner

"If thy pride is sorely vexed when others disparage your offering, be as lamb's wool is to cold rain and the Gore-tex of Odin's raiment is to gullshit in the gale, for thy angst shall vex them not at all. Yea, they shall scorn thee all the more. Rejoice in sharing what you have to share without expectation of adoration, knowing that sharing your treasure does not diminish your treasure but enriches it."
- Onni 1:33
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Gunner wrote:

I'm now looking in my (old) book of tolerance tables for Swedish standard. Most standard tolerances are given as whole numbers of micrometers, only the smallest of the basic sizes have tolerances given as tenths of that. Hope this helps.
S.
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Gunner wrote:

U.S. decimal system is based on the metric system in that there is no standard inch or foot. The definition of an inch is 2.54 cm. All length measurements are related to the meter which is defined as the length of the path traveled by light in vacuum during a time interval of 1/299792458 of a second. Accuracy does not depend on the units used in the measurement. You may be confusing accuracy with precision.
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Gunner wrote:

My two cents:
In the late 80's we got drawings for an exotic water-cooled piece of Russian (er, Soviet) electronics.
On the drawing was the spec for the threads used to deliver water to/from the device. It was metric and had 4 decimal places of precision specified.
We start calling local, national, and finally international threaded fitting manufacturers and they say that the numbers do not match up to any known plumbing system.
Then the device actually arrives in the shop and it's obvious: the connector is a perfectly standard garden hose :-).
Tim.
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Tim Shoppa wrote:

LOL
John
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john wrote:

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Mate of mine has worked in Germany quite a bit and said that many threads used there such as pipe and some cycle related threads were of inch origin but metricated so although having a DIN standards the thread pitches didn't fall into the normal pitches prefered by DIN standards. From this many world pipe threads are compatible with BSP but not NPT which is typically 1 TPI out except 1/2 NPT IIRC the difference then being in the Whitworth 55 dgree thread form against the 60 degree form used by NTP.
Tim Shoppa wrote:

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David Billington wrote:

I just machined a housing that the print was in metric... converted from inch. The pipe tap dimensions were in metric for the drill sizes and the pipe taps themselves were 1/4, 3/8, and 1/2 BSPT.
John
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Tim Shoppa wrote:

I'll call this bullshit. Metric thread designation does not have any decimal places for all the standard threads. For special fine threads (and this is definitely not the case here) two decimal places are only possible for something less then M10. For all the plumbing needs inch threads were used indeed. There was also no way that russian designer used some non-standard thread - it was just not possible.
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