Where does "Mil" come from 1

[swertel]

As general office discussions go, this one is always one that I couldn't find the history on.

A mil is 0.001 inch. Why is it called a mil? Is it a millionth of some unit? Is it of Latin or Greek origin?

--Scott

 

[JAE]

And a millimeter is 1/1000th of a meter. I suppose its not related to "million" but rather a latin or greek phrase relating to 1000.

 

[swertel]

I posted this in the Mechanical Engineers forum also. It seems that "MIL(LE)" is Latin for thousand.

 

[JAE]

A MIL(lion) thanks.

 

[PBe]

Hi,
here in Sweden we use the unit Mil, and thats the same as 10 kilometers
PBe

 

[MASSEY]

Hey, I know this thread is old, but I just discovered it.

http://www.unc.edu/~rowlett/units/dictM.html

explains that mil is an alternate spelling of mill.

In 1791 the US congress established that there would be 10 mills in a cent, and 100 cents in a dollar. So a mill was 1/1000 of a dollar.

Monetary usage is now obsolete, but a mil still represents a proportion equal to 1/1000 which is also equal to 25.4 microns.

Hope this satisfies your interest.

 

[iaguy]

I'm not so sure that the monetary rate that Massey describes is obsolete. My property tax rate is in mils/dollar value.

 

[nicholas123]

I don't know what your all talking about 0.001" is a thou and 0.0001" in a tenth - every engineer knows that!!

 

[poetix99]

Millipede - a thousand footed bug

Millenium - a thousand years

Million (perhaps) - a thousand thousands?

Grazie mille - a thousand thanks

The possible incongruity of "million" aside, "milli" means thousand, or thousandth.

BTW, where I work, when I refer to a "mill" instead of "a thousandth (of an inch)", people look at me as if I have two heads. This might be a peculiar "linguistic island", but my point is that mil is not universal.

 

[BJC]

one mil is .05625 degrees, or there are 6400 mils in 360 degrees. Are they the sam mil and mill? Where did the angular mil come from??

 

[SirAl]

I have seen this unit expressed several times and I wish it was not used! I practice in an area where imperial units and metric units are used. A MIL has been used to express 'a thousandth of an inch' in imperial measure. I have seen 'MIL' specified for products, etc. (e.g. poly vapor barier) on projects designed by and large using metric units. Further, MIL is an acronym for other units of measure including angular measure (i.e. 1/6400 of a revolution) and volume measure (i.e. 1/1000 of a litre).

 

[esf]

And M is the Roman numeral for one thousand.

It is quite common to see gas flow rates in Mcfd which is 1000 cubic feet/day, and MMcfd (one million cubic feet/day)

 

[Binary]

Just for the international flavor, "mil" is also Spanish for "thousand"

 

[torch]

We use "mil" as an abbreviation (slang) for millimeters i.e. if we say it measures 50 mils - it means it measures 50mm.

 

[BJC]

I found this write up explaning for circular mils in 360 degrees.

http://www.boomershoot.org/general/mils.htm

There are 2 pi radians or 6.28 radians in a circle or 6,280 thousands of a radian in a circle. The army rounded it up to 6,400.
The reason I remember for using mils was clarity and speed in communications. Instead or telling someone to elevate their field pice 46 degrees-34 minutes you could say 827
mills. Another one of those things where close is good enough ( like horse shoes, hand gernades and atom bombs)

 

[Binary]

Torch, be careful when new people come in. I think most US engineers and machinists would assume you meant "50 thou" if you said "50 mils"

 

[Skogsgurra]

A lot has been said about mil, thou, inches and millimeters here. But do you know how the relation 1 inch = 25,4 mm came about?

It is one of the first de facto standards that later was accepted as an official standard. Here is how and why:

Henry Ford needed accurate measurements and also standardised measurements in his mass fabrication of motor and other car parts. If he didn't have a standardised measure in all his factories, then the pieces wouldn't fit. Actually, mass production could not exist without standardised measures. So Henry Ford asked the Swedish inventor Carl Edward Johansson to deliver end-gauges (aka Joe-blocks) to Fords factories. Johansson was willing, but there was no fixed relation between inches and millimeters - the NBS was working on it and the Congress also had a say in this matter.

The Congress could not decide - there were a lot of different inches around and each congressman thougt that "his" inch was just right and all the others were more or less wrong, so there was no deciscion in the Congress - and no official relation between the inch and the millimeter in the NBS.

This went on for years, and Henry Ford got more and more irritated. At least he told Carl Edward Johansson to make the end-gauges to a convenient and rational measure and CEJ chose 25,4 mm to an inch and delivered the blocks. And ever after that an inch equals 25,4 mm.

CEJ had a reason to chose 25,4; it allowed to switch from metric to imperial threads in a lathe by using two wheels with 100 and 127 cogs on them. 25,0 mm had been too far off what was used in most states, but 25,4 was close enough to the majority of inches.

 

[Skogsgurra]

Correction: "at least" read "at last"

 

[torch]

Thanks Binary.
I'll be careful if I'm ever in the US.
I live in New Zealand - ex South Africa. Both countries are pre-dominantly metric. (I say pre-dominantly because the old "obsolete" imperial system of measurement does still creep in in some areas.)
The abbreviation "mils" for millimeters is commonly used in both countries.

 

[kanggadget]

Dear skogsgurra,

Thanks for your valuable information.

There is a conflict with what I know.
According to the document titled "The Edison of Sweden : C.E. Johansson and the 'Standards of Standard'" written by Goeran Ahlstroem, C.E> Johansson contacted Henry Ford by letter, offering his collaboration.
Ref:

http://www.ekh.lu.se/publ/lup/71.pdf

I am very much interested in Johansson's contribution in metrology.
Could you please let me know the reference where I can get more information on "inch-mm conversion history"? The thread of yours is the only information on inch-mm conversion history I have.

Thanks in advance.