Metric/imperial

Mike's post about a rifle receiver somehow started a very heated argument in my office today about the metric system vs. imperial measurements. My point being that the measuring system doesn't matter, as long as it is comunicatable and intuitive. Roger's point is that metric is so vastly superior in every way that Imperial should be abandoned and not taught in schools anymore. I say people in the US won't change and there is no NEED to change.
1. Why did the USA not embrace the metric system? I remember the hoopla when I was in grade school, then it just died.
2. How did the rest of the world adjust where the US couldn't/wouldn't?
# I'd guess that half of us in the US, in metalworking, use metric regularly if not exclusively. I can't quite THINK in metric, almost but not quite.
One of the Russian immigrant engineers I know once said: "No wonder US win Cold War, you are all brilliant...to be able to use this fu*ked-up system!"

Tom Gardner wrote:
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I am going to use the system my machines are built for. I'm a home shop guy, so my machines are older US industrial machines like a Bridgeport mill. When the used machines are all metric, then we might see guys like us moving to metric.
GWE

On Thu, 24 May 2007 21:55:29 -0700, Grant Erwin wrote:
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Well, US used to have a huge manufacturing base which used imperial, so metric didn't catch on. Now this base is mostly gone, the Chinese use metric primarily, and employ imperial for US orders only. I have heard that often they have parallel production lines, one supplied with M6 bolts and another with 1/4-20 bolts.
Anyway, it should be easier to switch nowadays. I hang around NIST, so I'll try to remember to mention it, maybe they'll get back the enthusiasm and start doing something about it, again :)
    p

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I agree with the machine being a big factor in forcing the primary units
I use old american machines here in canada and i have ran into an issue many times where i need to cut metric threads or similar or i run into metric dimensioned parts.
I am in general measurement bilingual since there are sections of canadian industry where the metric measurements are NOT the actual observed standard even if the standards are all written in metric
i think the best thing to do will be to retire my current lathe for more rigid dual threading one rather than to constantly try modifying the gear train by adding a 127 tooth gear
I also think a DRO that will output in both units will make working in either instead of only one set much easier

nospam wrote:
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IIRC, the USA was among the first nations to embrace the metric system. However, it did so in its own, peculiar way, by declaring the use of the metric system lawful for anyone who wished to use it. Apparently nobody did.
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In most European countries, it was made illegal to use the old systems, they were no longer taught in school, and the benefits of the metric system was preached in all the churches (well, perhaps I exaggerate a bit, but you get my drift). A massive propaganda effort coupled with legal means made us accept the newfangled system.
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The metric system was designed to be convenient to use along with the common decimal system for writing numbers. Thus it scales easily to lower or higher units in the system. A thousandth of a kilometer is a meter, a thousandth of a meter is a millimeter, a thousandth of that is a micrometer.
On the other hand, a thousandth of a mile is 5', 3.36´´. (This is an unfair example, of course, because how often do you really have to know how long is a thousandth of a mile, but it illustrates the principle.)
As long as you work only with inches and thous, you have exactly the same benefits as the metric system provides, and then the systems are equal. But when you have to set your machine to, say, 3/16", and the dials only show thous, you have to calculate that 3/16" is 187.5 thous. The European machinist does not as often have to calculate such things, because all measures are given as mm and decimal fractions of mm.
S.

Sevenhundred Elves wrote: [snip]
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Which is very true; using fractional measure can be a pain. But suppose we had standardised on fractional measure, instead of decimal. It's straight binary fractions! Just right for this digital age. To say nothing of the ease of making a half or quarter-scale model of something.

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Using just your eye, cut something into tenths, but cutting it into halves is easy. And if it's flexible material, just fold it into halves. My real gripe with the metric system is the size of the mm is wrong. It's too big for wood working accuracy. and too small to cut into tens and mark on a ruler. Where 1/64 of and inch is around .015 inches, I can see this with my eyes. I have several rulers where this is marked. To use a metric ruler, and to make a useful eye based measurement, you need to divide the mm by 1/3 so it could be marked and used effectively. Darn, back to bastard non multiple translations by 10's. This all could have been made simple, just define the mm to be 1/64 of an inch. This could be the new imperial metric system. Hee Hee. Ignator

sk wrote:
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Get a ruler with 0.5 mm markings. No problem.
Nick

On Sat, 02 Jun 2007 12:12:30 +0200, the renowned Nick Mueller
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I have one with 0.5mm on the top edge, and 1.0mm on the bottom. The other side has tenths of an inch and hundredths of an inch (about 0.25mm) graduations.
Best regards, Spehro Pefhany

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So now you admit, the metric system is flawed, multiples of 10 don't work. Now fractional mm's are needed to meet human factored use.
some idiot along the way thought the base for this system should be the distance between the north and south pole of an oscillating prolate sphere.
I really don't have any problems with this base 10 system, but it fails when you don't use a physically useful incremental size. This is just as bad as asian lathes using 1/8th inch on feed screws. Ignator

sk wrote:
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Honestly, do you think what you wrote is logic? At least to yourself? It doesn't matter if it isn't logic for others.
Nick

The base ten runs 10^(+/-) 24 power with standard prefix names and is used with SI or any other units.
Dealing with .1 mm is baby talk. .01 mm is how about .001 mm (micro-meter)
I have Imperial drills and Metric drills. My Imperials are from 3/4" to #80 wire. My metrics are in .5 mm and off the top - I can't recall. As I recall it is 10mm to a small drill taking two drill boxes to do it. Hmmm - been a while since I used them.
I use the metric for metric and for stepping between fractional drill size.
Martin
Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net TSRA, Life; NRA LOH & Endowment Member, Golden Eagle, Patriot"s Medal. NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member. http://lufkinced.com /
Nick Mueller wrote:
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sk wrote:
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Even worse, Asian mills that are labelled as metric, calibrated with 150 divisions/turn, so you think the screw is 1.5mm? Try again: it was 16TPI!! Took me quite a while to figure that out...

Nick Mueller wrote:
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So you're advocating the use of 1/2 mm markings. This sounds very fractional, and not so decimal. ;-)

Steve Ackman wrote:
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How about some 1/4 mm and even 1/8 mm markings? :-) ...lew...

2007 02:50:51 GMT, Lew Hartswick wrote:
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I used to be able to fairly consistently measure a diameter to within +/-.002 using the 1/32 scale on a 6" rule. Always within +/-.005 but usually +/-.002.
Stick the 1/64th scale up there, and I could also do it, but it took twice as long. I think once the lines get too close together, it takes longer to "count" them than interpolating between coarser graduations... so I agree with Nick. 1/2mm might be nice, but anything finer than that would just slow me down.

Steve Ackman wrote:
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Thats a joke son , thats a joke. (don't you read smilies?) ...lew...

Jun 2007 14:07:37 GMT, Lew Hartswick wrote:
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I read, I saw, I understood, I thought you would infer the implied, "but on a serious note..."

Tom Gardner wrote:
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Strange how all the science I did in the US in junior and senior high school in the mid 1970s to early 1980s was all taught in metric SI units. I would have had to go to university in the US to get taught poundals and slugs.

Tom, I can't answer your questions, but I can tell you that after using the metric system pretty much exclusively for the last 15 years, I can't even think in imperial units anymore. Even for carpentry work at home, I use metric. My sense of distance is calibrated to millimeters, not inches. Imperial just seems so wacked at all the conversion you have to do to go from one unit to another. (37/64ths is how many thou?)