That state of metric conversion in the US

Feb 16, 2013 327 Replies

Obviously one page was intentionally blank and the other was an accident. I hope no one lost their job over that! lol

Rick

I'm sorry, I don't quite get this. What is 4 mm in fractional inches? For that matter, if I want 0.1 inches what standard fraction should I use?

Rick

The difference (between socket and driver) is less than 0.2mm on a

1/2" socket. A 12mm driver would more than quadruple the slop. Might not be healthy if you're trying to free a frozen bolt.

It's not just spending the extra bucks once, I'm quite willing to do that (and have with some machine tools), it's the continuing supply of a wide range of metric sizes of cutters, taps, reamers and such like that causes hassles. I've actually gone backwards (more inch stuff)- with calipers and micrometers and DROs that switch, it's not so bad. I'm certainly not going to try to find boutique suppliers of A4 paper and fittings for whatever Europeans use instead of NPT threads. It's not like the inch numbers mean much anyway.. 1/4-NPT is 0.54" diameter, for example. At least the TPI numbers mean something. The taper is 3/4" per foot. ;-) And chucks etc. use JT tapers and Morse tapers and R8 tapers, which are inch. It's a dog's breakfast. 20 gauge stainless sheet is thicker than steel, which is thicker than aluminum.

I'm sure the metric tools are cheaper and more available than inch are outside North America, but I'm not there. Somtimes I'll bite the bullet and pay 100x the going price for metric fasteners when something is going to be assembled offshore. .

It's nice to have the imperial units sometimes.. for some applications, BTU/hr*ft*°F might be just the ticket. But usually I find the metric makes life easier. Living in both worlds gives a bit more variety in things at times too. Letter size drills, drill wire gauge sizes, metric drills, fraction inch drills- there's bound to be something that makes a hole I can live with.

Best regards, Spehro Pefhany

"it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com

Two

in

pounds.

Most common kitchen cooking ingredients, within a few percent.

?-)

Sure, but nowhere near as accurately as 1 imperial gallon = 10 lbs of water. PS in the UK a pint isn't a pound. ;)

Cheers

Phil Hobbs

Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net

We are using Lambert projection in VFR aviation charts, so a plotter (a special ruler) works well without need to go to the latitude scale. Also, the great circle heading can be taken directly from the chart.

Here, at 60 degrees North, the longitude scale on a Mercator chart is just half of the full measure.

By the way, both captains (Mercator and Lambert) were teaching at the Amsterdam Institut for Navigation, quite some time ago.

Tauno Voipio

Yes, that is handy for air navigation. I was a blue water navigator where plodding along at 300 nm/day was pretty typical, and a rhumb line approximation to a great circle route was good enough. Hell, being able to make a rendezvous point and "only" being off a mile or so was good enough... ;-)

First I've heard of non-alphameric characters in license plate numbers. I wonder how other states handle it in their software? The strangest thing I've seen here on license plates were Auburn and LSU logos (on GA plates). GA and GA Tech, I understand but the competition? I guess if they can get you to volunteer $25/yr to the treasury, why not?

Once is enough to ruin your whole day.

Larger opportunities!

A host is a host from coast to coast.................wb8foz@nrk.com & no one will talk to a host that's close........[v].(301) 56-LINUX Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433

Are you talking about the socket that fits the bolt or the square drive hole in the socket that fits the ratchet? I agree that a socket has to properly fit the nut, mainly because the corners are easier to round off especially when using a 12 point socket. But the drive hole is square and much more robust. I seriously doubt that 0.35 mm of extra clearance is a problem for a 1/4 inch drive socket or an extra 0.5 mm clearance on a 1/2 inch drive socket.

Last time I checked, I could buy tools from anywhere. But I don't often use pipe threads and machine shop tools, so I'll defer to you on this. My point is that unless you are close to retirement, it is a losing proposition. Pay me now, or pay me later...

I don't know what ticket that would be. I'll be a very happy guy to see the measurement system we are using go the same way as British money.

Rick

But a pint is *exactly* 16 fluid ounces...

Rick

In the UK "A pint of pure water is a pound and a quarter".

Rick

Wait a minute. If they went metric, they wouldn't be using nautical miles either...

Speaking of that, I believe the reason they use nautical miles is because it is approximately (pretty close actually) to one minute of longitude at the equator or latitude anywhere. I guess that comes in handy. While verifying this I found a very interesting page that explains the origin of the term "knots".

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Rick

Re: jokes,

I must say, I'd rather be drinking this Russian Imperial Stout than, say, a French Metric Porter. Mmmmm, nummy.

Tim

-- Deep Friar: a very philosophical monk. Website:

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They don't want to bleed you dry perhaps?

I don't see what you're getting at...One US fluid ounce of water is about 1.04 ounces avoirdupois, not 1.00.

Cheers

Phil Hobbs

Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 USA +1 845 480 2058 hobbs at electrooptical dot net http://electrooptical.net

in

s.

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Sure but +/-5% is good enough lots of times. I've used 8lbs in a gallon which is ~231 cu inches.. and an acre is ~22,000 sq feet. Lots of silly non-metric coversion factors are stuck in my head.

My personal 'system' gripe is with temperature. Everyone should learn Kelvin right off... about 296K in my house now. Having negative temperatures is silly. Like you would be negative feet tall till you reached five foot. (Hmm still working on distance, metric-wise.)

George H.

were

doing

Some are a bit gross though:

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Then the macabre ones:

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Regards, Joerg http://www.analogconsultants.com/

Ask a crook for a pinch..

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