Metrification in the U.S

Kevin Drum posted this the other day - lots of comments.

Wikipedia article:

Another source:

a mix of both systems is the best except threads
unc unf far superior to a fudged to fit metric thread

Several proposals have been made over the years to adopt and use the metric system for all measurements. Most of us on this forum have the mental capacity to understand and use both systems. Meanwhile, can you please go “pound” sand with your patronizing attitude and snide BS. It’s unbecoming.

I was about to comment on this in the other thread :slight_smile: When I was in the US Army in the 70s, we used metric almost exclusively, except for weight/mass – I don’t know if the US Navy did the same. Most of us got pretty good at translating back & forth (truck speedo in mph, road signs in kmph, etc.), but these days the media seem to have forgotten their earlier enthusiasm for metric and require “english measure” in every article to be read by the public - including some ludicrous translation silliness (“the racer’s top speed of 186.4114 mph…”).

Oh sorry if pointing out facts offends you, but it is a fact that only USA and Liberia hasn’t adopted the metric (SI) system of measurements.
UK and it’s colonies and overseas territories have partially adopted it and use it at least to some extent. Same has Myanmar and North Korea.

Even Puerto Rico and Guam is among those who has almost completed metrication, while USVI, American Samoa and North Marianas follow US system.

Map of countries according to their metrication status, based on [Metrication article (English
Countries by current metrication status (based on official usage only) (2016):
Green: Complete Yellow: Almost complete Brown: Some adoption to partially complete
Red: Little adoption

PS> I cannot promise not to bring up facts again. If it offends, just don’t read my posts.


Singapore went metric in the1970s, but sq.ft is still used as the measure of property.
Some old ladies may still insist on using kati when shopping at wet markets (the stall holder just say “OK Poh Poh” and adjust the order to the nearest eqv. in the metric system)

Facts don’t offend me. Pontificating trolls do.


You’ve probably heard that the United States, Liberia, and Burma (aka Myanmar) are the only countries that don’t use the metric system (International System of Units or SI). You may have even seen a map that has been incriminatingly illustrated to show how they are out of step with the rest of the world.

metric system adoption map

Countries that have not “officially” adopted the metric system (The United States, Myanmar, and Liberia) in gray.

Credit: AzaToth [Public domain], via Wikimedia Commons

It’s a compelling story and often repeated, but you might be surprised to learn that it’s simply untrue!

From the illustration I guess Antarctica hasn’t adopted the metric system though I imagine most of the various research stations uses the metric system more often than not.

I am trying to remember the last time I used any of my SAE wrenches (with exception of those that are close enough to be equivalent). My cars have been metric for over 20 years.


Yes we all agree that the metric system is in wide use in the US and that it was decided in 1975 that the US should go metric:
Metric Conversion Act was signed on December 23, 1975, by President Gerald R. Ford.

IFAIK it was also decided that the metric system should be taught in US schools

I can’t vouch for it being correct, but I remember hearing/seeing/reading somewhere that Ronald Reagan stated that he didn’t like the metric system because; “it is so difficult to remember all those conversions” (1" = 2.54 cm. 1 lbs = 454 g. etc.)
PS> He didn’t cancel the Act, just did not implement it fully.

It is also well know that “dollar divided into 100 cents” was the first use of metrics in any monetary system.

Ronald Reagan did try, but only succeeded in abolishing the Metric Board that was tasked to work out how to implement it:
The Metric Board was abolished in 1982 by President Ronald Reagan, largely on the suggestion of Frank Mankiewicz and Lyn Nofziger.

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Say what you want to say. Be a man of you words.

Tons of imperial engineering is superior to metric. Both have uses
I measure the distance between holes in metric and drill and tap for imperial.
Metric hydraulic fittings and technology, yes a joke
Usable numbers in common engineering also doesnt work in many metric measurements, imperial way easier in lots of cases.
360 degrees or do you want to use radians ( yes I know computers use radians and convert it back for display)
Glad I grew up learning both and still use both.


Let us in on the joke. Does metric fittings leak more than those measured in imperial units?

Which cases ??
If you have to convert metric to imperial units to “understand” them, you haven’t “gone metric” (or v.v.).

Lucky King Henry V decided to use his feet and thumb as standard for measurement, otherwise you may have ended up with measurements like ; “1 stiff = 3 slack”

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I suppose the US hasn’t converted to metric the same reason some folks I know still measure in stone. When I first heard a weight measured in stones I thought it was a joke. Who chose the size stone? Then I was reminded that the foot literally evolved from the size of someones foot. Metric is just logical. Aircraft, ships and other vehicles seem to work quite well with metric threads and fitment. Metric is sure easier to calculate. :slightly_smiling_face:

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You are correct about Antarctica. When working with scientists it was handy that charts I used were 1:100,000. The metric system is used by the seismic industry at sea as well.
In NZ. It is common to give a child’s birth weight in pounds and ounces for grandma.
My vehicles and tractors are all metric but the Bobcat I’m working on at the moment is SAE., except for the engine, a Kobota.

Indeed. SAE takes math skills. 10mm too small, get the 11mm. Not so easy when the 5/8 is slightly too small. And why is a mile at sea different from a mile ashore?


I loved how drillship crews use measuring tapes with 10 inches in a foot, measure weight in kips (a kilopound) and pressure in ksi (kilo pound per square inch.) Biggest argument was keeping the DP system in meters or feet. (I insisted on meters though preferred knots over m/s)

Ever wondered why lathes and other machining equipment weren’t measured in 1/64th inch or less, perhaps they knew something. Do Brits graduate stones in pebbles? I think they revert to a decimal of a stone for smaller measures but in 2022 it is silly to even discuss this, What’s next? Cubits? :grinning:

Right. What’s a cubit?


On one drilling rig working in Australia (after Oz had gone metric) they had a measuring stick that was marked in meters, but each meter was divided in inches.
It was a funny to listen to the Toolpusher reporting to the Companyman (both good ol’ boys from Texas) the drilling progress in meters and inches.