You could say Napoleon introduced the metric system since he was the de facto leader of France when it was introduced there in 1799.
From 1795 1 kilogram was defined as the mass of 1 liter of water but a 'prototype' kg made from platinum was introduced in 1799 so prior to this there was no other way than to use 1 liter of water.
A Swiss immigrant by the name of Ferdinand Rudolph Hassler brought a copy of the kilogram and the meter to the USA in 1805. Since 1830 and with Hassler's help US Customary Measures are defined by metric measurements. Hassler was the first US Superintendent of the U.S. Survey of the Coast and U.S. Superintendent of Weights and Measures.
currently the meter is defined in terms of the speed of light. it's almost a trick, we define the speed of light to be exactly xx in m/s. A meter is then defined as 1/xx of the distance light travels in 1 sec. I think 1 sec is defined by cesium energy levels.
It didn't start out that way though...
"The metre was originally defined in 1793 as one ten-millionth of the distance from the equator to the North Pole along a great circle, so the Earth's circumference is approximately 40000 km. In 1799, the metre was redefined in terms of a prototype metre bar (the actual bar used was changed in 1889). In 1960, the metre was redefined in terms of a certain number of wavelengths of a certain emission line of krypton-86. The current definition was adopted in 1983 and modified slightly in 2002 to clarify that the metre is a measure of proper length. From 1983 until 2019, the metre was formally defined as the length of the path travelled by light in a vacuum in 1/299792458 of a second. After the 2019 redefinition of the SI base units, this definition was rephrased to include the definition of a second in terms of the caesium frequency ΔνCs."
"The metre was originally defined in 1793 as one ten-millionth of the distance from the equator to the North Pole along a great circle, so the Earth's circumference is approximately 40000 km. In 1799, the metre was redefined in terms of a prototype metre bar (the actual bar used was changed in 1889). In 1960, the metre was redefined in terms of a certain number of wavelengths of a certain emission line of krypton-86. The current definition was adopted in 1983 and modified slightly in 2002 to clarify that the metre is a measure of proper length. From 1983 until 2019, the metre was formally defined as the length of the path travelled by light in a vacuum in 1/299792458 of a second. After the 2019 redefinition of the SI base units, this definition was rephrased to include the definition of a second in terms of the caesium frequency ΔνCs."
USA was supposed to have gone Metric in the late 70s. They started putting dual Metric/Mile per hour signs on interstate highways. Speedometers on cars had dual markings (and still do).
Canned goods were (are) marked with both LB/Oz and mL. We were supposed to eventually make the English markings smaller and Metric larger until the metric dominated. And finally eliminate the English units.
Then someone decided old people would have a problem converting and a big brou-ha-ha put an end to conversion when it became political.
Has anyone mentioned Whitworth?
Canned goods were (are) marked with both LB/Oz and mL. We were supposed to eventually make the English markings smaller and Metric larger until the metric dominated. And finally eliminate the English units.
Then someone decided old people would have a problem converting and a big brou-ha-ha put an end to conversion when it became political.
Has anyone mentioned Whitworth?
I wouldn't consider it political regarding the USA converting to the metric system. It was more about money.
When I began my machinist apprenticeship back in 1984, some of the manual machine tools had metric and EnglishAmerican dials. Whenever we got a metric drawing, we sat down and converted to English/American measurement units because all our measuring tools were English/American. Not saying we didn't have metric micrometers/calipers, etc., but we were issued English/American calibrated measuring tools.
No longer an issue today. All CAD/CAM software can use metric units, in fact the software defaults to metric units. CAD/CAM software calculates speeds and feeds in metric units. There are online calculators for metric threads/gears all over the internet. Units of measurement for metric or any other system is all there. It's easy to change your speedometer to read in kilometers per hour or miles per hour. Today, most machinists have metric micrometers and calipers. Most CAD models are drawn using metric dimensions.
When I began my machinist apprenticeship back in 1984, some of the manual machine tools had metric and EnglishAmerican dials. Whenever we got a metric drawing, we sat down and converted to English/American measurement units because all our measuring tools were English/American. Not saying we didn't have metric micrometers/calipers, etc., but we were issued English/American calibrated measuring tools.
No longer an issue today. All CAD/CAM software can use metric units, in fact the software defaults to metric units. CAD/CAM software calculates speeds and feeds in metric units. There are online calculators for metric threads/gears all over the internet. Units of measurement for metric or any other system is all there. It's easy to change your speedometer to read in kilometers per hour or miles per hour. Today, most machinists have metric micrometers and calipers. Most CAD models are drawn using metric dimensions.
what gets me twisted isn't the stuff you see everyday (2liter bottle of soda, but a 12oz can since you get used to it). it's stuff like purchasing 2 yards of landscaping mulch, 4 board feet of nice hardwood, 2 by 4 lumber that isn't 2" by 4" but a sheet of plywood is 48" by 96", cords of firewood.
Most British cars, motorcycles, airplanes and machinery used Whitworth thread forms right up to the 1970s!
Four families of British threads were developed:
BA (British Association) - a miniature series.
BSW (British Standard Whitworth) - a course thread series.
BSF (British Standard Fine) - a fine thread series.
BSC (British Standard Cycle) - a thread series designed for use on cycles.
Copper tubing is specified by its own kind of sizing (i.e. nominal, not actual), and so is plastic pipe. It just so happens that the systems are different for both. However, plastic pipe, steel/stainless steel pipe, and copper/brass/bronze Schedule pipe are all typically on the same schedule (which is neither actual OD nor actual ID), as long as none of them are "tubing" (since tubing is always defined by actual OD except in the case of sweat-style copper piping). For what it's worth, hose is almost always defined by actual ID.
Clear as mud?
Above is applicable to NA but probably not to other places.
See the API schedules, and ASHRAE standards, most are followed world wide.
JIS, BS, DIN, GOST and others are broadly similar.
JIS, BS, DIN, GOST and others are broadly similar.
Tip of your lttle finger to the tip of your thumb. Perfect solution still in use. Just ask Mr. Ed.
Some machine screw trivia....
Here's the formula to determine a screw diameter from the screw number:
.060"+(.013")*screw number
#0 screw is .060"
#2 screw is .086"
#4 screw is .112"......etc
......and if you look at tap drill sizes, the tap drill for the next screw size up is very close to the OD of the next smaller size screw so that if you strip some threads the next size tap drill will just remove everything for a fresh start.
so for all the metric screw people out there, there are some smarts built into the inch system....
Here's the formula to determine a screw diameter from the screw number:
.060"+(.013")*screw number
#0 screw is .060"
#2 screw is .086"
#4 screw is .112"......etc
......and if you look at tap drill sizes, the tap drill for the next screw size up is very close to the OD of the next smaller size screw so that if you strip some threads the next size tap drill will just remove everything for a fresh start.
so for all the metric screw people out there, there are some smarts built into the inch system....
I don't think the inch worm has ever been used as a standard measurement. Probably because it continually changes it's length.
I deal with Whitworth all the time, it's perfectly fine. What slows me down is Air Ministry Hydraulic fitting materials and standards.
Why did the English have "right hand drive"?....something I read, it had something to do with having the "Sword hand" free...to swing against your "opponent".
---------------------------------------------------------------------------------------------------------------------------------------------------------------------Rick...
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Actually, I think that's correct. Started with horses, carried over to cars.
In the U.S. on long wagon trips, the wagoneer would ride half the time and walk half the time. The idea was that would tire both horse and driver by equivalent amounts. Thus a horse would not be accidentally driven to death. A good idea when crossing the plains.
Of course the wagoneer being right handed would keep to the left of horses to keep a strong right hand on guiding the horse or horses. Thus the driving on the left side practice.
Does this mean left side drivers are descended from life is valuable folks and the right siders are descended from killers?
Of course the wagoneer being right handed would keep to the left of horses to keep a strong right hand on guiding the horse or horses. Thus the driving on the left side practice.
Does this mean left side drivers are descended from life is valuable folks and the right siders are descended from killers?
I was said america indians were riding at the rigth side of the roads and they climb on the horses by the rigth side as well ...while I dunno on what side the wheel is !
The horses that came in this continent by boat from Europe in the XV° century were naturally running on the rigth side of the dirt highways !
I always wondere what sytem was chosen for the screws of the international space station ?
The horses that came in this continent by boat from Europe in the XV° century were naturally running on the rigth side of the dirt highways !
I always wondere what sytem was chosen for the screws of the international space station ?