Streetwise

Units of Measurement and Representation

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Growing up in America, I learned and used imperial measurements, but also metric for science, track, plus all the different numerical representations for computer science, (my favorite is probably a ratio in Common Lisp), and a few necessary sailing units. Canada was right next door, so we had some other metric training. Later, I learned units for HTML and CSS.

I used to wonder why metric wasn't adopted universally where it was an option.

I was searching to re-read the piece mentioned in this thread.

Here it is, plus some other cool pieces on the topic I found along the way.

http://briontoss.com/index.php/2017/12/11/the-metric-system-pidgin-measurement/

https://maticjelovcan.wordpress.com/2016/05/03/in-defence-of-imperial-system-of-measurement/

https://medium.com/@jamestmarriott/in-defence-of-imperial-measurements-16ebde8ad3a5

I thought it would be cool to discuss this further. I think unit choice is more nuanced than I used to.

Music is also an interesting part of this topic.

Cheers

 

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Brion Toss's (RIP) blog post is very interesting -- I read that about 3 months ago.  I listen to This Week in Virology, where at the start all the folks report their local temperature -- usually in F and C -- but sometimes in Rankine, which is the Imperial absolute temperature scale.  It's all kinda arbitrary, just need to pick a standard that stays constant.

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I'm a fan of "Flexible accuracy". As long as every thing fits, with no gaps, it's good.

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5 hours ago, Rushman said:

Decimal inches... Can anyone explain why these exist?

USA Land surveyors use these a lot. Not sure if that is why they exist though.

 

 

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22 minutes ago, Pipe Dream said:

USA Land surveyors use these a lot. Not sure if that is why they exist though.

 

 

Yeah........same guys who invented township and range..........when I was learning map reading at first I just scratched my head. After lots of years it was second nature. We used to have a saying that all large fires start at the intersection of 4 quads........at night........

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5 hours ago, Rushman said:

Decimal inches... Can anyone explain why these exist?

Ever do any machining?

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28 minutes ago, Pipe Dream said:

USA Land surveyors use these a lot. Not sure if that is why they exist though.

 

 

They use decimal feet don't they?  Along with the Rod, which is 16½ ft out I remember correctly?

That gets confusing if you're not used to it.

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For longer distances surveyors used to use chains,  a chain being 66ft, that's the distance between two sets of stumps on a cricket pitch.  Most railways were measured in Miles and chains 

In primary school we were taught,  inches,  yards,  rods, poles and perches,  chains, furlongs  and miles. 

Oh and 4 farthings to a penny,  12 pennies to a shilling, 24 pennies to a florin,  30 pennies to a  half crown,  sixty pennies to a crown,    20 shillings or 240 pence to a pound.

A rod pole or perch being 1/40 of a furlong. Yes 16.5ft

But secondary school worked in metric.

I worked on radar,  the electronics and radar pulses were all calculated in metric quantities,  but the screens were set up on nautical miles. 

The USA signed the metrification convention in 1875, the UK didn't sign until 1884 even though a UK company made the original metre standards. 

Everyone uses metric measurements whether they realize it or not.. Why?

Because from 1959 the inch is defined legally  around the world, including the USA as.. 25.4 mm

I know all sorts of useless information on measurement.. Because... 

I'm a metrology technician ( electronics ) ,  metrology being the science of measurement.. 

 

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5 minutes ago, The Q said:

For longer distances surveyors used to use chains,  a chain being 66ft, that's the distance between two sets of stumps on a cricket pitch.  Most railways were measured in Miles and chains 

In primary school we were taught,  inches,  yards,  rods, poles and perches,  chains, furlongs  and miles. 

Oh and 4 farthings to a penny,  12 pennies to a shilling, 24 pennies to a florin,  30 pennies to a  half crown,  sixty pennies to a crown,    20 shillings or 240 pence to a pound.

A rod pole or perch being 1/40 of a furlong. Yes 16.5ft

But secondary school worked in metric.

I worked on radar,  the electronics and radar pulses were all calculated in metric quantities,  but the screens were set up on nautical miles. 

The USA signed the metrification convention in 1875, the UK didn't sign until 1884 even though a UK company made the original metre standards. 

Everyone uses metric measurements whether they realize it or not.. Why?

Because from 1959 the inch is defined legally  around the world, including the USA as.. 25.4 mm

I know all sorts of useless information on measurement.. Because... 

I'm a metrology technician ( electronics ) ,  metrology being the science of measurement.. 

 

Not just surveyors........but in all fairness we borrowed it from them.......:lol:

Since we don’t have time to accurately measure that distance on the fireline we have a method for rough approximations. I’ve never found it very accurate but......we still teach it.

https://www.nwcg.gov/course/ffm/vert-horiz-and-slope/46-chain-pace-walking-a-chain

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7 hours ago, Streetwise said:

I used to wonder why metric wasn't adopted universally where it was an option.

 

 

I always find this topic fascinating.  In the end, it's just a stick.  The imperial system has multiple sticks, you pick which stick best fits the application.  If I have one gripe with SI measurements, it's that there is just one stick for all.  Measuring distance, there is the Meter, that is it.  Whether something is going to the moon, or going into a drawer, you have the Meter.  "But, but, but Karl, what about the kilometer, decimeter, millimeter?"  Kilo, deci, mille are just modifications in latin.  Deci=10 Kilo=1000 Mille=1/1000.  The imperial system is ancient, and based around mankind.  The foot is obvious.  Inch is more or less the distance from the tip of your thumb to the first knuckle.  The mile, also derived from the mille, is 1000 paces.  The problem with those measurements is there is variation from one body to the next.  But once everything is standardized, that no longer matters, it was the closest thing to standardization you could get prior to global communication to really take place.

Randall Carlson was on JRE quite a while ago explaining the history of those measurements and how they relate.  It was some cool shit.  It was around episode 500.  He's a mason and in love with geometry and how things relate.

 

It's just a stick.  I work in SI measurements, I work in fractional inches, I work in decimal inches.  I even work occasionally in fractional meters.  Mathematics, algebra, geometry, and trigonometry only see numbers and doesn't care what derived that number.  US cabinet makers almost solely work in inches.  We don't know what a foot is, or what it would even be used for.  it's never 12' 8-1/2", it's 152-1/2".  Some furniture stuff is still done in whatever the japanese system was, which I know nothing about, but I do know of some people that use that stick for whatever reason.

Science is a different world than what I need measurements for, I work almost solely in length and area, occasionally I need to know volume.

Celsius vs fahrenheit, is a weird one, because science can't agree on units of measure for temperature.  Is zero absolute, or is it when water freezes, or is it something else?  There's still Rankine (sp?), and another one I can't think of.

 

For me base 2,4,8,16 fractions are super easy.  I can do the math in my head most of the time because fractions are easily manipulated.  But if I have a right triangle with equal sides, it's easier to multiply the decimal version of that whatever that number is by the sqrt of 2 on a calculator than it is to do that number/COS(45).  At work, I might build that last formula with all variables so things can be changed with a couple of key strokes and be used for more than a just a triangle with equal legs, so it can be saved and reused for something else other than one part I'm trying to create.

 

Since getting a cnc for work, I really have started to love algebra, geometry, and trig.  Mix those in with parametric software, and you can really do some cool shit when creating programs.  I sucked at all of those in school, because I couldn't relate them to anything.  The answer isn't a goal my brain gives a fuck about, creating a part for something, that is the answer to a problem.  I still have only a basic understanding, I wish I could plug in like the Matrix and learn it all.

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7 hours ago, Rushman said:

Decimal inches... Can anyone explain why these exist?

Stupidity.

A last gasp of avoiding metric.

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Bull Gaytor would tell the girls he was “100 millimeters“ so that it would sound bigger!  

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1 hour ago, warbird said:

It took a country using imperial to be the first to the moon:D

You idiots keep saying that but neglect to point out that it was before the whole world converted to metric.

Well, except for Myanmar, Liberia and America.

Did your grannie never tell you that you're judged by the company you keep?

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29 minutes ago, SloopJonB said:

You idiots keep saying that but neglect to point out that it was before the whole world converted to metric.

Well, except for Myanmar, Liberia and America.

Did your grannie never tell you that you're judged by the company you keep?

But your measurements by then were defined in metric terms, when you were saying 1 inch you were saying 25.4mm because the length of the inch changed in 1959. when they said they flew the 238900 miles to the moon they actually according to the science they all agreed to, they flew 384,400,000 metres. 

The difference being in Imperial terms about 1/8 of an inch per mile.  Or over the distance to the moon an 829.5 ish yard difference.. 

Traditional Land survey yards are 2 parts in a million larger than today's yards.  So today's measurement show the approximate 3000 miles across the USA by land survey is (3000/1000000)*2 or 10.76 yards out... 

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9 hours ago, Streetwise said:

Growing up in America, I learned and used imperial measurements, but also metric for science, track, plus all the different numerical representations for computer science, (my favorite is probably a ratio in Common Lisp), and a few necessary sailing units. Canada was right next door, so we had some other metric training. Later, I learned units for HTML and CSS.

I used to wonder why metric wasn't adopted universally where it was an option.

I was searching to re-read the piece mentioned in this thread.

Here it is, plus some other cool pieces on the topic I found along the way.

http://briontoss.com/index.php/2017/12/11/the-metric-system-pidgin-measurement/

https://maticjelovcan.wordpress.com/2016/05/03/in-defence-of-imperial-system-of-measurement/

https://medium.com/@jamestmarriott/in-defence-of-imperial-measurements-16ebde8ad3a5

I thought it would be cool to discuss this further. I think unit choice is more nuanced than I used to.

Music is also an interesting part of this topic.

Cheers

 

The USA converted to metric decades ago 

:D

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Caltrans converted all its plans, specs, and mapping to metric units back in the 90s. 

Cost mucho millions. Caused much confusion with construction companies, and county recorders offices along with private citizens in regards to legal descriptions in deeds.

Caltrans converted back in the 2000s. Cost mucho millions  . . .

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2 hours ago, Dorado said:

Caltrans converted all its plans, specs, and mapping to metric units back in the 90s. 

Cost mucho millions. Caused much confusion with construction companies, and county recorders offices along with private citizens in regards to legal descriptions in deeds.

Caltrans converted back in the 2000s. Cost mucho millions  . . .

:lol:

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8 hours ago, Hatin' life said:

They use decimal feet don't they?  Along with the Rod, which is 16½ ft out I remember correctly?

That gets confusing if you're not used to it.

Correct. Apologies.

I confused decimal feet with decimal inches.

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6 hours ago, SloopJonB said:

You idiots keep saying that but neglect to point out that it was before the whole world converted to metric.

Well, except for Myanmar, Liberia and America.

Did your grannie never tell you that you're judged by the company you keep?

More of that tribal bullshit mixed with childish name calling.  This time over a stick.

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25 minutes ago, Pipe Dream said:

Correct. Apologies.

I confused decimal feet with decimal inches.

No apology required, I was double checking to see if my memory was correct.

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I once heard a professional woodworker make the argument that Imperial was the better standard of measurement.  His argument was the divisibility of the units.  1, 1/2 ,1/4, 1/8 ,1/16, 1/32, 1/64, etc. 

As someone who has worked in construction and dabbled in woodworking, and used Imperial as the standard unit in that time, I only recently found metric preferable.  The reason is, as my eyesight worsens, the metric rules are easier to read in that "microscopic" realm.

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19 minutes ago, Jules said:

I once heard a professional woodworker make the argument that Imperial was the better standard of measurement.  His argument was the divisibility of the units.  1, 1/2 ,1/4, 1/8 ,1/16, 1/32, 1/64, etc. 

Here's a fun twist, you can do all that with a meter as well.  Even apples.  They can both be divided by 1, .5, .25, .125, .0625, .03125.

I don't know what a sixty fourth is in decimal off the top of my head.  :(

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.015625 apparently.  Needed a calculator though.

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I needed a window shade, but did not have a ruler handy, but there was a piece of string.  I took it to the box store and asked the girl to help me find a shade that as long as the string. 

She said, "You can't do that".

I said, "this is an improvised measuring device".

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7 hours ago, SloopJonB said:

You idiots keep saying that but neglect to point out that it was before the whole world converted to metric.

Well, except for Myanmar, Liberia and America.

Did your grannie never tell you that you're judged by the company you keep?

tThe moon is closer in miles.We only had to go 238000 miles. Everyone else has to go 384000 km:D

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37 minutes ago, Jules said:

I once heard a professional woodworker make the argument that Imperial was the better standard of measurement.  His argument was the divisibility of the units.  1, 1/2 ,1/4, 1/8 ,1/16, 1/32, 1/64, etc. 

Wow, truly incredible! So 6 of the 63 possible fractions are easily divisible. What a huge win!!! 

Quick, what is the body size of a #10 screw? What drill bit for that? What nail is half as long as an 8d nail? Some maybe know this stuff by rote...but what a bunch of brain clutter.

Sticking with a measuring system just to please a bunch of uneducated stick home builders does not seem like a good economic plan. 

 

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41 minutes ago, Hatin' life said:

Here's a fun twist, you can do all that with a meter as well.  Even apples.  They can both be divided by 1, .5, .25, .125, .0625, .03125.

I don't know what a sixty fourth is in decimal off the top of my head.  :(

The argument was that there is a mark on imperial rulers right down to the 64th.  There is no such thing in metric.

9 minutes ago, El Boracho said:

Wow, truly incredible! So 6 of the 63 possible fractions are easily divisible. What a huge win!!! 

Quick, what is the body size of a #10 screw? What drill bit for that? What nail is half as long as an 8d nail? Some maybe know this stuff by rote...but what a bunch of brain clutter.

Sticking with a measuring system just to please a bunch of uneducated stick home builders does not seem like a good economic plan.

Time to take a chill pill.  We aren't talking about how to prevent the end of the world.

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29 minutes ago, El Boracho said:

Sticking with a measuring system just to please a bunch of uneducated stick home builders does not seem like a good economic plan. 

Is this a push for a global currency?

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My Grade 12 class was the first one to complete the sciences in Metric.  I was a metric Nazi and was convinced that the Imperial System would disappear in a few years.

Fast forward 30 to 40 years and my boat speed is measured in knots, the depth alarm is set in feet, the length is most often described in feet and my laptop has a 13 inch screen.

I give up and go with it.

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11 minutes ago, astro said:

My Grade 12 class was the first one to complete the sciences in Metric.  I was a metric Nazi and was convinced that the Imperial System would disappear in a few years.

Fast forward 30 to 40 years and my boat speed is measured in knots, the depth alarm is set in feet, the length is most often described in feet and my laptop has a 13 inch screen.

I give up and go with it.

And you can't convert in your head?

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10 hours ago, warbird said:

It took a country using imperial to be the first to the moon:D

It took a country using Germans using metric to be the first on the moon.

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1 hour ago, Hatin' life said:

Here's a fun twist, you can do all that with a meter as well.  Even apples.  They can both be divided by 1, .5, .25, .125, .0625, .03125.

I don't know what a sixty fourth is in decimal off the top of my head.  :(

Just whip out your Chinese calipers that go from metric, to inches with fractions to inches in decimal as one clicks of a little black button.

https://www.harborfreight.com/6-in-digital-caliper-with-sae-and-metric-fractional-readings-63731.html

 

And while we are asking "Why",   Why do Yanks call studs 2x4s and Aussies call them 4x2s?       :<)

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11 minutes ago, Point Break said:

How many times are we going to do this? <_<

Offissialley or shoude we incluude unoffissionalley to?

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12 minutes ago, Foreverslow said:

Just whip out your Chinese calipers that go from metric, to inches with fractions to inches in decimal as one clicks of a little black button.

https://www.harborfreight.com/6-in-digital-caliper-with-sae-and-metric-fractional-readings-63731.html

 

And while we are asking "Why",   Why do Yanks call studs 2x4s and Aussies call them 4x2s?       :<)

Especially since they’re 1.5” x 3.5”!

 

Did you hear about the Lesbians that built a house?  They didn’t use any Studs, it was all tongue and groove!  

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3 minutes ago, Foreverslow said:

Just whip out your Chinese calipers that go from metric, to inches with fractions to inches in decimal as one clicks of a little black button.

https://www.harborfreight.com/6-in-digital-caliper-with-sae-and-metric-fractional-readings-63731.html

 

And while we are asking "Why",   Why do Yanks call studs 2x4s and Aussies call them 4x2s?       :<)

You meant calculator I think. One divided by sixty four is tricky to do on a caliper in Si or imperial.  Or I'm not following how to convert 1/64th of an apple into metric.

 

Australia is a unique place.

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2 minutes ago, Point Break said:

How many times are we going to do this? <_<

Chicago to LA is about 2000 miles, in km it's way more:lol:

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36 minutes ago, Foreverslow said:

And while we are asking "Why",   Why do Yanks call studs 2x4s and Aussies call them 4x2s?       :<)

That’s easy... we Aussies are down under so everything is backward to you

Of course we refer to them as 90 x 45s, metric you know

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I'm calling bullshit on this entire thread.

Two-by-fours are actually 1 9/16 x 3 9/16. Don't get me started . . . <_<

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1 hour ago, warbird said:

Chicago to LA is about 2000 miles, in km it's way more:lol:

But we get to drive 120 legally on the highway.

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And then there's the venerable RCH unit of measurement.

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9 minutes ago, SloopJonB said:

But we get to drive 120 legally on the highway.

Oh please! How gauche! 33 m • s⁻¹

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22 hours ago, Rushman said:

Decimal inches... Can anyone explain why these exist?

They're dead nuts money when you're calibrating a folding machine. You have to stay imperial because the paper sizes in the USA are letter, legal, tabloid. 14x20, 28x40, etc.. But when you calibrate the equipment, 16ths, 32nds and 64ths are often not good enough, and using 128ths is a lesson in torture, so we use 100ths and 1000ths of an inch. We use these in many areas of manufacturing and machining.

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5 hours ago, warbird said:

Chicago to LA is about 2000 miles, in km it's way more:lol:

Chicago to LA is about 2000 smiles. 

Or if you try to drive it in metric, it will KILLometer you to the tune of 3200 or so.

I think that smiles are more fun. We got the better system. 

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7 hours ago, El Boracho said:

 

Sticking with a measuring system just to please a bunch of uneducated stick home builders does not seem like a good economic plan. 

Maybe not, but it's a good plan if you don't want the roof to fall onto your head.

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Now what was that joint US-Euro mission to Mars or something about ten years ago...?  Propulsion probably by the US, with the lander by the Euros.  Naturally each group using their own system of measurement.  And it all went swimmingly.  Until someone forgot to translate the units for the lander.  Lost.  Ouch. :o

A very good reason to not co-operate or try to understand each other!  :P

 

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13 hours ago, BravoBravo said:

The USA converted to metric decades ago 

:D

Of course. In fact the standard meter is made possible by an atomic clock that lives down the street from my house at the National Institutes of Standards and Technology.

And funny enough, all of the metric stuff, from GPS satellites in orbit, bolts in a Japanese engine, or a Russian printing press, radio frequencies around the world, they're all based on a clock that measures the passage of time in not Base-Ten metric, but Base-Twelve!

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6 hours ago, Point Break said:

How many times are we going to do this? <_<

What unit do you want the answer in?

22 minutes ago, mikewof said:

Chicago to LA is about 2000 smiles. 

Or if you try to drive it in metric, it will KILLometer you to the tune of 3200 or so.

I think that smiles are more fun. We got the better system. 

Nah. You can go faster in metric so that’s more fun. 3/8 more fun to be precise.

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1 hour ago, Black Sox said:

What unit do you want the answer in?

Nah. You can go faster in metric so that’s more fun. 3/8 more fun to be precise.

Miles are subtle. Do you know why a mile (5280 feet) is equal to 12 x 11 x 10 x 4?

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2 hours ago, Poodle56 said:

Now what was that joint US-Euro mission to Mars or something about ten years ago...?  Propulsion probably by the US, with the lander by the Euros.  Naturally each group using their own system of measurement.  And it all went swimmingly.  Until someone forgot to translate the units for the lander.  Lost.  Ouch. :o

A very good reason to not co-operate or try to understand each other!  :P

 

I think it wasn't a joint mission, just a bit of software from one of the NASA contractors that output data in pounds-feet rather than kilograms-meters.

Meh, shit happens. we need to know to look out for things like that.

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When we get stuff in for calibration, the first thing is to check whether it's set up for 120V or 240V.. Every so often someone will forget....

Then it's check to see what units, it is set up for particularly if it's a Temperature  meter, F, C or K. ( then set it to Metric, return it to what ever the customer uses after calibration.)

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11 minutes ago, mikewof said:

I think it wasn't a joint mission, just a bit of software from one of the NASA contractors that output data in pounds-feet rather than kilograms-meters.

Meh, shit happens. we need to know to look out for things like that.

Probably kips & slugs going into deci-newtons! :lol:

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I always use silly meters when building stuff 

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19 hours ago, The Q said:

But your measurements by then were defined in metric terms, when you were saying 1 inch you were saying 25.4mm because the length of the inch changed in 1959. when they said they flew the 238900 miles to the moon they actually according to the science they all agreed to, they flew 384,400,000 metres. 

The difference being in Imperial terms about 1/8 of an inch per mile.  Or over the distance to the moon an 829.5 ish yard difference.. 

Traditional Land survey yards are 2 parts in a million larger than today's yards.  So today's measurement show the approximate 3000 miles across the USA by land survey is (3000/1000000)*2 or 10.76 yards out... 

And during the Apollo missions the distances to and from the moon were given in nautical miles.

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3 hours ago, mikewof said:

Miles are subtle. Do you know why a mile (5280 feet) is equal to 12 x 11 x 10 x 4?

No, but I would love to know...

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20 hours ago, The Q said:

The difference being in Imperial terms about 1/8 of an inch per mile.  Or over the distance to the moon an 829.5 ish yard difference.. 

What do you mean by this?  An inch is *exactly* 2.54 cm.  If you go 250,000 mi, it's 15.840x10^9 inches or 40.2336x10^9 cm.  It's just a conversion.  You might lose things in significant figures, but that's what error bars are for.

 

1 mile = 5280 feet = 63,360 in = 160,934.4 cm.  Where are you losing an 1/8th of an inch?  In the decimal place?  That's what the decimal place is for.

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17 hours ago, bplipschitz said:

What do you mean by this?  An inch is *exactly* 2.54 cm.  If you go 250,000 mi, it's 15.840x10^9 inches or 40.2336x10^9 cm.  It's just a conversion.  You might lose things in significant figures, but that's what error bars are for.

 

1 mile = 5280 feet = 63,360 in = 160,934.4 cm.  Where are you losing an 1/8th of an inch?  In the decimal place?  That's what the decimal place is for.

The difference between the old Pre 1959 Inch and the post 1959 inch. An inch only became exactly 25.4mm in 1959.

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working in chemistry is so much easier in metric than imperial

 

weights, volumes, sg and measurements

 

1 ltr of water = 1 kg  ie an sg of 1

do that with pounds per gallon

 

all the cnc machines i programmed ( mostly strippet ) had an accuracy of .1 mm easy to work out the drawings and programs with that

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On 8/9/2020 at 6:53 PM, Rushman said:

Decimal inches... Can anyone explain why these exist?

Because machine tools were calibrated in thousandths of an inch.

Nowadays hopefully you have a DRO and just push the button to your desired units and backlash et al is a thing of the past.

Hopefully...

FKT

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6 hours ago, Fah Kiew Tu said:

Because machine tools were calibrated in thousandths of an inch.

Nowadays hopefully you have a DRO and just push the button to your desired units and backlash et al is a thing of the past.

Hopefully...

FKT

Quantization error is the new backlash.

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I'm pleased to note a small bit of progress at work.   The thermometer came in designed with C as default.  F required three keystrokes per use.   I placed the state mandated maximum temp of 38C on a sticker, the logbook shows all employee temps is in C.   There is no minimum temp required.  :wacko:

Also an observation for home projects.  Many products are built to a cm whole number, including picture frame's hanger placement.   A metric tape measure makes hanging, mounting or arranging these products much easier.   I noticed this hanging a series of 8*10 " photos in a pattern of alternating vertical and horizontal, the hook distance to the end of the frame was in cm.    Likewise the drill distance for a bracket with multiple holes is usually in metric, even if the bracket is for an imperial sized shelf.  

 

 

 

 

 

 

 

 

  

 

 

 

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7 hours ago, IStream said:

Quantization error is the new backlash.

Yeah but dithering over a micron plus/minus is OK as far as I'm concerned. Got to be running everything in a temperature controlled environment for it to really matter.

FKT

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15 hours ago, phill_nz said:

working in chemistry is so much easier in metric than imperial

 

weights, volumes, sg and measurements

 

1 ltr of water = 1 kg  ie an sg of 1

do that with pounds per gallon

 

all the cnc machines i programmed ( mostly strippet ) had an accuracy of .1 mm easy to work out the drawings and programs with that

All you really need to know is "A pint's a pound the world around.", everything else is easy after that:D

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12 minutes ago, warbird said:

All you really need to know is "A pint's a pound the world around.", everything else is easy after that:D

"A pint's 1.043125 pound the world around." B)

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On 8/10/2020 at 12:50 AM, warbird said:

It took a country using imperial to be the first to the moon:D

Quote

 

NASA has ostensibly used the metric system since about 1990, the statement said, but English units are still employed on some missions, and a few projects use both. NASA uses both English and metric aboard the International Space Station.

The dual strategy led to the loss of the Mars Climate Orbiter robotic probe in 1999; a contractor provided thruster firing data in English units while NASA was calculating in metric.

 

https://www.space.com/3332-nasa-finally-metric.html#:~:text=NASA has ostensibly used the,aboard the International Space Station.

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15 hours ago, phill_nz said:

All the cnc machines i programmed ( mostly strippet ) had an accuracy of .1 mm easy to work out the drawings and programs with that

I think that used to be pretty typical.

 

The software I draw cabinets in and post parts to the cnc from has only a granularity of .1 mm.  Drives me fucking nuts when I want my tool to only penetrate the the reference face by .002" and it calls it zero.  I cheat the Z zero to get what I want, but that fucks with every operation that isn't all the way through.

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54 minutes ago, El Boracho said:

"A pint's 1.043125 pound the world around." B)

Also, 1.000028 ltr of pure water at 277.15K and 1013.25hPa (aka millibars) is a pretty good approximation of a kg.

 

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2 hours ago, warbird said:

All you really need to know is "A pint's a pound the world around.", everything else is easy after that

ohh well

you keep making stuff in imperial

and the rest of the world will continue not buying them

ever since JIT came in

no accountant will let purchasing buy an imperial machine because they instantly have to buy a complete set of imperial tools and spares

 

calculators love scaling formulations in metric

imperial .. not so much

 

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On 8/9/2020 at 9:23 AM, Hatin' life said:

Ever do any machining?

I wood work with decimal inches! And I also happen to be a prototype machinist so I breathe decimal inch.

.001” is a wonderful increment of measuring. How much clearance do you think this shaft to bushing needs?

Maybe 3 or 4 thousands,  yea sounds about right. 
 

Or maybe .07 to .01 mm, tough to think of that as an equivalent to a thick piece of paper.  I cannot get a feel for hundredths of a millimeter. 
 

I speak both languages, I prefer decimal inch when doing any fine measurement. 

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On 8/11/2020 at 2:22 AM, The Q said:

The difference between the old Pre 1959 Inch and the post 1959 inch. An inch only became exactly 25.4mm in 1959.

Thanks to the Canadians!

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34 minutes ago, phill_nz said:

ohh well

you keep making stuff in imperial

and the rest of the world will continue not buying them

ever since JIT came in

no accountant will let purchasing buy an imperial machine because they instantly have to buy a complete set of imperial tools and spares

 

calculators love scaling formulations in metric

imperial .. not so much

 

I am sorry you do not catch the innate wisdom and tongue in cheek humor.

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9 minutes ago, warbird said:

I am sorry you do not catch the innate wisdom and tongue in cheek humor.

 

well its from you .. so if true its a natural blind side

 

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4 hours ago, heavym210 said:

I speak both languages, I prefer decimal inch when doing any fine measurement. 

microns are my choice

all systems are easy when you are used to them

standardization across the planet makes sense

 

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13 hours ago, warbird said:

All you really need to know is "A pint's a pound the world around.", everything else is easy after that:D

 

10 hours ago, warbird said:

I am sorry you do not catch the innate wisdom and tongue in cheek humor.

 

10 hours ago, phill_nz said:

 

well its from you .. so if true its a natural blind side

 

Rough mental maths , a little better than WAGs, give you fluid 16oz/ ~1 ltr =~ 1 lb, 1 gal/~4 ltr =~8 lb.  Add ~10% to the ltr weight if better precision is needed in mental maths. When you are rough calculating your fuel tank weight near the stern of your boat or a bow water tank or a holding tank you can get a pretty good idea of how important it is to race with them nearly empty..B)

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11 hours ago, heavym210 said:

I speak both languages, I prefer decimal inch when doing any fine measurement. 

Yeah, I have no problem with using both metric and imperial tools, of machining in thousandth of an inch while calculating the actual physics of the device in meters-seconds-kilograms.

But for some reason, the thought of us Yanks using both systems seems to drive Europeans insane, they insist on standardization of measurement for us, even while using two or three languages.

And then they make jokes about us not being bilingual.

Oddly, in printing, most of the world still uses points and picas, which are inch-based, or at least are supposed to be inch-based. I send my Galaxy Gauge tools all over the world, and printers and designers still prefer the old points and picas.

That standard is supposed to be 6 picas to the inch, it was originally invented in France back in the 1800s. But when France went with System Internationale units, they just locked the pica into place,, since the inch standard disappeared.

That's when things started to unravel. Printers all over the world used a liter pica pole as the length standard, and eventually forgot about its connection to the inch. The pica became 6.02 picas to the inch.

It worked well enough until the 1990s, when imagesetters from Linotype didn't have the computing horsepower for that 6.02 value, they just used 6 picas, as is correct. And the desktop publishing software from Quark could be set to either 6 or 6.02.

Absolute chaos ensued. Jobs wouldn't fold right, the strippers and finishing folks used their trusty 6.02 pica poles, while the computer folks used 6. It was common in the 1990s to see bins completely filled with fucked up print jobs. Tens of millions of dollars of print waste was common.

I standardized my Galaxy Gauge tools to the correct 6 pica custard standard, but Schaedler, C-Thru and some others stuck to 6.02, or just offered one of each.

I remember consulting with a printer in Sydney who was convinced that his employees were deliberately sabotaging his business. The 0.02 difference was too subtle to pick up until the jobs went into finishing.

Now, nobody uses the 6.02 standard unless they screw up, but for a decade, it was a real mess.

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8 hours ago, phill_nz said:

microns are my choice

all systems are easy when you are used to them

standardization across the planet makes sense

Microns are specifically discouraged by some manufacturers, because "microns" refers to an earlier steel grain standard.

It's micrometers and nanometers, specifically when the length standard is determined by laser light (i.e. most contemporary equipment) and "microns" for legacy equipment defined by the steel mesh.

It's a helpful method, because the EPA publishes micron measurements that are based on the old mesh particle gauges and micrometers (or more commonly the Latin mu-meters) for the laser interferometry standards.

Another change is that some manufacturers don't want their employeess to publish in Angstroms, because they sometimes get swapped out for nanometers and then introduce an order of magnitude error. I miss Angstroms though, I almost never see them anymore. The shorthand was the best ... Å

One thing we need to shitcan is Celsius and Centigrade, they're just as silly as Fahrenheit, but without as much resolution, and that ridiculous zero point is still there. Kelvin is a functional choice.

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23 minutes ago, mikewof said:

Kelvin is a functional choice.

How about Rankine?  Finer divisions.

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