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METRIC ! 52
- Thread starter ceesjan
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I design in english units because I have a feel for them. My co-worker from Germany converts my answers to metric, so he can understand them. I convert his answers to english units. We create our drawings in metric units. The machinist on the shop floor recalculates the dimensions on the drawing to inches because his measuring devices are in inches.
I guess we will all be metric when time is measured in units of 10.
I guess we will all be metric when time is measured in units of 10.
This is a very interesting discusion, and I particularly like butelja's take on the matter, though that may only be becuse I am half drunk.
I am a Canadian electrician, who is having a bit of an identity crisis. The code book I follow is slowly converting to metric; the most recent version gives all dimensions in metric, followed by imperial in brackets for those of us who still think in inches. eg 1000mm (36"
. It isn't an exact science . When I order wire from the wholesaler, it's in meters. When I figure how much wire I've used on a service call it's in feet. The project I'm currently on gives the arcitectural dimensions in metric, and the electrical engineer has mostly followed suit, but not always. So, I have a light that is centered between two doorways, 2600mm apart, and 9'8" off the ground.
I'm not sure if there is any point to this story, but it should show that with a bilingual tape measure I am pertectly comfortable working in any unit people throw at me, and I don't think twice about it.
If people can fluently speak more than one language, why shouldn't they do the same with numbers?
I am a Canadian electrician, who is having a bit of an identity crisis. The code book I follow is slowly converting to metric; the most recent version gives all dimensions in metric, followed by imperial in brackets for those of us who still think in inches. eg 1000mm (36"
. It isn't an exact science . When I order wire from the wholesaler, it's in meters. When I figure how much wire I've used on a service call it's in feet. The project I'm currently on gives the arcitectural dimensions in metric, and the electrical engineer has mostly followed suit, but not always. So, I have a light that is centered between two doorways, 2600mm apart, and 9'8" off the ground.I'm not sure if there is any point to this story, but it should show that with a bilingual tape measure I am pertectly comfortable working in any unit people throw at me, and I don't think twice about it.
If people can fluently speak more than one language, why shouldn't they do the same with numbers?
Of course there is the issue of safety also. People are less likely to make mistakes when they are 'singing from the same hymn sheet'.
I'ver heard a few horror stories such as a ground crew putting the wrong amount of fuel on a people carrier because they mistook metric with imperial.
Speedy
I'ver heard a few horror stories such as a ground crew putting the wrong amount of fuel on a people carrier because they mistook metric with imperial.
Speedy
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My reasons for universal use of SI units:
1) pound-mass/pound-force is the worst abomination ever used in an engineering field.
2) kilogram mass can be directly linked to the periodic table and atomic masses.
3) the link between electromagnetism and mechanics - how would one use inches and pounds with volts, amps, etc.?
1) pound-mass/pound-force is the worst abomination ever used in an engineering field.
2) kilogram mass can be directly linked to the periodic table and atomic masses.
3) the link between electromagnetism and mechanics - how would one use inches and pounds with volts, amps, etc.?
In an earlier post, I mentioned the loss of a NASA space probe (turns out it was worth $125 million). For more information on that disaster, and many of the interesting newspaper articles that ensued, try going to
Interstingly, many of these articles blast the U.S. for not converting to metric. In the same article, they blast the NASA and Lockheed engineers for making such a stupid mistake (i.e., not converting into one system or the other). In my mind, that mistake is much more stupid than the US refusing to switch to metric. Another interesting site defends the US's use of the English system:
Enjoy,
Haf
Interstingly, many of these articles blast the U.S. for not converting to metric. In the same article, they blast the NASA and Lockheed engineers for making such a stupid mistake (i.e., not converting into one system or the other). In my mind, that mistake is much more stupid than the US refusing to switch to metric. Another interesting site defends the US's use of the English system:
Enjoy,
Haf
Engineers are, axiomatically and at least: closet-trekkies ... therefore we all know where we going regarding measuring systems.
Live long and prosper!
\\//
[_]=
(This pretended to be the Vulcan greeting).
Now, the amount of information that has to change (specially road signs, maps, scales, etc...) is so humongous that nobody is willing to accept the cost.
Also, the US version of the imperial units is called Std. e.g. the imperial gallon is different from the US gallon...why this does not surprise us?
o-) (smiling cyclop)
Live long and prosper!
\\//
[_]=
(This pretended to be the Vulcan greeting).
Now, the amount of information that has to change (specially road signs, maps, scales, etc...) is so humongous that nobody is willing to accept the cost.
Also, the US version of the imperial units is called Std. e.g. the imperial gallon is different from the US gallon...why this does not surprise us?
o-) (smiling cyclop)
Beware the non-standardization even within an existing system.![[curse]](/data/assets/smilies/curse.gif "[curse] [curse]")
I once encountered difficulties with installing new, fabricated in place, brake lines on a vehicle that I was restoring. It seems the number of threads per millimeter on the vehicle (German) were different from the number on the tool used for the lines (english) even though both were fine pitch threads! Not wanting to subject myself to leaking brake lines, I had to search out the correct components for connecting the lines to the vehicle.
I once encountered difficulties with installing new, fabricated in place, brake lines on a vehicle that I was restoring. It seems the number of threads per millimeter on the vehicle (German) were different from the number on the tool used for the lines (english) even though both were fine pitch threads! Not wanting to subject myself to leaking brake lines, I had to search out the correct components for connecting the lines to the vehicle.
dougholmes
Mechanical
When I read the story of the NASA space probe being mis-directed, it sounded like one company was giving data about the characteristics of the equipment they supplied (a thruster, I believe). Another organization was using that data to compute how long the thrusters were to be operated to tweak the course as the craft made its way out to the target plant. By the time the craft was near the planet the course was too far off for the limited power in the thrusters to correct the course.
The "how much thrust does this device generate" was given as a number with no units of measure attached. (like: thrust=27)
The other group seems to have assumed that the unit of measure was metric but in reality, it was English or Imperial or US or whatever name is most popular at the time.
The problem is that a number without units of measure attached means nothing. It has no meaning in the world of physical objects or phenomena. So the REAL problem was not that one party was using one system of measurement and the other was using another system, but that the first group supplied a number without a unit of measure and the second group didn't DEMAND that the unit of measure be supplied. They just assumed something.
Some time ago, the owner of a company I worked for had this little saying.
"Don't assume anything, ..."
(and at this point he would have already written ASSUME on the chalk-board)
" ... because when you do ... "
(then he drew slashes on both sides of the "U" in the word - ASS/U/ME)
" ... you make an ASS out of U and of ME!"
The "how much thrust does this device generate" was given as a number with no units of measure attached. (like: thrust=27)
The other group seems to have assumed that the unit of measure was metric but in reality, it was English or Imperial or US or whatever name is most popular at the time.
The problem is that a number without units of measure attached means nothing. It has no meaning in the world of physical objects or phenomena. So the REAL problem was not that one party was using one system of measurement and the other was using another system, but that the first group supplied a number without a unit of measure and the second group didn't DEMAND that the unit of measure be supplied. They just assumed something.
Some time ago, the owner of a company I worked for had this little saying.
"Don't assume anything, ..."
(and at this point he would have already written ASSUME on the chalk-board)
" ... because when you do ... "
(then he drew slashes on both sides of the "U" in the word - ASS/U/ME)
" ... you make an ASS out of U and of ME!"
Well here in the UK you can see some beautiful drawings designed to confuse, i have seen many drawings marked in both Metric and imperial, now thats confusing.
When i was at school, i was taught only metric measurements,because we were told that the whole world worked in metric and we had to learn the new standard, and when i left to start an apprentiship you could see in the training centre about 100 faces in total blankness as the training officer spoke about inches and 3/18ths. So it just goes to show that what academia want and what industry gives are two different poles.
When i was at school, i was taught only metric measurements,because we were told that the whole world worked in metric and we had to learn the new standard, and when i left to start an apprentiship you could see in the training centre about 100 faces in total blankness as the training officer spoke about inches and 3/18ths. So it just goes to show that what academia want and what industry gives are two different poles.
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My car runs 53 stonethrows a mug diesel.
We must accept that engineering is a multi-cultural environment.
It's just like understanding different languages.
I hope that we are all smart, reasonable and patient PEOPLE (!) here. And that we can easily deal with it.
- peace, Doryan
We must accept that engineering is a multi-cultural environment.
It's just like understanding different languages.
I hope that we are all smart, reasonable and patient PEOPLE (!) here. And that we can easily deal with it.
- peace, Doryan
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- #34
I do hope some-one buries a copy of this thread in a time capsule somewhere. It should be good for some raucous laughter in about 50 year's time. Mind you, the designers/builders of the Tower of Babel have a lot to answer for in establishing so many different systems of units around the globe.
There are some beautifully fallaceous arguments for maintaining a status quo to be found in this one thread.
eg "the amount of information that has to be changed is humungous...that nobody is willing to accept the cost". But some countries have accepted the cost.
Having made the conversion, it didn't seem any big deal in Australia (where, surprisingly we do have road signs and maps etc). Granted, pipe fittings and the like largely remain non-metric, but they are not generally nicely 'imperial' anyway (other than threads/inch, how many of the thread dimensions are good looking numbers in either inches or mm?) Similarly wire gauges, which have always been a total mystery to me anyway.
Personally I find dynamic calculations very much simpler in the SI system. All I need to bear in mind is the definition of a Newton force (the force which accelerates a mass of 1 kg by 1 m/sec^2), and all is clear. No more having to remember the nicety of pounds, poundals, slugs, the gravitational constant or whatever.
I, like many others of my age, went through a period of wondering what on earth my design calculations in SI units really meant, and whether the results were reasonable. (When I first read 'Newton' in technical papers, I was inclined to believe that it referred to a New ton - yet another sort of ton, to go with the long, short and metric tons !). But that passed quite quickly, and I would hate to have to return to imperial units again.
And for those who hanker for 'human derived units' - what would be more 'human' than to name the SI force unit after the 'inventor' of gravity, and make it equal to the weight of a British Standard Apple? (About 10 to the kilogram, 4.5 to the pound)
There are some beautifully fallaceous arguments for maintaining a status quo to be found in this one thread.
eg "the amount of information that has to be changed is humungous...that nobody is willing to accept the cost". But some countries have accepted the cost.
Having made the conversion, it didn't seem any big deal in Australia (where, surprisingly we do have road signs and maps etc). Granted, pipe fittings and the like largely remain non-metric, but they are not generally nicely 'imperial' anyway (other than threads/inch, how many of the thread dimensions are good looking numbers in either inches or mm?) Similarly wire gauges, which have always been a total mystery to me anyway.
Personally I find dynamic calculations very much simpler in the SI system. All I need to bear in mind is the definition of a Newton force (the force which accelerates a mass of 1 kg by 1 m/sec^2), and all is clear. No more having to remember the nicety of pounds, poundals, slugs, the gravitational constant or whatever.
I, like many others of my age, went through a period of wondering what on earth my design calculations in SI units really meant, and whether the results were reasonable. (When I first read 'Newton' in technical papers, I was inclined to believe that it referred to a New ton - yet another sort of ton, to go with the long, short and metric tons !). But that passed quite quickly, and I would hate to have to return to imperial units again.
And for those who hanker for 'human derived units' - what would be more 'human' than to name the SI force unit after the 'inventor' of gravity, and make it equal to the weight of a British Standard Apple? (About 10 to the kilogram, 4.5 to the pound)
Cheers Austim!
That was brilliantly put. I liked, particularly, the time capsule thing. Indeed time unit is invariant![[wink]](/data/assets/smilies/wink.gif "[wink] [wink]")
to any system of units (although I know some units other than hours, minutes and seconds but they are not in vogue now).
But are you soothsaying common units in coming 50 years?![[noevil]](/data/assets/smilies/noevil.gif "[noevil] [noevil]")
I totally agree with your point on threads and wire gauge.
But disagree with 'invention' of gravity, for before that too, people never used to fall down(?) on earth(oh no! can't exactly make my point)
Anyhow I vote for SI units.
I wish you a happy retirement life. (I read it in one of your other (great) posts)
Regards,
Repetition is the foundation of technology
That was brilliantly put. I liked, particularly, the time capsule thing. Indeed time unit is invariant
to any system of units (although I know some units other than hours, minutes and seconds but they are not in vogue now).But are you soothsaying common units in coming 50 years?
I totally agree with your point on threads and wire gauge.
But disagree with 'invention' of gravity, for before that too, people never used to fall down(?) on earth(oh no! can't exactly make my point)
Anyhow I vote for SI units.
I wish you a happy retirement life. (I read it in one of your other (great) posts)
Regards,
Repetition is the foundation of technology
It must be a difficult issue when going down to details because some products are design and developed in US and manufactured over seas.
The jobs done in US have to go for english units because most vendors are in this systems.
But the production over-seas usually use ISO systems. The exchanges between two systems sometimes causes terrible problems not only in accuracy but in parts supplies.
Currently, we are using dual-dimension systems.
Sooner or later, we have to face the globle-village situation. For now, it is just in transition between.
The jobs done in US have to go for english units because most vendors are in this systems.
But the production over-seas usually use ISO systems. The exchanges between two systems sometimes causes terrible problems not only in accuracy but in parts supplies.
Currently, we are using dual-dimension systems.
Sooner or later, we have to face the globle-village situation. For now, it is just in transition between.
WOW, I have enjoyed reading this thread and wish to add my bit to the time capsule. As a teacher of engineering to entry level students, apprentices and Diploma students for 15 years I can vouch for the simpler metric system. A 10 base is easier for students to follow, with a system of prefix's and by the use of engineering notations (+ve and -ve) and keeping their answers to within 1 and 1000 also makes for nice looking figures.
We still mention imperial however, here in Australia, because many countries still supply machinery and equipment to this standard. The generation gap in some workshops still hear the older tradesman telling the apprentice to make it a few thou(imperial)over the 25mm size to allow for a press fit.
The duoppoly of systems has lead to catastrophic outcomes and surely it is about time the engineering industry united to say "Metrics the Way - nothing else from this day!"![[2thumbsup]](/data/assets/smilies/2thumbsup.gif "[2thumbsup] [2thumbsup]")
Let's say, Jan 1, 2010 to give us fair warning!
We still mention imperial however, here in Australia, because many countries still supply machinery and equipment to this standard. The generation gap in some workshops still hear the older tradesman telling the apprentice to make it a few thou(imperial)over the 25mm size to allow for a press fit.
The duoppoly of systems has lead to catastrophic outcomes and surely it is about time the engineering industry united to say "Metrics the Way - nothing else from this day!"
Let's say, Jan 1, 2010 to give us fair warning!
It would be a great service to the World if some person or agency could convince us all use the same unit system. It will likely happen a few centuries after world government is established.
My doctor said I should take a thousand milligrams of vitamin C per day. I said isn't that the same as a gram? He wasn't sure.
My doctor said I should take a thousand milligrams of vitamin C per day. I said isn't that the same as a gram? He wasn't sure.
I'll throw in two good stories about units problems--
While travelling from Michigan to New York (which all Michiganders know takes one through Canada), we left the
US at 28 degrees. As we switched to listen to a Canadian radio station, my wife remarked how much colder it had apparently gotten in the last few hours, as the temperature had plummeted to -2. (She figured out her mistake when I about lost control of the car laughing).
While working at Opel, I was on the Proving Ground and a German engineer showed me a paved ramp (often proving grounds have ramps at various angles for a variety of tests). The ramp was clearly not in use. He explained to me that they got the spec's from the US and diligently converted the length of the overall ramp from meters to units. Somebody overlooked converting the height (from inches/ft rise/run), and ended up building the ramp in inches/meter (thinking it was cm/meter). After the meticulous construction was done, their slope was off by 1/2.54. They decided to leave it that way as a cautionary tale . . .
Brad
While travelling from Michigan to New York (which all Michiganders know takes one through Canada), we left the
US at 28 degrees. As we switched to listen to a Canadian radio station, my wife remarked how much colder it had apparently gotten in the last few hours, as the temperature had plummeted to -2. (She figured out her mistake when I about lost control of the car laughing).
While working at Opel, I was on the Proving Ground and a German engineer showed me a paved ramp (often proving grounds have ramps at various angles for a variety of tests). The ramp was clearly not in use. He explained to me that they got the spec's from the US and diligently converted the length of the overall ramp from meters to units. Somebody overlooked converting the height (from inches/ft rise/run), and ended up building the ramp in inches/meter (thinking it was cm/meter). After the meticulous construction was done, their slope was off by 1/2.54. They decided to leave it that way as a cautionary tale . . .
Brad
I'll through my 2 cents worth in on this one too.
If I'm not mistaken the US government offically adopted the metric system over 100 years ago. Its the US businesses that are dragging their feet. Most of us here would be willing to accept the change, except for the cost. I personally prefer working with base 10, the math is much easier. Eventually we will all be working with the same set of numbers, but that will probably take another 50 to 100 years.
Now for the funny stuff, My wifes Toyota has a standard oil drain plug, My Chevrolet has a metric oil drain plug so does my Ford. The Toyota was built in the US, the Chevrolet in Canada, and the Ford in Mexico.
The 'cup' of coffee I bought on the way to work this morning held 24 ounces, thought it also could have held 12, 16 or 20 ounces also.
If I'm not mistaken the US government offically adopted the metric system over 100 years ago. Its the US businesses that are dragging their feet. Most of us here would be willing to accept the change, except for the cost. I personally prefer working with base 10, the math is much easier. Eventually we will all be working with the same set of numbers, but that will probably take another 50 to 100 years.
Now for the funny stuff, My wifes Toyota has a standard oil drain plug, My Chevrolet has a metric oil drain plug so does my Ford. The Toyota was built in the US, the Chevrolet in Canada, and the Ford in Mexico.
The 'cup' of coffee I bought on the way to work this morning held 24 ounces, thought it also could have held 12, 16 or 20 ounces also.
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