In science, imperial units are very rarely used. Acceleration due to gravity? ~9.81 m/s^2. The speed of light? 3 x 10^8 m/s. Speed of sound? 343 m/s at sea level. The wavelength of red? 650 nm.
When it comes to linear measurements, meters are very easy to work with.
1000 meters in a kilometer, 100 centimeters in a meter, 10 millimeters in a centimeter, 1,000,000 nanometers in a millimeter.
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In imperial units, there are 5280 feet to a mile, 12 inches to a foot, and many different ways of breaking up an inch. There are (8) 8ths, (16) 16ths, (32) 32nds, (64) 64ths, or (1000) mils(mils are NOT millimeters) in an inch.
And with volume measurements, milliliters and liters can be less confusing than dealing with teaspoons, tablespoons, cups, pints, quarts, and gallons.
The simplicity of the metric system carries over into material dimensions, fastener sizes, and tooling, yet I am so comfortable with inch and imperial units that it will be difficult for me to fully adapt the metric system without compulsion.
Then there are temperature measurements. Despite working with celsius and centigrade on paper, my body understands fahrenheit a lot better.
I bought a dual inch/metric tape measure a few years ago, and try to use whichever one is more convenient on a case-by-case basis. You know what? Sometimes I find inch units to be easier to use.
Way back when I first learned metric units in class somewhere, we were told that eventually the USA would probably move to the metric system. Now, maybe 20 years later, that still hasn’t happened.
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I am okay using metric units on paper, but in real life, I’m not quite as comfortable with them as I probably should be. If forced to fully adopt the metric system, I would probably get used to more quickly and easier than others who haven’t used it as much, but it wouldn’t be an instant process.
Metric measurements are common on consumer goods, such as food and beverages, as well as personal items, so maybe – eventually – the transition won’t be as painful as a lot of people fear.
Right now, according to the CIA, the United States is joined by Burma and Liberia as the only 3 countries in the entire world that have not adopted the metric system as the their official system of weights and measures.
Eventually, we’re bound to see an involuntary switchover, but it will take a lot of convincing for that to happen. Somewhere in the past few decades, the metrification effort lost out to an if it ain’t broke, don’t fix it attitude, and it will take a big push to undo this.
For anyone else that typically works with inches, feet, Fahrenheit, and ounces, are you ever eager to use the metric system instead? Or do you fiercely resist any more exposure to metric units than you must work with?
Jerry
Working on metric fasteners on my ATV has gotten me to the point I can recognize some of the sizes, like I can with inch fasteners (do I need a 1/2 or 9/16). However, there is one big hurdle (for me) when it comes to fuly accepting the metric system. I am a wrench turner, and am used to coarse or fine threads, as well as a standard wrench size for a certain bolt size. The metric system has, in my experience, at least 3 thread pitches for each bolt size, and while their head size does bear some relation to the boot size, it is not standardized. Many is the time I needed a bolt, and grabbed the wrong size because I assumed the head size would determine the bolt size, and don’t even get me started on the bolts that thread in about 7/8 of a turn, and start to get tough, because the thread pitch wasn’t the same.
Personally, if they could sort out a standard head size, and settle on just a coarse or fine thread, I think I could adapt to the rest of the metric system fairly seamlessly, except maybe for not knowing how to dress when it was 40 degrees out.
Stuart
To be fair, SAE fasteners have this issue too. The other day I cross-threaded a T-nut after confusing #10-24 and #10-32 socket cap screws.
RX9
Concerning thread pitch, most metric fasteners size M7 and smaller have only one pitch. A few have two or more, but usually the coarse one is used.
The worst offenders are M10 and M12, with three pitches each.
The “very fine” pitches are rather rare.
I’ve noticed that M10 x 1.25 shows up more in Japanese cars, while M10 X 1.5 is more prevalent in domestics.
fred
Being an Old guy and having a passion for working on even older bicycles and cars, I’ve encountered a batch of fasteners that sometimes meet today’s metric standards (e.g. ISO fine and coarse) but also other standards like Old Metric (e.g. 2 x 0.25 and 9 x 1), Löwenherz (e.g. 3.5 x 0.6 and 4.5 x 0.75), JIS (e.g 4 x 0.75), metric Fine (e.g. 9 x 0.75), Metric Extra Fine (e.g. 8 x 0.75) and Others (e.g. 4 x 0.35, 8 x 0.75 etc.)
The same can be said for Imperial “standards” and while UNC, UNF and UNEF sizes and thread pitches are most common – older parts may be Whitworth , BSC (e.g. 5/16-26 or 3/8-26) and others (e.g. ¼-18 , 3/8-27, 3/8-40, 7/16-24, ½-24, ½-27, 9/16–28, and 5/8-32)
Pipe Threads are another whole deal – with NPT (and its NPTF variant) being common in the US – but being different (BSPP – BSPT) in Britain.
Metric or Imperial – I’m just happy that standardization seems to be more common today.
jeff
All imperial threads have 2 designations, I dont see how having 3 makes it more complicated.
Just like in imperial there are all of your popular thread pitches, its the same with metric.
Most of my work with metric fasteners are socket head cap screws, and the allen key sizes seem to be standardized.
Jeremy
In Canada we have an interesting mix. I think you will find that most people under 60 yrs old will use the following systems:
Weight/height of people- lbs/ft.
Temperature-deg. C
Distance of a trip(car/train/bike etc.) -kms
Distance in a room(length of a table/area of a house)-ft/inches.
Volume of a bottle-ml or l
Measurement of butter-lb
Weight of a product- could be either
Measurement of a volume for cooking- teaspoons/cups
It just is.
The nice thing about metric that many people don’t realize is the following(based on water, but things of similar density are generally close enough):
1 ml=1cc=1g. Sure makes conversions easy…
‘Hey, this says to add 100ml of water, but all I have is a scale!’ Easy-100 grams.
‘This bucket holds 20litres, how much do you think it will weigh full?” Umm, about 20kgs.
Awesome amiright?!
Stuart
1 gallon of water ~ 8-1/3 lbs. =)
Dan
Metric is good for Science and the water thing is useful but imperial is much better for building and I say this as someone who was educated in mostly metric and has learnt imperial from the old guys i work with. 12 divides up in more ways than 10 and thus is much more useful, also imperial make sense to the human body, you know how long a foot is but 300mm? A Lot of people have to get a tape out, same with yards, pounds or gallons (although ours are bigger than yours). We still use miles on road signs and measure ourselves in imperial and buy a lot of food and drink in whole pints or lb measures even though the shops have to sell it in metric.
The metric thread size is fairly simple as although there are different standards in the construction world virtually everything only uses one of them. Although we still have imperial pipe threads and if you like classic cars or bikes then imperial is still needed for them to, my local fixings place has UNF, UNC, Whitworth stuff on the shelf and even some cycle stuff. So even if you do end up metric the imperial system will be around for a long time
Scooter
Everyone uses metric, from militaries to weightlifters to drug dealers.
“imperial is much better for building”… and then as factual evidence, you cite personal preference and experience. The US and UK building (to a lesser degree) still clings to non-standard measurement systems, but US/UK building and manufacturing isn’t really competing for the world market anymore.
Old methods SEEM faster because we’ve memorized common conversions and values, so our brain is just accessing values from memories instead of solving for X. But multiply or divide imperial by 10 and your head explodes.
I am an American who is constantly exposed to “American Imperial”, but who uses metric for weights and distances. As an avid weightlifter and homebrewer, the metric switch was easy (see that bit about scaling… it’s no fun using ounces, cups and teaspoons either then scaling a recipe by 10X).
You re-learn new shortcuts through usage, so now I think in metric weights: 1kg=2.2lbs (just double, then add 10%). I don’t work in distances as much, so I think in US Imperial but can easily convert using 2.54 cm = 1 inch. I have no use for metric temperature. 🙂
Jeremy
Only in the US 🙂
Jeremy
(Is a gallon 8.3 lbs)
Doug
As a Canadian under 60 (57), I think you’re right-on with regards to which system is commonly used for what measures. We’re stuck here mid-transition between imperial and metric — mostly because the US reneged on it’s initial long-ago commitment to the international community to go metric.
Canada began the transition several decades ago… but because our giant neighbour and largest trading partner balked, we can’t complete the move to metric. So we’re currently stuck in this weird limbo between the two. (though that is mostly generational — Canadian kids are totally fluent in metric and barely use imperial, if at all)
On the other hand, I’m an anglo who lives and works in two languages and two measurement systems. Here in Quebec we use whichever language/measure is most appropriate for the immediate context and (language politics notwithstanding) nobody gets too miffed.
So for framing/carpentry I use imperial (2x lumber and 4×8 sheet goods) and when I’m cabinet-making I mostly use metric. (32mm system)
All of the rationalizations about why one system is inherently superior sounds too much like unilingual people’s rationalizations for why they’ve never learned another language.
And fluency across systems is about NOT translating, but rather understanding the different words/measures as they are, in their own context.
Preference is mostly about familiarity.
jeff_williams
I just prepared a proposal over the last few weeks for a building in another country. Honestly the design and pricing was all done in imperial and then converted to metric and local currency. My brain is used to the “feel” of imperial units despite the math being a no brainer in the metric system. I don’t resist the metric system but my brain is wired to the imperial one.
Scooter
” I don’t resist the metric system but my brain is wired to the imperial one.”
Exactly. It takes a LONG time before your brain switches to another system. It’s exactly like learning a foreign language. Learning is one part, but you really need to be immersed for it to become second nature. I’ve known people who live years in non-English speaking countries and interact with locals, and they say with time they can “think” a thought in that language without first converting it from English. It’s the same with metric (I use metric weights daily, so this is already natural to me).
RX9
The standard (imperial) system is nice in that it is (mostly) a base-2 system like binary code. In theory, this makes it simpler than the metric base-10 (decimal) system. In reality though, since most mathematical operations (especially in finance and science) are conducted in terms of the decimal system, metrics are more easy for most folks to make sense of.
If you work on cars built after 1975 or so, metric isn’t an option – its a requirement. Standard fasteners are used on houses, furniture and buildings, not vehicles. All three domestic manufacturers have been using metric for decades.
Keeping this in mind, what blows me away is how most auto parts stores seem to have more of a standard fastener selection than they do of metric. It’s as if the last 40 years of automotive history never happened.
Regardless of this, I can find whatever I need online anyway.
I like the metric system a lot, but I think the “if it ain’t broke, don’t fix it” attitude has been a pretty good thing. I feel wherever there is a financial advantage to going metric (like the auto industry) people will switch, and beyond that, people are best left using standard.
Scooter
I have a friend who argued against metric using the reasoning of no other countries but the US using it, so therefore it was some kind of jobs protection logic (they can’t figure the units out, so we won’t have competition from Japan and China). He’s since changed his argument to something else, but it’s just as based in emotion.
The financial benefit of Metric is: re-entering the world market for selling American goods. Unfortunately our economy is based on services and market speculation, so yeah no one cares if we live insulated from a STEM world that moved to metric decades ago.
Dennis
Metric is certainly easier for math, especially precision math. Unfortunately if you are consistently surrounded by a unit of measure you tend to think in that unit. So if I go to Home Depot it would come as a shock if plywood sheets came in 1.2m x 2.4m sizes. But I figure eventually you would get used to it.
I really “like” when the 2 units are mixed. My Ford has metric and SAE bolt sizes, I assume it’s to make things fun.
As a helpful hint I have found that a metric tape measure makes mounting Ikea products a hell of a lot easier.
Dan
Don’t worry about plywood going metric, its still 8′ by 4′ here in England we just buy it in mm. They changed bricks, blocks and drywall to easier metric dimensions, tried and failed to change doors and changed timber to metric but its not imperial or an easy metric, a 2″ by 4″ is actually about 96mm by 44 usually.
Dennis
Have they snuck out a 1/16 inch of thickness from the plywood? Like they are doing here in the US.
Dan
Its metric thickness generally but does vary a bit. Our system makes no sense.
Bruce
This comment on dimensions is exactly the problem. Just converting the numbers just makes the math when you are building harder. I’m not interested in 1.2m x 2.4m plywood. 1.5 x 3 would make way more sense. It makes it easy to calculate material needs. We live in a world where 2 x 4s aren’t 2 x 4s. Do you think it’s going to help when we start measuring them at 38.1mm x 89.9mm?
Scooter
“As a helpful hint I have found that a metric tape measure makes mounting Ikea products a hell of a lot easier.”
Yep. Amazon sells measuring tapes which are dual metric/US Imperial.
Joe M
I’m biased. I hate Math, so I use Metric on everything. I buy in metric, I build in metric, I design whatever I’m doing in Metric. I don’t have to visualize or anything, I just decide on a number. Like 10. Build everything around the number 10. 10 cm not enough? Try 20. Then, when something doesn’t fit, move the decimal. Out of 200 mm, how many have to be removed/added. Need to divide an odd number in half? Move the Decimal Place. 3 cm doesn’t divide in half well? Well, 30 mm does. Look on a tape measure and count off 15 of the smallest unit printed in metric, that is 15 mm, and nothing else. You find it very easy because every 10 of them, there’s a thicker line denoting a Centimetre. It’s not a fraction, you don’t need to know which denominator it is, or which fraction of a metre it is. It’s itself. 15 mm, or 1.5 cm. No Math, just count it and mark it. You don’t need a body part for reference, you don’t need to intuit anything, just hold up your measure and know every single time.
Temperature is tricky. Water freezes at 0 C, and boils at 40 C. Body Temp is between 34 and 38 for most people. (I may be biased, being Canadian and having the biology to withstand winters here may make me run a little hotter than human normal.) Fall weather between 5 and 12 C is wear-a-sweater-an-jacket cold, Spring weather between 5 and 12 is t-shirt weather. 20 is Warm. 30 is Hot. 35+ is Heat Wave and Dangerous. And anything between 0 degrees and -10 is Winter Jacket time. Anything between -10 and -35 is Don’t-Be-Outside-For-Long weather.
But, overall, the Metric System is superior in one very simple way. Take it or leave it, there is one standard measurement for everything in that category, and the unit only changes at certain decimal points to denote an easy marker.
Erik Potter
“Temperature is tricky. Water freezes at 0 C, and boils at 40 C.”
Not so much. Temperature is simple. Pure water freezes at 0 C at and boils at 100 C (at 1 atmosphere of pressure…”sea level”). Or for complex…water freezes at 32 F and boils at 212 F.
I’m an Architecture student. Unfortunately in the US we are hampered by being on the divide between SAE using professions (construction) and Metric using professions (engineering). So we have to produce plans in SAE that integrate metric systems designed by engineers or exist on site plans drafted by engineers. At least some of the engineering professions that still work in SAE use decimal instead of fractional systems (1.3″ instead of ~1-13/128″). That avoids at least some of the headaches, until you try to convert 1.3″ to feet.
I’m also a woodworker. I invested a lot of effort to go metric when I started assembling my tool collection for woodworking but the cost and scarcity of many things measured in metric was a hurdle here in the US. Given the near impossibility of getting everything here in metric and not wanting to deal with both SAE problems and conversion problems I grudgingly went mostly SAE.
“The standard (imperial) system is nice in that it is (mostly) a base-2 system like binary code. In theory, this makes it simpler than the metric base-10 (decimal) system.”
I’m not sure what the theory behind this is. The modern world out side of computers counts exclusively in base-10. That’s why the metric system was designed to work in the same way. 1000 millimeters is a meter. 1000 meters is a kilometer…but in SAE you have 12 points to the pica, 6 pica to the inch, 12 inches to the foot, 3 feet to the yard, 1760 yards to the mile. 43560 cu. ft. to 1 acre. 3 teaspoons to the tablespoon. 2 tablespoons to the fluid ounce, 8 ounces to the cup, 2 cups to the pint, 2 pints to the quart and 4 quarts to the gallon. How many teaspoons to a cup? How many cubic inches in a gallon? I don’t see how SAE can be viewed as essentially binary, as almost nothing is a doubling of anything else at all. Rather, everything has an archaic basis that means next to nothing to people today. I’m at least relieved that my water bill is not measured in hogsheads (that’s 63 gallons or 8.42 cu. ft.)
Remember, don’t forget to tip your waiter. Recommended gratuity is 3/20th to 9/50th of your bill. Many people have trouble figuring an approximate tip by doubling the sales tax or taking 10% of the bill and adding half again as much. If taking 2/1 or 3/2 of something is too complex, then being comfortably competent in SAE is out of reach.
Joe M
I only meant Temperature conversion between what most people using Fahrenheit are used to is tricky when thinking/imagining what it is in Celsius.
Though… I probably did get confused about what point Water boils at… I’ve always got them confused.
Caleb
Here is Colorado we have a lot of people who like to climb fourteeners – mountains with a peak over 14,000 feet in elevation. There are either 53 or 55 14ers depending on what standard you use to establish a “peak.” No one wants to climb “4,267.2ers.”
When hiking on relatively level surfaces, I plan on 2 miles and hour including breaks. When backpacking with a full load, 1 mile. 1,000 feet elevation change in a mile is about as step as you can hike, anything more is scrambling. And you would be lucky to do 1 in an hour. 🙂
I like that imperial is easier to divide into halves/quarters/etc. Especially with cooking/mixing.
When I need to, I can make rough sense of the metric distances – centimeter is just under 1/2″, meter is about a yard, and a kilometer is 5/8 a mile. I can’t get my brain around weight or temperature.
I have a foot. I don’t have a meter. I am almost 2 meters tall, but that is the least convenience way of estimating distance.
I am just glad that they didn’t come up with a different way of tracking time as well!
David
I have a foot also, and I’m nearly certain it’s a different size to yours 😉
JG
“No one wants to climb “4,267.2ers.”
This is where you are wrong. As an european mountaineer I can tell you that 4000+ meters alpine peaks is precisely the type of thing you describe. Reaching 4k meters is a rite of passage and people seem to like everything above that as it is seen as the top peaks level in the Alps.
Caleb
That may be true, but it lowers the minimum height requirement by almost 1,000 feet and you change the number of peaks to check off the list from 54 to about 550. 🙂 It is already hard enough to hit all 53-55 14ers, especially because of the few that are on private property.
Stuart
14,000 feet? Oh, you mean 2.65152 miles? Does anyone want to climb a 2.65152’er? =)
richard
I only use imperial for ratchets 1/4, 3/8, 1/2. those pesky 3/8th bolts that briggs and stratton uses when every thing else is metric and feet and inches when using a tape measure and i only go down to 1/4 inch sizes, none of these 1/8 or 64ths
Senorpablo
The best system is the one you know.
Also, some things are just better in standard units. For example, temperature in Fahrenheit is inherently more precise as commonly used; people don’t typically talk about Celsius temps in fractions and so you get a resolution of only 1.8 degrees F for a degree C. That’s significant when you’re talking about body, air, water, or cooking temps. Another example is machining. Thousandths of an inch is a fantastic unit for precision manufacturing. All the resolution is there without typically having to go into ten-thousandths. No fussy decimals to worry about.
Fractional inches can be a pain, but so too are metric hardware sizes in which there seem to be more than are needed. Starting at the 17mm range, for example, head sizes don’t seem significantly different enough to warrant the extra wrenches, sockets, fasteners etc. needed. Inch hardware seems to get the job done more simply in the regard that there aren’t many redundant sizes and tools.
I don’t see the US changing over. Think of all the billions of dollars in tooling and equipment that exists in standard only. Machine shops full of precision measuring and manufacturing equipment. CNC has made working in metric easier, but there are still lots of useful tools which cannot be converted to run in metric.
It’s interesting to note that aviation continues to be almost entirely standard system based. I’m sure this drives the French and Euros absolutely mad.
Jeremy
I will totally agree whatever you are used to is probably the best for ‘you’, since it is comfortable you are probably less likely to make errors etc.
However, these arguments about imperial being ‘more easily divisible’-SERIOUSLY?
Closely related is the argument for more easily break down to 1/4 or 1/2. Really?
If you know how to use money, I’m quite sure you will be fine.
As far as temperature, I know it doesn’t ‘make sense’ if you are used to faren. But can’t we agree that freezing as ‘0’ and boiling ‘100’ , considering the importance of those two states in Our lives, makes more intuitive sense than ’32’ and ‘212’?
Porphyre
Like many who have already posted, I like metric just fine, but I have NO IDEA how to estimate it.
I can hold my fingers 1 inch apart (25.54mm) but if you asked me to hold them 30cm apart, I couldn’t do it. Show me a 2.5 meter piece of wood, I’ll estimate it at 8 feet, then punch you. 🙂
Anything w/ metric involves a fast mental conversion to/from imperial.
Porphyre
Ug – 30 *mm* apart! 1.175″
Jeremy
Sure you could, you would just have to use two hands 😉
Stuart
1 inch = 25.4 mm
30mm = ~1.18 inches
I would just try to ballpark 1-3/16″ and would probably be close enough.
Jim
Another aspect of imperial / metric debate is the ‘compound’ measurements, like horsepower, velocity (ft/sec), mpg vs. liters/100km, BTUs, ft/lbs vs newton/meters, calories vs kilojoules, etc that we are used to. Some become confusing because they change the magnitude of the unit on both sides, such as a pump in gallons/minute vs. liters/second.
I still like automobile engine displacement in cubic inches and power in horsepower and foot/lbs of torque.
Stuart
I don’t bother converting from inch-lbs or ft-lbs to Nm or vice versa by hand anymore, I fire up Wolfram Alpha.
Jim
It is not about conversion, it is about point of reference. If I am in conversation and someone mentions to tighten a 1/2″ fastener to 85 ft/lbs, I know for that fastener size, it is within an acceptable range. If for the same fastener, they said 40, or 85, or 185 Newton/Meters one may not know which is appropriate.
Having a point of reference is extremely important as a secondary check. When working with unfamiliar units or in an unfamiliar environment, erroneous calculations with an order of magnitude can easily go undetected. I experienced this early in my engineering career. I might have had an input error or an erroneous measurement that would flow downstream into further calculations. Reviewing my work, a senior engineer with a point of reference, in seconds, could tell me I did something wrong. No detailed analysis required.
Wolfram Alpha ain’t gonna solve that.
Once you develop a frame of reference in one system, it is challenging to get that same level of fluency in another. Centimeters, liters, kilometers, grams…. Easy. That is like learning, 1,2,3, beef, chicken and beer in another language.
KenZ
Imperial, like right hand/left hand drive cars, is a travesty. So much efficiency lost. We should have stuck with the switchover in the 70s. Might have even saved us a Mars lander.
Chris Fyfe
I prefer Metric , I can function in either system . Metric is just more logical . British and E.U. tradesmen have been able to function , why not North America .
Chris
jeff
Born and Raised on Imperial, fought metric for a while, recieved a degree in mechanical engineering focusing on Imperial.
at home most of my projects that are put on my mill or lathe I design in metric. Drilled holes stay Imperial, while bored holes go metric.
much easier to do on the fly math in my head with metric than imperial.
jeremiah
How about engineer scale, as a grade engineer, and most dirt moving is done in engineer scale. One foot has ten tenths or 100 hundreths. Works great for math in the head as well as percentages, yards, tons ect. And as long as you dont need to be more precise the 1/8 inch your good
Michael Wright
Yes, indeed, Jeremiah. I am glad you brought up engineer scale practice. But, not just for grade engineering. Some folks mentioned thousandth’s of an inch or mills. A great many mechanical engineers (most?) use decimal inch practice: tenth’s, hundredth’s, thousandth’s, ten-thousandth’s of an inch. 0.1″, o.01″, 0.001″, 0.0001″, etc.
Oh yeah. 1/16″ = .0625, etc. But, we were born this way! At one time, way back I think in late 1970’s early 80’s, when the US was supposed to make the conversion to Metric, the Aerospace (giant) company I worked for for 42-years issued a “Metric Conversion” Booklet. And for a while (on some contracts) we actually had to “dual-dimension” the drawings – which was a fricken PIA.
But after a while more it was all forgotten when they refigured the extra cost added to the drawing preparation and release. Plus it fell out of the USAs future at that time.
george
having used metric most of my life I find it much better/easier.
now I’m struggling with imperial units. I now know what a 1/4 in is. I know that most manufacturers have gone to metric, specially those that sell world wide. so the u.s. has turned metric, just that no one realizes it.
mike
Sometimes I get parts to machine where the prints are metric. Its pretty easy to convert to inches and back to millimeters.
one millimeter = .03937 inches.
there are 25.4 millimeters in an inch.
All my guys always freak out when they see metric holes they need to tap even thou ive
shown them the methods many times.
Hang Fire
I was brought up as the confused generation. In school I was taught only Metric, because of course, Imperial/SAE was obsolete. Once I graduated high school I found all my (US) automobiles were SAE or mostly SAE. When I moved out I was given a cookbook by my Mom that was entirely Imperial.
Recently I worked with an architect to design my garage. I was told both by him and the general contractor to think in multiples of 2 feet.
We have a long way to go.
Garrick
I like both. I have to! I do woodworking in thousands of inches because 1/1000 of an inch is the right level of maximum precision, but the size of my yard is measured in how many feet I need to get across it or how many steps I take (yards… get it?) I do temperature in Farenheit for the better precision over Celcius. I prefer metric for nuts and bolts, because it’s easier than fractions. I like metric for food quantities for the same reason. Volume is easiest in metric, but my car knows miles per gallon best, so I stick with that. I am 5’9″, and weigh 25 pounds too much. Area and energy are best in metric.
I’ve learned to convert most everything to metric (kids… learn to convert metric to imperial… it’s good for your brains), but metric needs some improvements. First of all, it should be base 12, not base 10, for better division possibilities… 1,2,3,4 and 6 all go into 12 nicely. Boiling should be 200, freezing can stay at zero. That would mean 1 degree is about the minimum temperature difference a human can feel… which was the original idea of a farenheit. A metre should be what we now call 834.3 centimeters, because that is the length of a normal human step (normal being 5’9″).
It’s silly and sad to have based the whole metric system on something most people don’t even have any real feel for (one meter is 1/10,000 the distance from the equator to the north pole at the Grenwich meridian… albeit, it was not measured accurately to begin with, so a meter is in reality, a random distance). Time increments should be all in base 12 as well. However, there will always have to about 365 1/4 days in a year. Not much we can do about that.
Michael Veach
if the US had gone all metric 40 years ago, tool manufactures would have lost 50% of their sales. How many billion dollars would that be? There is no incentive to go all metric.
Hang Fire
The incentive for US Industry to “go metric” is clear- the prospect of exports to metric-centric wealthy countries with high import tariffs, and exports to developing countries that can’t afford our products.
Hey wait I think I may be on to something here….
Scottthetec
Most of the equipment I work on is metric, except for the pipe fittings (which apart from the final connection to the wall) are all British Standard Pipe – which is Imperial. I’ve never seen metric pipe fittings on a piece of European equipment.
I can now work with either.
Also, Boeing airplanes are machined Imperial; not sure about the the 787 though – that might be different.