You know, we covered all this just the other…
…wow, umm, I guess it’s been longer than I realized :eek:
Happily! There’s the 1/2 acre, the 1/4 acre, and though not all that useful in the real world, the 1/8 acre.
Where I come from (western Canada), measuring land in anything other than acres is a pain in the butt. Everythings surveyed in sections (sq mile) and quarter sections. An acre is a chain (16.5") on a half mile, so you can just measure your field on one side of the quarter section and know how big it is (assuming it stretches all the way across, but that’s usually the case). I like metric fine, but with the way the land was surveyed it will be a long time before people stop giving directions in rural areas in miles.
But see, this is where you’re making a compromise for easier math – according to Giles, you make this work by just throwing out any fractional millimeters. Now, I don’t know about you, but if a miter joint in cabinet work had a half millimeter gap in it, I’d feel like the work was absolutely subpar.
I’m hardly saying that the metric system produces inferior work. It comes down to preference and habit in the end. But the idea that the metric system is superior for this sort of thing hardly has a consensus in this country – as this thread shows. Obviously, for industrial or scientific use, particularly where other countries are involved, metric has a lot to recommend it, as plenty of posters have pointed out.
Incidentally, this is wrong. The U. S. does not use imperial units. We use American units, and I don’t think there’s any other accurate name for them. There is a system of units called imperial, which does bear some superficial similarities to American, but they’re not the same. An imperial pint, for instance, is 25% larger than an American pint (and likewise for quarts and gallons), and I’m pretty sure the teaspoons and tablespoons are different too. Which is another advantage of metric: Whenever anyone in the world says “liter”, they all mean the same thing.
Sal, yes, for some work, millimeter precision wouldn’t be good enough. In that case, you use tenths of millimeters, or micrometers, or femtometers, or whatever level of precision you need. Of course, one can also work in thirtyseconths of an inch or one-thousand-twenty-fourths of an inch or whatever is needed, but it’s a lot easier to add 5 mm + 4.3 mm than it is to add 3 1/8 inch plus 5 17/64 inch.
Takes me just as long to add the metric and fractional, especially when you use dividable denominators. At Boeing, everything is built in inches, we use 10ths and 100ths instead of 8ths and 16ths, it is just as easy to add as any metric measurement. Some tolerances are meausured in 10,000ths. And try to find a metric tape measure, the Home Depot near me doesn’t even carry them. The tool department manager said they use to carry them but they didn’t sell. I switch to the metric system the day they pry my Craftsman 9/16" wrench out of my hands.
Takes me just as long to add the metric and fractional, especially when you use dividable denominators. At Boeing, everything is built in inches, we use 10ths and 100ths instead of 8ths and 16ths, it is just as easy to add as any metric measurement. Some tolerances are meausured in 10,000ths. And try to find a metric tape measure, the Home Depot near me doesn’t even carry them. The tool department manager said they use to carry them but they didn’t sell. I switch to the metric system the day they pry my Craftsman 9/16" wrench out of my cold dead hands.
Hmm, that’s weird. Clicked submit reply, got the 404 error, page not found. Clicked back, made a quick change and clicked submit reply, now I have 2 posts.
And the same miter with a 1/64" gap would be about as bad 
Frankly that comes down to angular errors, not linear ones.
What I’m getting at is that I think people will make fewer mistakes if everything is in whole numbers, and the smallest basic metric unit in this case (1mm) is pretty close to the level of accuracy that is achieved. If you want to work to 0.5mm that’s great (better eyes than me!), but that still means your measurements tend to end in 0.0mm or 0.5mm, no biggie.
Look at it this way, if the basic unit of measurement was the Thingy, where one Thingy = 1/32", then you could pretty much do everything in whole numbers. Suppose you have to add 1 7/16" to 3/4" and subtract 1/8" and then divide by two…I dunno about you but I have to convert it all to 16ths and then do the math, so 23/16+12/16-2/16 = 33/16, divided by two equals 33/32nds.
If you were measuring everything in Thingies to begin with it’d be a little easier - 46+24-4, divided by 2, gives 66/2 Thingies or 33 Thingies. Minimal use of fractions, converting to a common denominator, etc. If you work to 1/64" tolerances and the first bit was actual 1 13/32" then you’d wind up with 65/2 Thingies thus 32.5 Thingies. Simple decimal. Your ruler wouldn’t even have a “3/4 inch” mark on it to begin with, just 24 (Thingies).
That’s fine for woodworking, but how about if the scale is much larger…battleship hulls, or Ringworlds? I can convert from millimeters to kilometers by just changing exponents. To go from Thingies to miles I’m going to have to break out the calculator (32x12x5280? Yuck). In this case simple powers of ten is far better than the hodgepodge of factors in English units. It may have made a great deal of sense in days of old to define an inch as “the length of three contiguous dried barleycorns” and the foot as “the length of his majesty’s right foot from the callus on his heel to the tip of his middle toe, after that hangnail is taken care of” but we don’t need to hang on to that.
When the scale gets really tiny everything goes by powers of ten anyhow, metric because that’s how it was designed and English because no chip designer wants to convert back and forth between 1/32,768th of an inch and 1/524,288th of an inch.
Sorry, that’s a very long-winded way of saying that the smallest unit should match the level of accuracy desired (thus making everything come out to whole numbers) and that converting up and down the scale should be simple. Metric does this quite easily. My “Thingy” system does the first but not the second since we’re still tied to the other English units.
OK, off to buy some metric rulers and tape measures and put my money where my millimeter is
…but a chain is 22’ (assuming you’re talking about what I think you mean)
An acre is one chain (22 yards) by one furlong (220 yards). Once you’ve driven your team for 220 yards they’re about ready for a rest while you turn the plough around, and when they’ve been up and down enough to plough a 22 yard strip, they’ve had it for the day.
Perfectly easy, yes. It’s about halfway between the 285.5 and the 286 mark on the ruler. Near as dammit.
Besides which, any system is going to have awkward divisors. But I can work out 2843mm less the end panel widths of 24mm each divided by 7 on a calculator in seconds. In fact, it doesn’t matter what combination of subtractions and divisions you throw at me, if it’s too hard to work out in your head you can use a calculator.
When you get to an awkward and complex division/subtraction in imperial, what do you do? A whole lot more keystrokes I’ll warrant.
Not inherently, only because you’re used to it.
A metric ruler has cm marks and mm marks. plus the 5th mm mark between each centimetre is usually bigger. Much less chance for confusion because there are fewer different marks.
Transplanted American living in almost metric country. After being here for a number of years, I pretty much have an instintive feel for metric dimentions now, including temperature, distance, lenghts, etc. Japan does most things metric, but keeps their old measurements for some things: office space (1 tsubo = 3.3 m2) apartment rooms are often measured by the number of tatami mats (180 cm X 90 cm), although they are going towards smaller mats. Irratating as all hell.
We moved office, and I would talk to real estate agents who would give the space in tsubo which I would have to convert to square feet for the head office to understand.
It’s easier to switch “cold turkey;” if you have the other unit there as well, then you just rely on the one you’re familiar with.
Fair point. Strictly speaking Imperial is the old British system, and our pints and gallons are a tad different from their US counterparts. Our inches used to be slightly different too, but they’re aligned now. But I’m still amazed that a country can send people to the moon in feet and inches, and shocked that Boeings are still specced in a similarly archaic fashion.
Just to redress the balance, I should point out that the US $ was the first decimal currency, where $1=100 cents.
Feck, yes, 22 yards not 22 feet :smack:
I’m all for conversion to metric. I can’t stand and never could stand imperial measurement. I remember in high school chemistry when we were only allowed to use metric. I thought I had died and gone to heaven. It doesn’t take long to get used to and to start to actually relate those numbers into the reality of everyday life. It becomes easy to know that 20 C and 68 F both equal pleasant days. Tell me it in millimeters and I can grok it. I never fully understood imperial anyway. Even today it confuses me. Yards, rods, acres. I still cannot effectively picture in my mind what an acre is. Give it to me in metric and I will understand. It’s math done easily in the head.
I’m no carpenter but when I’m doing projects on my house, I use the metric part of the ruler for myself but then give my GF the imperial measurement for her use.
It’s all relative and I think that it’s easy to train the mind to adapt to a new system.
Meh, that’s just my .02
Chronos is correct in that the U.S. does not use imperial units. However, the generally accepted name for the system of units used in the U.S. is the “U.S. Customary System (USCS).” This is the official term used by, for example, the National Council of Examiners for Engineering and Surveying (NCEES).
There is least one other difference between imperial and USCS, in that the USCS uses the pound-mass for the unit of mass instead of the slug. As mentioned previously, working with the pound-mass introduces the correction factor g[sub]c[/sub]. This factor creeps into all manner of equations, which makes engineering calculations of any complexity an absolute nightmare.
For example, kinetic energy: KE = mv[sup]2[/sup]/2g[sub]c[/sub], with KE in (ft-lbf). It gets progressively worse when you start dealing with fluid equations.
The metric (actually SI) is much easier to use.
I humbly stand corrected thanks to both of you. What is interesting is that the software I use for civil engineering and surveying (Softdesk/Land Development Desktop for those playing at home) specifically references these units as “Imperial Units”. Of course, they are only referencing units used in linear (or square or cubic) measurement, and not for volume or mass, so they might be *technically * correct if USCS and Imperial are in agreement on these units. Nevertheless, it is always good to know the correct terminology.
Drumming fingers here…
Well, the response to this has been nil. (Kinda expected to hear from, say, an SDSAB whose name elicited thoughts of time…) Was the lack of response due to pained embarassment over a stupid question, or has this been discussed to death? Should a day be “metricized” to ten hours? I don’t happen to think that it is feasible or likely, nor would I particularly want to see this, but I think as much of an argument could be made for this as adopting the metric system of measurement. I also know that the definition of a day as a unit is worthless when leaving Earth, and I’ve read enough Brian Greene to be confused when even talking about time, but it would seem that this would be the case with any unit of time, whether we based it on a day or on the rate of decay of a radioactive isotope. Is this worth a separate thread, or should I just let this die?
OK, I guess I have to answer that now. Any system of measuring time will have a problem, in that days and years are both rather essential units for human life, and there is not a nice tidy number of days in a year. So a total metrification of time is doomed to failure. The best we can do is to pick one unit of time and use that, and let days and years be whatever they are. And this is more or less what we do. We take the second as the metric unit of time (originally based on the day, of course, but it’s now defined in terms of a resonance of a particular atom, and the day is considered a measured quantity), and use that unit for everything metric. And then we have these other two units, the day and the year, that we’re just stuck with regardless.
There’s no contradiction in retaining current measurements of time and a uniform use of SI units (robby is quite right to emphasise that these are what we’re talking about, not some vague ‘metric’ phenomena)…because the SI unit for time is the second! That we choose to group these into sixties isn’t particularly important, any more than the choice of grouping kilograms by their thousand into metric tons.