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Ray

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Ray

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terryd said:As a Brit, I find the complications of the US so called imperial system mind boggling. One system for screw sizes, one for wood thickness and what on earth is a five penny nail and as for volumetric measures, forget it. How you citizens of the USA cope I really don't know. I've heard that we are two nations separated by a common language but the imperial system???

There are seven different barrel sizes used in the USA, with the size being dependent on the contents. Their names and metric equivalents are as follows: US cranberry (95.5 liters), US dry (115.628 liters), US liquid (119.24 liters), US federal (117.348 liters), US federal proof spirits (151.416 liters), US drum (208.4 liters), US petroleum (135 kg.), US petroleum statistical (158.99 liters).

The mnemonic goes "A pint's a pound the world around." Does an (American) pint of water really weigh a pound?

The short answer is no but it's close. A pint is 473 milliliters which would weigh 473 grams. A pound weighs 454 grams. Of course, for convenience, the pint (and gallon) differ depending on which side of the pond you're on.

Is a fluid ounce (floz) a measure of weight or of volume?

Despite the 'oz', floz is a measure of volume. Makes as much sense as anything else in the Inferial clusterf....

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Next week we'll move on to 'cauge' and 'rauge'! Youse ain;t ready for 'plough' or 'cheque' yet!Troutsqueezer said:I've learned a few things today, including how to spell "gage".

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Just be careful, though. Too many folks want to spell it "guage". Sadly, Guage is a small town in Kentucky and nothing else. It certainly isn't an alternate spelling of "gauge".Troutsqueezer said:I've learned a few things today, including how to spell "gage".

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Imperial system can either be decimal or fractional, the metric is only decimal.

It actually makes the imperial system far superior. If your doing calculations and complex math, fractions are necessary because they are more accurate, if you start rounding numbers, which is a requirement of a decimal based system, you can be far far off.

But I agree with practical everyday things, fractions need to go......decimal only baby. I can tell a .030 inch drill is bigger then a .020 inch drill by looking at the number, and I didn't use metric.

one could most certainly argue that metric decimal is more accurate as .001mm is far smaller then .001 inches, but then again, that's not REALLY practical for my everyday use

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If by superior you mean complicated then i agree ;Drustyknife said:Imperial system can either be decimal or fractional, the metric is only decimal.

It actually makes the imperial system far superior

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There are a couple of things there that complicate matters (as if they were not complicated enough ???).mklotz said:...........The mnemonic goes "A pint's a pound the world around." Does an (American) pint of water really weigh a pound?

The short answer is no but it's close. A pint is 473 milliliters which would weigh 473 grams. A pound weighs 454 grams. Of course, for convenience, the pint (and gallon) differ depending on which side of the pond you're on.

Is a fluid ounce (floz) a measure of weight or of volume?

Despite the 'oz', floz is a measure of volume. Makes as much sense as anything else in the Inferial clusterf....

A UK pint is about 20% larger than a US pint at about 568 cc (millilitres) and there are 20 fl oz in our pint and they weigh exactly one oz (Avoirdupois system, not Troy -which has 12 oz per lb- used for precious metals etc) and an English gallon weighs exactly 10 pounds as there are 8 UK pints to a UK gallon. The mnemonic a

Regards all,

Confusedly yours,

Terry

Aah, but if you break it down further the numerator and denominator numbers of those fractions - they are decimals, which uses the same base as the metric system.rustyknife said:It actually makes the imperial system far superior. If your doing calculations and complex math, fractions are necessary because they are more accurate, if you start rounding numbers, which is a requirement of a decimal based system, you can be far far off.

I don't mind the fractions, what gets me is the tap sizes like 10-32 where the number 10 is simply used designate the screw size. It's a 3/16 diameter screw so why not call it a 3/16 - 32?

I personally prefer Imperial. Units are based on what are useful human-scale dimensions. The irrationality of it all appeals to me. The mental conversion required I consider to be a statement against the dumbing-down of America. ;D

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my lathe is metric but is a diameter lathe i.e. the dials are marked up in such a way that 1 on the dial takes off 1 mm off the dia.

that being said if I set the digital calliper to the size I require and do not move the jaw but zero the display measure the work piece and the number displayed is the amount to take off , just dial it in with the dials on the feed screw

If per chance I need to do imp set the calliper to imp measure , zero and flip the units and continue as above,

Note no nasty maths involved let the tools do the work

Stuart

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You could argue that if you want to compare apples and oranges. Any measurement can be made as finely as equipment permits in any measurement system.rustyknife said:one could most certainly argue that metric decimal is more accurate as .001mm is far smaller then .001 inches...

Talking about the "accuracy" of a measurement system is pure nonsense. All measurement systems are based on arbitrary standards whether it's nose-to-thumb distance or pole-to-equator distance. Accuracy is defined by the tools used to make the measurements, not the measurement system itself.

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You must be a deliriously happy man then.Mainer said:I personally prefer Imperial. ... The irrationality of it all appeals to me.

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Ah yes I agree about the absolute accuracy of fractions, but there are many more mistakes made multiplying and especially dividing fractions, especially as mental arithmetic, and as for dissimilar fractions Woah!. What do I hear? "Convert them to decimals to simplify the task". There's a good idea".rustyknife said:........................Imperial system can either be decimal or fractional, the metric is only decimal.

It actually makes the imperial system far superior. If your doing calculations and complex math, fractions are necessary because they are more accurate, if you start rounding numbers, which is a requirement of a decimal based system, you can be far far off

Also remember as others point out, the World, the Universe and our measurements aren't absolute, only relative. The world is one whole big exercise in compromise as is my model engineering and it's a losing battle trying to fight that fact.

I found out today that experimenters have now discovered that Britain rises about 120 mm as our tectonic plate moves under the effects the water mass in a high tide, that's twice a day. As our weight depends on the distance from the centre of the Earth (distance between the centres of 2 masses) I therefore decree that I will only weigh myself at high tide. - must go and check the tide tables for absolute accuracy

Regards

T

You may have something there Terry. I could open a weight loss clinic on top of 14,115 foot Pike's Peak. Not many other

places in the country that a person would weigh less.

Quite right Marv....in the Ultra precision world like fractions of nanometers...everything is measured with white laser.....no micrometers need apply....once the computer counts the fringes....you can output to either system....mklotz said:You could argue that if you want to compare apples and oranges. Any measurement can be made as finely as equipment permits in any measurement system.

Talking about the "accuracy" of a measurement system is pure nonsense. All measurement systems are based on arbitrary standards whether it's nose-to-thumb distance or pole-to-equator distance. Accuracy is defined by the tools used to make the measurements, not the measurement system itself.

Accuracy comes down to the instrument used.

Dave