51–60 of 69 posts
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Yeah, it's a bit of weird disjoint. Almost a tacit admission, in fact. I've heard that in some crazy parts of the world - say 95% of the planet - it's base-10 all the way down . Makes you wonder if they're on to something with that kind of whacky scheme. Hopefully it works out for them.
How do they measure out ⅓ and 1/6 and 1/12 using only base 10?
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Disposable gloves are also measured in mils. When I bought a micrometer one of the first things I measured was a disposable glove and I was concerned that the measurement was really wrong. Then I searched online and found that the specified thickness is only on the finger pad area of the glove. Measuring there was dead on.
> the specified thickness is only on the finger pad area of the glove TIL. Thanks for sharing that, this is handy to know.
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Yeah, it's a bit of weird disjoint. Almost a tacit admission, in fact. I've heard that in some crazy parts of the world - say 95% of the planet - it's base-10 all the way down . Makes you wonder if they're on to something with that kind of whacky scheme. Hopefully it works out for them.
How do they measure out ⅓ and 1/6 and 1/12 using only base 10?
Earlier quoted context omitted.
My sophisticated wild-ass guess: Film and sheet thicknesses are often specified in mils, and PCBs are essentially fancy sheets of stuff laminated together. My unsophisticated wild-ass guess about why they persevere: Like Fahrenheit, it so happens that mils as a scale intuitively correspond to sizes of trace we care about. A 5 mil trace is pretty run of the mill for signals. 20 mils for most IC supply traces. 3 mils i…
People in metric countries just learn to be comfortable with decimals. So you end up with trace widths like 0.5mm or 0.3mm and you just get used to it. I think the intuition argument is often just a post hoc assumption for things that we are actually just familiar with.
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> Ounce / fluid ounce is roughly the same as gram / milliliter. That's how it's used, but the units don't measure the same thing. It's like measuring an engine's power output in square meters, because a kilowatt is about a square meter of sunlight.
> That's how it's used, but the units don't measure the same thing. I'm having some real trouble parsing this sentence right here. You're saying that the two DIFFERENT UNITS "fluid ounce" and "ounce (weight)" measure DIFFERENT things? Yes, different units measure different things. Or maybe I don't understand what you are trying to say here. If I said "kilogram force", you'd know exactly what that is. You are also not…
"degrees" is an interesting one, as it's really just another word for "amounts" or "units" or "subdivisions". 100 degrees centigrade is 100 amounts of centigrade. Or actually Celsius, as "centigrade" means "100 subivisions". The name of the unit is just "Celsius".
Really, degrees of arc should probably have been given a "proper" name too, but it's too late for that. Or you could switch to radians ;-p
Language is fuzzy. People know what you mean when you say "degrees centigrade" or "fluid ounces", so it's fulfilled its purpose. But that doesn't mean that some "proper" terms for measurements aren't weirder than others. "Celsius" is straightforward and unambiguous. "fluid ounces" is kinda weird. And yes, "degrees (of arc)" is a poor choice of unit name, worse than "fluid ounces". That still doesn't make "fluid ounces" good though.
Curious why we jump from 16ths or 32ths to thous rather than 64ths, 128ths, 256ths, 512ths and 1024ths I guess they are a mouthful without good abbreviations and there was a tech jump between woodworking and machining so in betweens aren't used
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> That's how it's used, but the units don't measure the same thing. I'm having some real trouble parsing this sentence right here. You're saying that the two DIFFERENT UNITS "fluid ounce" and "ounce (weight)" measure DIFFERENT things? Yes, different units measure different things. Or maybe I don't understand what you are trying to say here. If I said "kilogram force", you'd know exactly what that is. You are also not…
I think the GP's point was that "fluid ounce" is a measure of volume, not mass or weight. If you're measuring a liquid whose density is different from water, a fluid ounce won't weigh anywhere near an ounce. "degrees" is an interesting one, as it's really just another word for "amounts" or "units" or "subdivisions". 100 degrees centigrade is 100 amounts of centigrade. Or actually Celsius, as "centigrade" means "100 s…
Yes, and equally so, if you are measuring a substance other than water, the milliliter will have a different mass than a gram.
What I find amazing is that one thousandth of an inch is not particularly precise when it comes to machining. You can easily make parts to that accuracy with common mills and lathes. Also surprisingly (to me) is if you have a pin that goes into a hole that is 1-2 thousandths of an inch larger than the pin, it feels like a sloppy loose fit. If you want the pin to feel like a really nice smooth fit you need more like a…
Yea, I'm always blown away by the old master machinists I've worked with when they talk about getting to "50 millionths" (ie half a tenth of a thou) on manual lathe and measurable with a bench micrometer [1]. Also the auto body guys whose hands are like profilometers [2] and can just feel various surface quality [3]. This is actually where precision originally came from with the 3 plate lap where you're just using fi…
He fan feel thousands of inches and can note the individual thickness of each card he touches.
He is also 100% blind, and he talks about how sensitive his touch is.
He is unbelievably remarkable
https://en.wikipedia.org/wiki/Richard_Turner_(magician)
the documentary he is in is called "Dealt"
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Yea, I'm always blown away by the old master machinists I've worked with when they talk about getting to "50 millionths" (ie half a tenth of a thou) on manual lathe and measurable with a bench micrometer [1]. Also the auto body guys whose hands are like profilometers [2] and can just feel various surface quality [3]. This is actually where precision originally came from with the 3 plate lap where you're just using fi…
You should watch the documentary on the most famous Card Mechanic (Card Magician, but they like to go by 'mechanic') - Richard Turner. He fan feel thousands of inches and can note the individual thickness of each card he touches. He is also 100% blind, and he talks about how sensitive his touch is. He is unbelievably remarkable https://en.wikipedia.org/wiki/Richard_Turner_(magician) the documentary he is in is called…
Curious why we jump from 16ths or 32ths to thous rather than 64ths, 128ths, 256ths, 512ths and 1024ths I guess they are a mouthful without good abbreviations and there was a tech jump between woodworking and machining so in betweens aren't used
Mils are awesome for wire thicknesses, trace widths, pin spacings on circuit boards, fine drill bit sizes for through holes ... Guitar strings are, e.g. 9 to 46: .009" high E, .046" low E. Classic DIP (dual in-line package) integrated circuits and headers have 100 mil spacing: ten pins per inch. IIRC, you drill a 25 mil hole for the pins. This is international. The metric system doesn't have a nice mil-like unit for…
But that's just a historic accident.
Related, the metric system was forced upon trade in Germany not before the early seventies. Only few units previously used survived, e.g. the 'Pfund' (pound, now redefined as 'half kg'). My father continued to use 'Zoll' (inch) and lamented American made machinery using threads on nuts which differed from those used in Germany (and everywhere else). Even I know the folding carpenter's ruler only as 'Zollstock' (no one says 'Gliedermaßstab').
And while I used to be very opinionated about the imperial- vs. metric system, after twenty years in California, I feel comfortable at 75°Fahrenheit and am exhausted, if I have to walk more than a few miles. I even caught myself recently referring to a width as 'about a yard'...