5 ms·

You just switch to miles for anything longer than a few hundred feet. Big units for big things, small units for small things. The flipside to this I’ve been en

You just switch to miles for anything longer than a few hundred feet. Big units for big things, small units for small things. The flipside to this I’ve been encountering a lot is engineering drawings in metric for things that are several meters long and all the measurements are in millimeters! Why all the big numbers!

teruakohatu 5y ago
> measurements are in millimeters! Why all the big numbers! Precision, usually if you are getting something fabricated the numbers are quoted in millimeters if the millimeters is under 10,000. So a desk might be 1800x800x700mm. I don't think I have ever seen something listed as 120000x10000x10000mm. At that point they would switch to meters.
- quartesixte 5y ago
  I have so many piles of drawings at work for all sorts of European manufactured machines that are about 6m in length that have their layouts (where mm level precision is silly and pointless) drawn out and measured in mm. 6000mm x 2000mm x 10000mm etc etc. It’s like...why?? As for the precision, I suspect it’s to defeat the perils of floating point numbers in computers...if you only need mm precision, you rather your CNC computer do integer math and not floating point math...am I correct?
  - teruakohatu 5y ago
    Because if everyone millimeters then there is no confusion. For that reason I rarely see anything non-consumer specified in cm. > CNC computer do integer math and not floating point math...am I correct? Good point.
  - actually_a_dog 5y ago
    > As for the precision, I suspect it’s to defeat the perils of floating point numbers in computers...if you only need mm precision, you rather your CNC computer do integer math and not floating point math...am I correct? I doubt that. It would be trivial to have the computer convert from 6.000m or 600.0cm to 6000mm internally.
  - chousuke 5y ago
    Why not, though? Millimeters are trivial to convert to meters in your head, since you don't need to calculate anything; just move the decimal point. Using millimeters gives you a "standard precision" which is a boon for interoperability.
    - quartesixte 5y ago
      >Why not, though? Because all my tape measures are in inches ;(
      - kaba0 5y ago
        You wouldn’t be helped by cm-s either :/
  - HPsquared 5y ago
    For precision work using inches, decimal thousandths of an inch ('thou') are typically used - for what I assume are similar reasons.

teruakohatu 5y ago

> measurements are in millimeters! Why all the big numbers! Precision, usually if you are getting something fabricated the numbers are quoted in millimeters if the millimeters is under 10,000. So a desk might be 1800x800x700mm. I don't think I have ever seen something listed as 120000x10000x10000mm. At that point they would switch to meters.

quartesixte 5y ago
I have so many piles of drawings at work for all sorts of European manufactured machines that are about 6m in length that have their layouts (where mm level precision is silly and pointless) drawn out and measured in mm. 6000mm x 2000mm x 10000mm etc etc. It’s like...why?? As for the precision, I suspect it’s to defeat the perils of floating point numbers in computers...if you only need mm precision, you rather your CNC computer do integer math and not floating point math...am I correct?
- teruakohatu 5y ago
  Because if everyone millimeters then there is no confusion. For that reason I rarely see anything non-consumer specified in cm. > CNC computer do integer math and not floating point math...am I correct? Good point.
- actually_a_dog 5y ago
  > As for the precision, I suspect it’s to defeat the perils of floating point numbers in computers...if you only need mm precision, you rather your CNC computer do integer math and not floating point math...am I correct? I doubt that. It would be trivial to have the computer convert from 6.000m or 600.0cm to 6000mm internally.
- chousuke 5y ago
  Why not, though? Millimeters are trivial to convert to meters in your head, since you don't need to calculate anything; just move the decimal point. Using millimeters gives you a "standard precision" which is a boon for interoperability.
  - quartesixte 5y ago
    >Why not, though? Because all my tape measures are in inches ;(
    - kaba0 5y ago
      You wouldn’t be helped by cm-s either :/
- HPsquared 5y ago
  For precision work using inches, decimal thousandths of an inch ('thou') are typically used - for what I assume are similar reasons.