4 ms·

In industry, we have. At home, most households have little or no use for US dimension tools such as wrenches. You can service a bike with all metric tools. "Go

In industry, we have. At home, most households have little or no use for US dimension tools such as wrenches. You can service a bike with all metric tools. "Going metric" raises the question of whether we adopt metric measures for our existing standards (such as pipe threads) or actually adopt the ISO sizes. The latter would cause a brief but massive inventory management problem, that nobody's ever willing to put up with, even if there's a long term benefit. I believe we made a mistake in how we tried to teach the metric system. I learned in first grade: Metric is easy because it's just math. Most people heard "math" and freaked out. Metric was taught as a bunch of conversions and units. Inches were taught as: Here's a ruler, go measure some things. I remember talking to a machinist, and he said: "I hate the metric system because there's so much math." That was 30+ years ago. Today, machinists just read mm or inches from the same digital readout or CAD program. My Canadian friends learned metric as: Here's a ruler, go measure some things.

perilunar 5mo ago
> "Going metric" raises the question of whether we adopt metric measures for our existing standards (such as pipe threads) or actually adopt the ISO sizes. You adopt ISO sizes FFS. They are international standards. You really want to invent a whole new set of incompatible 'standards'? You think the US is the first to go through this? Australia, Canada, and the UK went metric in the 1970s (we also decimalised our currencies). Yes it was challenging for some adults but mostly pretty easy for kids. People adapted. Industries adapted. Now we hardly think about it except when dealing with Americans or in some historical contexts.
- SoftTalker 5mo ago
  For the piping example, you have all the installed infrastructure that's in the old "IPS" (straight) and "NPT" (tapered) sizes. So now a plumber needs to carry additional fittings or carry conversion fittings. Easier to just stay with what we have.
  - perilunar 5mo ago
    Of course it's easier to stick with what you have in the short term. Change is difficult. You do it for the long term gain. If you had done it 50 years ago like the rest of the English-speaking world you wouldn't be in this mess.
    - SoftTalker 5mo ago
      What's the long term gain? It's just a unit of measure, ultimately arbitrary. Standards bring efficiency, and we already have a standard.
      - crote 5mo ago
        Exactly: the entire world has a standard, and the US is doing its own weird thing. The long-term gain is being able to sell your stuff to the rest of the world, and being able to import stuff from the rest of the world without paying a Weird Format Tax. Would you rather manufacture stuff for 8 billion people, or for 340 million?
        SoftTalker 5mo ago
        You could also argue that North America should convert to 50hz 220VAC for electric services, so that one line of products could be sold to the entire world. But the switching costs would be huge and manufacturers generally have no problem making the few changes that are needed to make products for export, or when possible designing their products to accept either standard. Cutting metric or imperial threads in a pipe fitting is a programming code change in a CNC machine, and maybe using a different cutting tool. Easily done for an order that's going to be exported. So I don't think manufacturing is a big concern, and not the reason we've stayed with old standards in many cases.
      - mahkeiro 5mo ago
        Maybe avoid to crash half a billion $ probe on Mars surface?
- PaulDavisThe1st 5mo ago
  The UK continues to live on in a weird metric-imperial mash up. Beer is still measured in pints, lots of food (but not all!) is measured in pounds, distance and speed limits are sign-posted in miles, but the sizes of most things in life are in cm, mm and meters.
  - SturgeonsLaw 5mo ago
    Not to mention measuring people's weight in stone
SoftTalker 5mo ago
Imperial measurements do have the benefit of more even divisors than metric. Pretty common to talk about measurements of 1/2, 1/4, 1/8, 1/16 of an inch and find those graduated on a ruler. Or 1/2, 1/3, 1/4, 1/8 of a cup for liquid measures, etc. But then machinists generally work in thousandth or ten-thousandths of an inch.
- analog31 5mo ago
  I'm a fairly experienced machinist, though it's not my occupation. At the present time, machinists have the least problem with metric. The unit conversions are built into all of the machines and measuring tools. You press the inch / mm button. The ruler has inches on one side and mm on the other. Everything is standardized on IEEE floating point. ;-) It's a headache to maintain collections of parts and tools such as taps and dies for both standards. The biggest shift is simply the obsolescence of old stuff, and emergence of new stuff. And industries have adopted the practice of reducing the overall variety of parts needed. I work in the development of industrial measurement equipment, and where a design might once have had 30 different sizes of fasteners, now it's 5, all metric. Designs rarely need nuts and spacers any more. Washers are integrated into the screws. No more "philips" or flat head screws. And so forth.
  - SoftTalker 5mo ago
    > Designs rarely need nuts and spacers any more. What is the modern approach where nuts/bolts and spacers would have been used? > No more "philips" or flat head screws. Torx? Rivets? Something else?
    - analog31 5mo ago
      Threaded holes and rivnuts. Now a rivnut is a part, but the fabricator keeps it in stock instead of us. More shaped stampings and castings so that spacers aren't needed. Reducing parts also reduces handling of parts. Probably CAD makes it easier to design these things in. At where I work, we use hex head (trying not to say Allen). I see lots more Torx in products as well.
- 5mo ago
dguest 5mo ago
I'm fine with math, but that doesn't make it less annoying. The real advantage of metric is that you only have to do math once to calculate something. A cc is a ml is a gram. A liter is a cubic decimeter is a kg. It's just easy. A deep lake over a few square km? O(1) GT. Understanding orders of magnitude is a useful trait in a democracy. You hit the nail on the head here though: > My Canadian friends learned metric as: Here's a ruler, go measure some things. Like any language, as long as you're translating you're loosing. Post signs in km and report temperature as C and everyone will understand it in less than a decade. A few years after I had a metric thermometer in my car C seemed easy. It's not like the US failed to think of this. In the 80s they were posting signs in km. But back then there was a real economic cost to conversion for factories and machines. Now that's mostly gone, what remains is cultural resistance.
- arealaccount 5mo ago
  > A cc is a ml is a gram. A liter is a cubic decimeter is a kg Okay but what about the off chance you’re measuring something other than water?
  - dguest 5mo ago
    Estimate as water and fudge it a bit. Conveniently the fudge factor is just the specific gravity and is already tabulated as such in a lot of fields. But it turns out that water is a pretty good bet most of the time: - Settled snow is around 0.25 - Dried wood is around 0.5 - Soil is around 1.2 - Rock is around 2.5 Which is pretty good if you want to answer "how much does that truck / ship / mountain / lake weigh?". Of course there are some anomalies: Tungsten is around 20, but it's not like imperial units help here, and the name literally translates to "heavy rock".
- analog31 5mo ago
  We have a saying in the US, "a pint's a pound, the world around." As the other post mentions, not everything has the same density, but a lot of stuff is pretty close to water. The ironic thing is that an Imperial pint of water weighs more than a pound.

perilunar 5mo ago

> "Going metric" raises the question of whether we adopt metric measures for our existing standards (such as pipe threads) or actually adopt the ISO sizes. You adopt ISO sizes FFS. They are international standards. You really want to invent a whole new set of incompatible 'standards'? You think the US is the first to go through this? Australia, Canada, and the UK went metric in the 1970s (we also decimalised our currencies). Yes it was challenging for some adults but mostly pretty easy for kids. People adapted. Industries adapted. Now we hardly think about it except when dealing with Americans or in some historical contexts.

SoftTalker 5mo ago
For the piping example, you have all the installed infrastructure that's in the old "IPS" (straight) and "NPT" (tapered) sizes. So now a plumber needs to carry additional fittings or carry conversion fittings. Easier to just stay with what we have.
- perilunar 5mo ago
  Of course it's easier to stick with what you have in the short term. Change is difficult. You do it for the long term gain. If you had done it 50 years ago like the rest of the English-speaking world you wouldn't be in this mess.
  - SoftTalker 5mo ago
    What's the long term gain? It's just a unit of measure, ultimately arbitrary. Standards bring efficiency, and we already have a standard.
    - crote 5mo ago
      Exactly: the entire world has a standard, and the US is doing its own weird thing. The long-term gain is being able to sell your stuff to the rest of the world, and being able to import stuff from the rest of the world without paying a Weird Format Tax. Would you rather manufacture stuff for 8 billion people, or for 340 million?
      - SoftTalker 5mo ago
        You could also argue that North America should convert to 50hz 220VAC for electric services, so that one line of products could be sold to the entire world. But the switching costs would be huge and manufacturers generally have no problem making the few changes that are needed to make products for export, or when possible designing their products to accept either standard. Cutting metric or imperial threads in a pipe fitting is a programming code change in a CNC machine, and maybe using a different cutting tool. Easily done for an order that's going to be exported. So I don't think manufacturing is a big concern, and not the reason we've stayed with old standards in many cases.
    - mahkeiro 5mo ago
      Maybe avoid to crash half a billion $ probe on Mars surface?
PaulDavisThe1st 5mo ago
The UK continues to live on in a weird metric-imperial mash up. Beer is still measured in pints, lots of food (but not all!) is measured in pounds, distance and speed limits are sign-posted in miles, but the sizes of most things in life are in cm, mm and meters.
- SturgeonsLaw 5mo ago
  Not to mention measuring people's weight in stone

SoftTalker 5mo ago

Imperial measurements do have the benefit of more even divisors than metric. Pretty common to talk about measurements of 1/2, 1/4, 1/8, 1/16 of an inch and find those graduated on a ruler. Or 1/2, 1/3, 1/4, 1/8 of a cup for liquid measures, etc. But then machinists generally work in thousandth or ten-thousandths of an inch.

analog31 5mo ago
I'm a fairly experienced machinist, though it's not my occupation. At the present time, machinists have the least problem with metric. The unit conversions are built into all of the machines and measuring tools. You press the inch / mm button. The ruler has inches on one side and mm on the other. Everything is standardized on IEEE floating point. ;-) It's a headache to maintain collections of parts and tools such as taps and dies for both standards. The biggest shift is simply the obsolescence of old stuff, and emergence of new stuff. And industries have adopted the practice of reducing the overall variety of parts needed. I work in the development of industrial measurement equipment, and where a design might once have had 30 different sizes of fasteners, now it's 5, all metric. Designs rarely need nuts and spacers any more. Washers are integrated into the screws. No more "philips" or flat head screws. And so forth.
- SoftTalker 5mo ago
  > Designs rarely need nuts and spacers any more. What is the modern approach where nuts/bolts and spacers would have been used? > No more "philips" or flat head screws. Torx? Rivets? Something else?
  - analog31 5mo ago
    Threaded holes and rivnuts. Now a rivnut is a part, but the fabricator keeps it in stock instead of us. More shaped stampings and castings so that spacers aren't needed. Reducing parts also reduces handling of parts. Probably CAD makes it easier to design these things in. At where I work, we use hex head (trying not to say Allen). I see lots more Torx in products as well.
5mo ago

dguest 5mo ago

I'm fine with math, but that doesn't make it less annoying. The real advantage of metric is that you only have to do math once to calculate something. A cc is a ml is a gram. A liter is a cubic decimeter is a kg. It's just easy. A deep lake over a few square km? O(1) GT. Understanding orders of magnitude is a useful trait in a democracy. You hit the nail on the head here though: > My Canadian friends learned metric as: Here's a ruler, go measure some things. Like any language, as long as you're translating you're loosing. Post signs in km and report temperature as C and everyone will understand it in less than a decade. A few years after I had a metric thermometer in my car C seemed easy. It's not like the US failed to think of this. In the 80s they were posting signs in km. But back then there was a real economic cost to conversion for factories and machines. Now that's mostly gone, what remains is cultural resistance.

arealaccount 5mo ago
> A cc is a ml is a gram. A liter is a cubic decimeter is a kg Okay but what about the off chance you’re measuring something other than water?
- dguest 5mo ago
  Estimate as water and fudge it a bit. Conveniently the fudge factor is just the specific gravity and is already tabulated as such in a lot of fields. But it turns out that water is a pretty good bet most of the time: - Settled snow is around 0.25 - Dried wood is around 0.5 - Soil is around 1.2 - Rock is around 2.5 Which is pretty good if you want to answer "how much does that truck / ship / mountain / lake weigh?". Of course there are some anomalies: Tungsten is around 20, but it's not like imperial units help here, and the name literally translates to "heavy rock".
analog31 5mo ago
We have a saying in the US, "a pint's a pound, the world around." As the other post mentions, not everything has the same density, but a lot of stuff is pretty close to water. The ironic thing is that an Imperial pint of water weighs more than a pound.