The 39th Root of 92 • Hacker News Board

Re: The 39th Root of 92

#111

Post by fennecfoxen » Mon, Aug 08, 2016, 5:58 AM UTC

billforsternz wrote: post #106

fennecfoxen wrote: post #76

Earlier quoted context omitted.

"Extraordinary gains?" Ordinary gains are about 4% a year (long-term returns of broad investments in the stock market, adjusted for inflation). If you buy a piece of equipment for $100 it should return $4/year (on top of maintenance costs, depreciation, and the like) otherwise you'll do better by buying a stock-market index fund. How much do you think it would cost an arbitrary manufacturing company to switch over al…

Clearly I was talking about switching the entire American society from imperial to metric. Your switch of focus to the impact on a single company and it's return on capital is certainly interesting but I am not 100% convinced it's germane. It's not necessarily a good idea to apply a Wall Street lens (quarters trump decades!) to every decision. Other countries around the world have successfully absorbed the short term…

Other countries around the world have wasted billions and trillions on a lot of things (senseless wars, for starters) and gotten through the short-term pain that this has caused - that doesn't mean it was a good idea.

If nothing else, the $N billion of nationwide switching costs could have been used on, like, renewable power, or something.

Re: The 39th Root of 92

#112

Post by fanf2 » Mon, Aug 08, 2016, 6:04 AM UTC

jacobolus wrote: post #47

Turing_Machine wrote: post #43

Earlier quoted context omitted.

For some value of "nice round number". What really matters with most wires is the current carrying capacity, which largely depends on the cross-sectional area , not the diameter. Equally-spaced diameters don't give you equally-spaced areas.

If you have an industrial production process which is going to produce a set number of wire sizes, and you want them to be maximally useful for a wide variety of applications, you want a logarithmic scale. Responding to commenter e2e8: Using 2mm, 3mm, etc. would be substantially less functional. Once you have a log scale, it hardly matters whether you measure diameter or area, that’s just a constant factor. In the id…

AWG is exponential not logarithmic.

For an exponential scale you can just pick some reasonably evenly-spaced round numbers and repeat them at different factors of 10: 1, 2, 5, 10, 20, 50, ...

Re: The 39th Root of 92

#113

Post by jeremysmyth » Mon, Aug 08, 2016, 10:31 AM UTC

"In metric, one milliliter of water occupies one cubic centimeter, weighs one gram, and requires one calorie of energy to heat up by one degree centigrade—which is 1 percent of the difference between its freezing point and its boiling point. An amount of hydrogen weighing the same amount has exactly one mole of atoms in it. Whereas in the American system, the answer to “How much energy does it take to boil a room-temperature gallon of water?” is “Go fuck yourself,” because you can’t directly relate any of those quantities."

- Wild Thing, Josh Bazell

Re: The 39th Root of 92

#114

Post by billforsternz » Mon, Aug 08, 2016, 10:52 AM UTC

fennecfoxen wrote: post #111

billforsternz wrote: post #106

Earlier quoted context omitted.

Clearly I was talking about switching the entire American society from imperial to metric. Your switch of focus to the impact on a single company and it's return on capital is certainly interesting but I am not 100% convinced it's germane. It's not necessarily a good idea to apply a Wall Street lens (quarters trump decades!) to every decision. Other countries around the world have successfully absorbed the short term…

Other countries around the world have wasted billions and trillions on a lot of things (senseless wars, for starters) and gotten through the short-term pain that this has caused - that doesn't mean it was a good idea. If nothing else, the $N billion of nationwide switching costs could have been used on, like, renewable power, or something.

It sounds as if you really think it's a good idea to stick with imperial. In your opinion is this a common attitude within the technologically sophisticated section of US society? I didn't think it was but maybe I am mistaken.

Re: The 39th Root of 92

#115

Post by exDM69 » Mon, Aug 08, 2016, 11:11 AM UTC

adrianratnapala wrote: post #89

exDM69 wrote: post #75

Earlier quoted context omitted.

In imperial vs. metric, I don't think the actual units are as big of a difference as the convention of using fractions vs. decimals. When doing manual work, e.g. woodworking or metalwork it's pretty convenient to use fractions. You tend to divide things in half or quarters. With most things not made by hand any more, using fractions and inconsistent units like inches, feet, yards and miles is a nuisance for engineers…

Inches, feet, and yards and miles aren't really inconsistent, becuase they are all related by somewhat reasonsable integer ratios. In this computer age, there isn't even much advantage in replacing all those ratios with powers of ten. It's when people inflict mixtures of BTUs with h or Joules with eV on us that I get aggravated. Each of those units has its place, but only in particular domains. Worse, the people most…

If you're working with floating point in meters, all it takes is a look at the exponent (e.g. 1.75923e-5) to figure out whether it's micrometers, centimeter or kilometers. Not as practical with a non base-10 unit system.

Re: The 39th Root of 92

#116

Post by danny8000 » Mon, Aug 08, 2016, 3:30 PM UTC

ysleepy wrote: post #3

I continue to be baffled by the arcane units in the US. This uses a measure on the completely wrong abstraction level. An accidental production process now defines a wire unit instead the end result the consumer/engineer/technician wants to know (mm^2 or inch^2 oh no no it's pica^2 ?). There must be some sociological phenomenon going on that keeps the US from adopting modern units. Maybe can't admit a shortcoming and…

I remember when reading "Napoleon: A Life" by Andrew Roberts, Napoleon wasn't a big fan of the base-10 metric system, but he figured it would be the best way to break with the hundreds of different measuring systems in place in France at the time, and enforce an empire-wide standard.

I much prefer base-12 or base-16 systems, especially when measuring and hanging drywall!

On the other hand, the British waited way to long (until 1971) to decimal-ize their currency. Before that the pound was made up of 240 pence.

Re: The 39th Root of 92

#117

Post by int_19h » Mon, Aug 08, 2016, 8:22 PM UTC

Turing_Machine wrote: post #90

int_19h wrote: post #61

Earlier quoted context omitted.

Open Amazon, and search for something as mundane as plastic bags or trash cans. Notice that their thickness is specified in "mils". How many people make purchasing decisions on those products, for use in their daily lives?

All you need to know there is that a 3 mil is thicker than a 2 mil. That doesn't require any kind of calculation at all.

Most units are used in the same manner - no-one is mentally converting kilometers into meters to compare two km distances, for example.

The point is that people do have a need for units that are tiny fractions of an inch, even in day to day life.

Re: The 39th Root of 92

#118

Post by fennecfoxen » Mon, Aug 08, 2016, 8:29 PM UTC

billforsternz wrote: post #114

fennecfoxen wrote: post #111

Earlier quoted context omitted.

Other countries around the world have wasted billions and trillions on a lot of things (senseless wars, for starters) and gotten through the short-term pain that this has caused - that doesn't mean it was a good idea. If nothing else, the $N billion of nationwide switching costs could have been used on, like, renewable power, or something.

It sounds as if you really think it's a good idea to stick with imperial. In your opinion is this a common attitude within the technologically sophisticated section of US society? I didn't think it was but maybe I am mistaken.

I prefer metric, from a policy perspective, I just think the path dependence has too strong a case to revamp industrial toolchains. (Changing the road signs and temperatures, by contrast, is both trivial and useless.)

Other things which are better that we'll probably never have include broader gauge railways, Dvorak for everyone, Wankel engines, and Betamax (vs VHS).

Re: The 39th Root of 92

#119

Post by int_19h » Mon, Aug 08, 2016, 8:43 PM UTC

kevhito wrote: post #85

int_19h wrote: post #60

Earlier quoted context omitted.

The "it's more natural" argument, fielded by both sides, is largely a myth - take it from someone who lived in several countries and struggled with different units. Pretty much the only reason why something feels natural to you is because that's what you are accustomed to using. There's nothing more natural about an inch than a centimeter, and nice, round, easy-to-remember numbers can be had on both scales for "natur…

You may have a point when it comes to mm vs. inches, etc. But my post was about logarithms vs. cross-sectional area vs diameter vs. circumference. Does your point still hold?

It's really a question that ought to be asked to someone who actually deals with wires in the industry as their day to day job, but I suspect that area is actually the most useful metric, because it can be directly plugged into formulas for tensile strength and electric resistance.

This doesn't really preclude a logarithmic scale, but it should be the kind that's easy to convert (i.e. increasing numbers denote increasing area). Looking at AWG, it could actually even be decimal, like dB. Consider: 17 gauge is almost exactly 1 mm^2 in area, so if we pick exactly mm^2 as 1 on our hypothetical scale, then 10 would be 10mm - close to 7 gauge, and -10 would be 0.1mm - close to 27 gauge. And there are plenty of industries that already know how to work with dB scale, and use the shortcuts that it offers.

By the way, while looking up related things, I've discovered the existence of a weird unit called "circular mil" (basically, cross-section of a wire 1 mil in diameter) that is, apparently, already used in US for wires that are out of bounds on AWG gauge scale. Which seems to indicate that cross-section area is, indeed, the preferred metric.

Re: The 39th Root of 92

#120

Post by Turing_Machine » Mon, Aug 08, 2016, 11:03 PM UTC

int_19h wrote: post #117

Turing_Machine wrote: post #90

Earlier quoted context omitted.

All you need to know there is that a 3 mil is thicker than a 2 mil. That doesn't require any kind of calculation at all.

Most units are used in the same manner - no-one is mentally converting kilometers into meters to compare two km distances, for example. The point is that people do have a need for units that are tiny fractions of an inch, even in day to day life.

Miles and km are the same, just on the the other end of the scale. A straight magnitude comparison requires no calculation.

The units that people need to perform calculations with are the ones used in measuring for cooking, sewing, home improvement projects, and things of that nature.