The metric system sucks
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From: Andrew Usher on 15 Feb 2010 07:50 Michael Press wrote: > Try taking as contrary to my actual point of view > everything I said in my 9 February message. > Other messages of mine in this thread show > that I use all widespread units of measure > with equanimity and, in many cases, fondness. > > Ever notice how in a laboratory SI units must be > prefixed with power of ten notation to get the > numbers manageable? nm, GPa, Km, ug, ... Yes, you have. > All units must be made human sized for everyday work. That's true, so how does that argue for metric? > Those claiming that the metric system is the only > rational system, then using this claim to demand > that the USA go completely metric overlook the > powers of ten prefixes. They have to be accounted > for, and added in one's head to convert to SI units. > This conversion is not trivial, and it is bothersome. > I use strict SI units in all calculations. I convert > from conventional units (nm, GPa, ev, foot, pound...) > to SI, calculate, then convert back. It is the only > sensible way. Huh? It's not sensible at all. And didn't you just argue against metric? If you're going to do this, it's surely easier to have SI to start and end with. Andrew Usher
From: jmfbahciv on 15 Feb 2010 08:06 Andrew Usher wrote: > Matt wrote: >> On Sat, 13 Feb 2010 09:16:24 -0800 (PST), Andrew Usher wrote: >> >>> No, I have nothing against the cubit, if people find it useful. >> http://en.wikipedia.org/wiki/Cubit >> A cubit is the first recorded unit of length > > <snip> > >> I see nothing inherent in a meter to recommend it over a cubit. > > No, surely not. And I have nothing against the cubit. It just seems > redundant to the foot, which may be why it fell out of use. > >> And the Celsius temperature scale is just silly. Why throw away twice >> the whole-number granularity afforded by the Fahrenheit scale? Or the >> notion that 100 tends to suggest more of a milestone than 38 as a >> temperature extreme for comfort? Aren't the metric zealots gaga over >> powers of ten? Why not use a power of ten to describe a temperature >> that is extreme but survivable? Sterilizers operate near 100C. But >> the Celsius scale makes it easier for tabletop chemists to calibrate >> their thermometers. > > No, it doesn't, actually. If you want to measure the boiling of water, > it isn't any harder to use 212 F as 100 C - and you have to correct > for pressure anyway, to be accurate enough for calibration. > You obviously have not done any arithmetic. Using 212 instead of 100 is more difficult for every calculation. If you have your computer do it, it will be wrong. Using 100 implies that you don't have to do any numbers other than 1. /BAH
From: jmfbahciv on 15 Feb 2010 08:15 J. Clarke wrote: > jmfbahciv wrote: >> J. Clarke wrote: >>> jmfbahciv wrote: >>>> J. Clarke wrote: >>>>> jmfbahciv wrote: >>>>>> Andrew Usher wrote: >>>>>>> Bob Myers wrote: >>>>>>> >>>>>>>>> Drills already have interchangeable bits, >>>>>>>> Ah, another person who's never seen the inside of >>>>>>>> a machine shop... >>>>>>> OK, perhaps I didn't use the right terminology; I used that >>>>>>> which I am familiar. Nevertheless, my point stands that you >>>>>>> don't normally need a different machine for each different size >>>>>>> of drilling. >>>>>> Now ask the question why that is so. >>>>> I'm not sure I see the point of this particular discussion. Most >>>>> drills have three-jaw chucks that don't really require much of the >>>>> drill bit other than that it be round and not so big that it won't >>>>> fit in the hole or so small that the jaws won't close on it >>>>> (typically about a 20:1 range). Certainly no drill press I have >>>>> owned or worked with has had any trouble with bits that are >>>>> fractional inch sizes, metric sizes, or sizes that are pretty much >>>>> arbitrary. >>>>> >>>>> There are machines that require bits with tapered shanks or that >>>>> use collets that require shanks of a specified dimension and form, >>>>> or that require threaded shanks, but they are relatively rare--most >>>>> drilling is done with the bits secured in a 3-jaw chuck and 3-jaw >>>>> chucks are measurement-system agnostic. >>>> The reason that 3-jaw chuck exists is to adapt to any system: US, si >>>> or Sears. >>> No, it's to let you use the same drill with a tiny little bit or a >>> great big huge bit. The other option is to make the bit with a >>> standard sized shank, which means that the bits will all have steps >>> in them, which makes them more expensive to manufacture. >>> >>>>> Now if you're dealing with very small drills, circuit board drills, >>>>> and the like, they do often have a standard shank diameter, mainly >>>>> because their small diameter would make them difficult to handle >>>>> otherwise (like you'd need tweezers and a magnifier to change bits) >>>>> and there the measurement system does matter, but swapping out a >>>>> collet takes seconds. >>>>> >>>> Thus, the specification of the drills included adapting to any size. >>>> The reason for the generic is becuase there were more than one >>>> flavor. >>> Exercise--go down to Home Depot and look at the drill bits and think >>> about what they would have to look like if 3-jaw chucks that could >>> take any size were not in widespread use. Note that there are very >>> small ones and very big ones and ones in between. Then think about >>> how such a thing would be made. Then think about why anybody in his >>> right mind would make them that way if there was another option. >>> Then tell us whether you still think that the existence of 3-jaw >>> chucks has anything to do with metric vs inch. >>> >>> You usually come across as a very sensible person but on this >>> particular issue you're way off base. >>> >>> >> I'm thinking about how drills changed over the years _before_ >> electricity. I don't remember ever seeing hand drills with >> the option of changing the bits. Do you know the ones I'm >> talking about? You held the shaft with both hands and rotated; >> the shaft looked like a step-function graph. > > Carpenters's brace-and-bit, which used a square taper shank. So happens > that the two-jaw chuck for those was developed about the same time as the > three-jaw chuck for round bits in the late 1800s. Prior to that time a > square hole was used for the square taper shanks and collets for the round > bits. Neither had anything to do with the introduction of the metric > system. Kewl. Thanks. I'm haven't said that it has to do with the intro of the metric system. I was trying to talk about why a drill was designed to accept all sizes of bits. Read ^my line^ about adapting to any system: US, si or Sears. I was support the comment. Right after that someone disagreed. I think there is a passing of missed understandings here. > > Just as an example, a starter set of drill bits for someone taking up > machining in the US will have 115 bits ranging in diameter from 0.04" up to > 0.5". Any drill that will take all those bits will also take any metric bit > from 1mm to 12.5mm. Drills smaller than 1/4 inch or so with square tapered > shanks are rare--you won't find any in such a set no matter how old it is. > What you will find is a round taper, called a Morse taper, that was > developed in the US in the 1860s and is now subject of an ISO standard and > still in widespread use. The taper can be used directly to mount tooling, > but more commonly is used to mount a chuck. > > Further, the fact that a country is metric doesn't mean that all drill bits > used for machining come in even fractions of a millimeter. For example to > get a close clearance fit on a shaft that is 10mm +/- .0001, you'd need to a > hole that is between 10.013 and 10.055 mm diameter, or nominally 10.034mm. > > This is the nature of drilling and the reason that drills can take bits of > many sizes. > > By the way, power drills were in use long before electricity--they ran on > steam or water power. > Those power drills had to be stationary. How would you design a portable power drill that ran on water power? /BAH
From: J. Clarke on 15 Feb 2010 09:20 jmfbahciv wrote: > J. Clarke wrote: >> jmfbahciv wrote: >>> J. Clarke wrote: >>>> jmfbahciv wrote: >>>>> J. Clarke wrote: >>>>>> jmfbahciv wrote: >>>>>>> Andrew Usher wrote: >>>>>>>> Bob Myers wrote: >>>>>>>> >>>>>>>>>> Drills already have interchangeable bits, >>>>>>>>> Ah, another person who's never seen the inside of >>>>>>>>> a machine shop... >>>>>>>> OK, perhaps I didn't use the right terminology; I used that >>>>>>>> which I am familiar. Nevertheless, my point stands that you >>>>>>>> don't normally need a different machine for each different size >>>>>>>> of drilling. >>>>>>> Now ask the question why that is so. >>>>>> I'm not sure I see the point of this particular discussion. Most >>>>>> drills have three-jaw chucks that don't really require much of >>>>>> the drill bit other than that it be round and not so big that it >>>>>> won't fit in the hole or so small that the jaws won't close on it >>>>>> (typically about a 20:1 range). Certainly no drill press I have >>>>>> owned or worked with has had any trouble with bits that are >>>>>> fractional inch sizes, metric sizes, or sizes that are pretty >>>>>> much arbitrary. >>>>>> >>>>>> There are machines that require bits with tapered shanks or that >>>>>> use collets that require shanks of a specified dimension and >>>>>> form, or that require threaded shanks, but they are relatively >>>>>> rare--most drilling is done with the bits secured in a 3-jaw >>>>>> chuck and 3-jaw chucks are measurement-system agnostic. >>>>> The reason that 3-jaw chuck exists is to adapt to any system: US, >>>>> si or Sears. >>>> No, it's to let you use the same drill with a tiny little bit or a >>>> great big huge bit. The other option is to make the bit with a >>>> standard sized shank, which means that the bits will all have steps >>>> in them, which makes them more expensive to manufacture. >>>> >>>>>> Now if you're dealing with very small drills, circuit board >>>>>> drills, and the like, they do often have a standard shank >>>>>> diameter, mainly because their small diameter would make them >>>>>> difficult to handle otherwise (like you'd need tweezers and a >>>>>> magnifier to change bits) and there the measurement system does >>>>>> matter, but swapping out a collet takes seconds. >>>>>> >>>>> Thus, the specification of the drills included adapting to any >>>>> size. The reason for the generic is becuase there were more than >>>>> one flavor. >>>> Exercise--go down to Home Depot and look at the drill bits and >>>> think about what they would have to look like if 3-jaw chucks that >>>> could take any size were not in widespread use. Note that there >>>> are very small ones and very big ones and ones in between. Then >>>> think about how such a thing would be made. Then think about why >>>> anybody in his right mind would make them that way if there was >>>> another option. Then tell us whether you still think that the >>>> existence of 3-jaw chucks has anything to do with metric vs inch. >>>> >>>> You usually come across as a very sensible person but on this >>>> particular issue you're way off base. >>>> >>>> >>> I'm thinking about how drills changed over the years _before_ >>> electricity. I don't remember ever seeing hand drills with >>> the option of changing the bits. Do you know the ones I'm >>> talking about? You held the shaft with both hands and rotated; >>> the shaft looked like a step-function graph. >> >> Carpenters's brace-and-bit, which used a square taper shank. So >> happens that the two-jaw chuck for those was developed about the >> same time as the three-jaw chuck for round bits in the late 1800s. >> Prior to that time a square hole was used for the square taper >> shanks and collets for the round bits. Neither had anything to do >> with the introduction of the metric system. > > Kewl. Thanks. I'm haven't said that it has to do with the intro > of the metric system. I was trying to talk about why a drill > was designed to accept all sizes of bits. Read ^my line^ about > adapting to any system: US, si or Sears. I was support the > comment. Right after that someone disagreed. > > I think there is a passing of missed understandings here. > > >> >> Just as an example, a starter set of drill bits for someone taking up >> machining in the US will have 115 bits ranging in diameter from >> 0.04" up to >> 0.5". Any drill that will take all those bits will also take any >> metric bit from 1mm to 12.5mm. Drills smaller than 1/4 inch or so >> with square tapered shanks are rare--you won't find any in such a >> set no matter how old it is. What you will find is a round taper, >> called a Morse taper, that was developed in the US in the 1860s and >> is now subject of an ISO standard and still in widespread use. The >> taper can be used directly to mount tooling, but more commonly is >> used to mount a chuck. >> >> Further, the fact that a country is metric doesn't mean that all >> drill bits used for machining come in even fractions of a >> millimeter. For example to get a close clearance fit on a shaft >> that is 10mm +/- .0001, you'd need to a hole that is between 10.013 >> and 10.055 mm diameter, or nominally 10.034mm. >> >> This is the nature of drilling and the reason that drills can take >> bits of many sizes. >> >> By the way, power drills were in use long before electricity--they >> ran on steam or water power. >> > > Those power drills had to be stationary. How would you design a > portable power drill that ran on water power? You didn't, you took the work to the drill, not the drill to the work. Things that we currently do with power drills used to be done with bow drills that got replaced with geared hand-cranked drills, for larger holes with a brace and bit, and for holes too big for a brace and bit with a two-handed auger (generally the drill and bit were one piece with a hole through the shank through which one passed a wooden handle). Precision drilling is still for the most part done with stationary tools--getting accurate placement and angular alignment with a hand-held drill is difficult even with jigs.
From: Andrew Usher on 17 Feb 2010 20:40
Darwin123 wrote: > I was making an analogy between you and Adolf Hitler in terms of > irrationality. I wasn't calling you a killer or anything. I think that sort of analogy is a real stretch. > My analogy is based on the fact that your objections are based > solely on political ideology. You apparently have no idea how > standards work in an actual machine shop, or in a laboratory. Your > main objection is that it is an example of "white-guilt." My objections are not solely based on politics; I think I made that clear. > This is the first time that i have heard "white-guilt" and > colonialism tied to the metric system. You made vague references to > the French Revolution. I hypothesize that you associate the French > Revolution with the metric system. My conjecture is that since the > French Republic degenerated into a system vaguely like Communism, you > associate the metric system with Communism. When thI may be wrong, but > there is no other connection between the metric system and the left > that I can think of. I actually praise the French revolution in general, and call myself a socialist. You would know this if you'd read many of my posts. Andrew Usher |