Actually, the correct terminology is Imperial units, not English. And mils is actually a unit of angle.
the correct terminology for 1/1000 of an inch is thousandth or thou. On Thu, Jul 9, 2009 at 1:30 PM, Dan <dan...@wolstenholme.net> wrote: > > > Not true. I'm an American engineer, and I prefer English units for certain > applications (and metric for others). > > 1) The proper name is English units. It has nothing to do with the present > practices of England, the country; that's where they originated from, so > that's what they're called. They're not "Roman" units (how ridiculous), > because the Romans didn't have "inches". This is just like how the English > language is called "English", even though the way it's spoken in places like > the USA and India is very, very different from the way it's spoken in > England presently. > > 2) English units are more convenient for some things, such as temperature > (when relating to humans, like for setting your thermostat, not when doing > calculations in a lab). The Fahrenheit scale is better scaled for the human > range of temperature, and doesn't require messing with fractional units the > way Celcius does. The Fahrenheit thermostats in our homes are in whole > degrees only, because a half-degree of precision is pointless in Fahrenheit > since humans can't really tell the difference. But half-degrees in Celcius > thermostats are necessary because humans certainly can tell the difference > there (being about equivalent to a whole Fahrenheit degree). > > 3) It's funny how UK residents like to claim they don't use English units > any more, when in fact they do: the talk about speed in miles per hour, and > they order beer in pints, and they relate their body weight in "stones" > (whatever those are), not kilos. > > This isn't much different than the USA, where people's speedometers are in > MPH, their weight in pounds, etc., but when they go into a science lab, > everything is in metric. Metric proponents talk about how useful it is to be > able to convert between units so easily with metric, like converting kilos > and meters to Newtons or whatever, but what they're missing is that most > people don't do this! No one is going to step on the scale, read their > weight, and then need to convert that into a torque or force. No one wants > to read their home temperature on their thermostat and then calculate > thermal energy. > > There's a big difference between what regular people do in their daily > lives, and what scientists and engineers do for work. That's why even here > in the USA, most scientists and engineers (esp. scientists) work with metric > units at work, and then go home and set their thermostat in Fahrenheit and > read their weight in pounds, and don't have a big problem with this > discrepancy. > > 4) Inches (or more importantly, mils) are still pretty useful in PCB > design. It's easy to remember things like 8 mil minimum track width, 20 mil > track-to-board-edge spacing, etc. Also, many many components are designed in > mils: most chips have pin spacing in mils: 100 mils for DIP chips, 50 mils > for SOIC, 25 mils for TQFP, etc. > > However, more and more components are showing up in metric, and that is > annoying with Kicad since it doesn't have hard metric; instead of .1mm > spacing, I have to choose .1056644353 or whatever. This really needs to be > fixed; I should be able to lay out a PCB with both English and metric > components without so much slop on the metric ones. Why does Kicad even have > this soft-metric thing? If I want English, I'll select English. If I select > mm, that means I'm working with a part designed in metric, and I need > metric. > > Dan > > --- In kicad-users@yahoogroups.com <kicad-users%40yahoogroups.com>, al > davis <a...@...> wrote: > > > > On Thursday 09 July 2009, Robert wrote: > > > America is the last country > > > in the world where engineers prefer to use them. > > > > American engineers don't prefer traditional units. It's the > > non-engineers. > > > > > -- IBA #15631
