Physix side-step (was Re: most useful math for DSP)
robert bristow-johnson
in deja so this won't thread right.
Grant Griffin <grant....@iowegian.com> wrote:
> >
> > You know, Clay, these physical constant things really bug me. Now, "pi"
> > and "e"...well, now you've really got something. But these physical
> > constant thingies: let's face it, they're just fudge factors consisting
> > of a number, along with whatever units are required to make the equation
> > balance.
actually there are a few physical constants that are dimensionless
and therefore cannot be changed numerically if you convert to a
different set of units. one common one is the ratio of a proton
mass to an electron mass which is, i believe, the same here as it
is on the planet Alderon (long ago, in a galaxy far away). another
is the Fine-structure constant (= 1/137.036).
these numbers are as ponderable as are pi and e and Euler's
constant or whatever.
In article <3821A832...@wybron.com>,
emcb...@wybron.com wrote:
> Agreed. If you choose units for that purpose, the speed of light is
> unity. And so can any other "physical constant" be made equal to unity
> or whatever you want it to be.
...
>
well, long ago, when i was in college, i was intrigued about the
concept of "universal" physical constants and if we could describe
them with a "universal" set of physical units that didn't depend
on 10^7 meters between the north pole and the equator on a great
circle going through Paris, or the second, or even the density of
water (if you're from the planet Zork, what the hell is so special
about water?).
anyway the propositions that this system of measurement would
be based on is that there would be a unit time, length, mass,
and electric charge so that when you toss them together in
fundamental physical equations, that known universal physical
quantities would come out equaling exactly one unit.
so here's how it went:
we have a unit time, T; a unit length L; a unit mass, M; and a
unit charge, Q.
we know the speed of light, c; Planck's constant, h_bar; and
the gravitational constant, G. the Coulomb electric force
constant is actually not an independent physical quantity but
depends directly on the speed of light, c, and the magnetic
force constant, u0, which is _defined_ not measured. so
given c, we don't need to mess with any k or epsilon0.
we define the unit speed
L/T = c
and the unit energy, E to be:
E = M*c^2 = h_bar/T = G*M^2/L = 1/(4*pi*epsilon0)*Q^2/L = u0/(4*pi)*c^2*Q^2/L
i came up with:
T = sqrt(G*h_bar/c^5) = 5.38956e-44 s
L = sqrt(G*h_bar/c^3) = 1.61575e-35 m
M = sqrt(c*h_bar/G) = 2.17716e-08 kg
Q = sqrt((4*pi/u0)*h_bar/c) = 1.87556e-18 co
E = sqrt(c^5*h_bar/G) = 1.95673e+09 J
given boltzman's constant, the unit temp was even more impractical
(like about 10^32 degrees K).
so this all turned out to be pretty useless (but recreational)
however, the charge of the electron measured in units of Q above
came out to be the sqrt of the Fine-structure constant.
so next time anybody has their thumb up their butt meditating on
the digits of pi or e, they should consider 137.0360123... i
wonder what God had in mind about that number. also, how
different life might be if it were different.
--
r b-j
pbj...@viconet.com a.k.a. rob...@audioheads.com
a.k.a. rob...@wavemechanics.com
"Don't give in to the Dark Side. Boycott intel and microsoft."
Robert Bielik
> and therefore cannot be changed numerically if you convert to a
> different set of units. one common one is the ratio of a proton
> mass to an electron mass which is, i believe, the same here as it
> is on the planet Alderon (long ago, in a galaxy far away).
Not necessarily... (see http://www.energyscience.co.uk). Sorry, couldn't
resist... :-)
/Rob
"People see things that are and ask - Why?
I see things that never were and ask - Why not?"
G.B.Shaw
Clay S. Turner
>
> this thread missed my newserver completely but i stumbled upon it
> in deja so this won't thread right.
>
> Grant Griffin <grant....@iowegian.com> wrote:
> > >
> > > You know, Clay, these physical constant things really bug me. Now, "pi"
> > > and "e"...well, now you've really got something. But these physical
> > > constant thingies: let's face it, they're just fudge factors consisting
> > > of a number, along with whatever units are required to make the equation
> > > balance.
>
> and therefore cannot be changed numerically if you convert to a
> different set of units. one common one is the ratio of a proton
> mass to an electron mass which is, i believe, the same here as it
Actually Robert,
These quantities known as Planck units i.e., Planck mass, Planck
length, etc. are much more than recreational musings. In 1899, Planck
realized the implications of his newly found constant, and he thus
formulated what we now call the Planck scale. Many view quantum field
theory as functioning on all scales i.e., the space time continuum
exists down to infinitely small distances, times etc., but experience
indicates otherwise. When quantities are of the order of the Planck
scale, many difficulties appear in quantum field theories. So there is
much to learn about the space time continuum on the order of the Planck
scale.
Clay S. Turner
Grant Griffin
>
> this thread missed my newserver completely but i stumbled upon it
> in deja so this won't thread right.
>
> Grant Griffin <grant....@iowegian.com> wrote:
> > >
> > > You know, Clay, these physical constant things really bug me. Now, "pi"
> > > and "e"...well, now you've really got something. But these physical
> > > constant thingies: let's face it, they're just fudge factors consisting
> > > of a number, along with whatever units are required to make the equation
> > > balance.
>
> actually there are a few physical constants that are dimensionless
> and therefore cannot be changed numerically if you convert to a
> different set of units. one common one is the ratio of a proton
> mass to an electron mass which is, i believe, the same here as it
> is on the planet Alderon (long ago, in a galaxy far away). another
> is the Fine-structure constant (= 1/137.036).
>
> these numbers are as ponderable as are pi and e and Euler's
> constant or whatever.
>
I hadn't pondered that. But it still bugs me that one must measure
stuff to come up with the number whereas pi and e can be created from
whole cloth.
> In article <3821A832...@wybron.com>,
> emcb...@wybron.com wrote:
>
> > Agreed. If you choose units for that purpose, the speed of light is
> > unity. And so can any other "physical constant" be made equal to unity
> > or whatever you want it to be.
> ...
> >
>
> well, long ago, when i was in college, i was intrigued about the
> concept of "universal" physical constants and if we could describe
> them with a "universal" set of physical units that didn't depend
> on 10^7 meters between the north pole and the equator on a great
> circle going through Paris, or the second, or even the density of
> water (if you're from the planet Zork, what the hell is so special
> about water?).
You know...I've been hatching a theory lately that the metric system has
not been accepted in America largely because it lacks anything
resembling a foot. The basic unit of the metric system, the yard, is
useful mainly for measuring football fields; don't try to build your
house with it. Likewise, the centimeter isn't very servicible until you
stack 2.54 of them together. I therefore contend that the metric system
would have been much more widely accepted (in America, at least) if the
whole thing had been based on the foot. (Scientists could count
wavelengths or whatever to exactly define a foot if that provides them
with employment: kindda reminds me of that old Ernie Kovacs sketch where
he's trying to count gumballs in a fishbowl to win a prize.)
That being said, my proposed revision of the metric system would likely
disrupt one of the good things one can say about it: the fact that
everything seems to be related to the much-more-servicable English
system by about a factor of two. An inch is about 2 centimeters; a mile
is about 2 kilometers; a gallon is about two liters. However, this
brings us to a very noticible non-uniformity in the "uniform" (read:
anal retentive) metric system: a meter is either about one yard or about
three feet. So much for uniformity. No wonder practical people find
the metric system so hard to learn.
=g2
--
_____________________________________________________________________
Grant R. Griffin g...@dspguru.com
Publisher of dspGuru http://www.dspguru.com
Iowegian International Corporation http://www.iowegian.com
Jerry Avins
>
...
>
> That being said, my proposed revision of the metric system would likely
> disrupt one of the good things one can say about it: the fact that
> everything seems to be related to the much-more-servicable English
> system by about a factor of two. An inch is about 2 centimeters; a mile
> is about 2 kilometers; a gallon is about two liters. However, this
> brings us to a very noticible non-uniformity in the "uniform" (read:
> anal retentive) metric system: a meter is either about one yard or about
> three feet. So much for uniformity. No wonder practical people find
> the metric system so hard to learn.
Is this tongue-in-cheek, or foot-in-mouth? For inches, I'll buy that 2
1/2 is close enough to 2 to avoid a quibble, but a liter (or a litre,
as the British call it) is a shade over a quart. (1.057 = 1 + shade.)
At least a metre is no longer 1/10,000 of the distance from the North
Pole to the Equator on an arc passing through Paris!
>
> =g2
> --
> _____________________________________________________________________
>
> Grant R. Griffin g...@dspguru.com
> Publisher of dspGuru http://www.dspguru.com
> Iowegian International Corporation http://www.iowegian.com
Jerry
--
Engineering is the art of making what you want from things you can
get.
-----------------------------------------------------------------------
Grant Griffin
>
> Grant Griffin wrote:
> >
> ...
> >
> > That being said, my proposed revision of the metric system would likely
> > disrupt one of the good things one can say about it: the fact that
> > everything seems to be related to the much-more-servicable English
> > system by about a factor of two. An inch is about 2 centimeters; a mile
> > is about 2 kilometers; a gallon is about two liters. However, this
> > brings us to a very noticible non-uniformity in the "uniform" (read:
> > anal retentive) metric system: a meter is either about one yard or about
> > three feet. So much for uniformity. No wonder practical people find
> > the metric system so hard to learn.
>
> Is this tongue-in-cheek, or foot-in-mouth?
(take a guess. :-)
> For inches, I'll buy that 2
> 1/2 is close enough to 2 to avoid a quibble, but a liter (or a litre,
> as the British call it) is a shade over a quart. (1.057 = 1 + shade.)
Are you saying that they actually used _two_ factors of two?
> At least a metre is no longer 1/10,000 of the distance from the North
> Pole to the Equator on an arc passing through Paris!
BTW, if this was the original basis of the metric system, it goes a long
way to explaining why the thing ended up with the yard as the basic unit
of measure. (What planet were these guys living on?)
Jerry Avins
Grant Griffin wrote:
>
> Jerry Avins wrote:
...
>
> > For inches, I'll buy that 2
> > 1/2 is close enough to 2 to avoid a quibble, but a liter (or a litre,
> > as the British call it) is a shade over a quart. (1.057 = 1 + shade.)
>
> Are you saying that they actually used _two_ factors of two?
>
> > At least a metre is no longer 1/10,000 of the distance from the North
> > Pole to the Equator on an arc passing through Paris!
>
> BTW, if this was the original basis of the metric system, it goes a long
> way to explaining why the thing ended up with the yard as the basic unit
> of measure. (What planet were these guys living on?)
>
> =g2
Judging from the houses around here, some yards are bigger than
others.
Phil Martel
Jerry Avins <j...@ieee.org> wrote in message
news:3829002F...@ieee.org...
> Grant Griffin wrote:
> >
> ...
> >
> > That being said, my proposed revision of the metric system would likely
> > disrupt one of the good things one can say about it: the fact that
> > everything seems to be related to the much-more-servicable English
> > system by about a factor of two. An inch is about 2 centimeters; a mile
> > is about 2 kilometers; a gallon is about two liters. However, this
> > brings us to a very noticible non-uniformity in the "uniform" (read:
> > anal retentive) metric system: a meter is either about one yard or about
> > three feet. So much for uniformity. No wonder practical people find
> > the metric system so hard to learn.
>
> 1/2 is close enough to 2 to avoid a quibble, but a liter (or a litre,
> as the British call it) is a shade over a quart. (1.057 = 1 + shade.)
> Pole to the Equator on an arc passing through Paris!
Hmmm, perhaps you mean 1/10,000,000??
Best wishes,
--Phil Martel
> >
> > =g2
> > --
> > _____________________________________________________________________
> >
> > Grant R. Griffin g...@dspguru.com
> > Publisher of dspGuru http://www.dspguru.com
> > Iowegian International Corporation http://www.iowegian.com
>
Grant Griffin
>
> Grant Griffin wrote:
> >
> > Jerry Avins wrote:
> ...
> >
> > > 1/2 is close enough to 2 to avoid a quibble, but a liter (or a litre,
> > > as the British call it) is a shade over a quart. (1.057 = 1 + shade.)
> >
> >
> > > Pole to the Equator on an arc passing through Paris!
> >
> > way to explaining why the thing ended up with the yard as the basic unit
> > of measure. (What planet were these guys living on?)
> >
> > =g2
>
> Judging from the houses around here, some yards are bigger than
> others.
>
Even the yards with adobe houses?
Grant Griffin
>
> Jerry Avins <j...@ieee.org> wrote in message
> news:3829002F...@ieee.org...
> > Grant Griffin wrote:
> > >
> > ...
> > >
> > > That being said, my proposed revision of the metric system would likely
> > > disrupt one of the good things one can say about it: the fact that
> > > everything seems to be related to the much-more-servicable English
> > > system by about a factor of two. An inch is about 2 centimeters; a mile
> > > is about 2 kilometers; a gallon is about two liters. However, this
> > > brings us to a very noticible non-uniformity in the "uniform" (read:
> > > anal retentive) metric system: a meter is either about one yard or about
> > > three feet. So much for uniformity. No wonder practical people find
> > > the metric system so hard to learn.
> >
> > 1/2 is close enough to 2 to avoid a quibble, but a liter (or a litre,
> > as the British call it) is a shade over a quart. (1.057 = 1 + shade.)
> > Pole to the Equator on an arc passing through Paris!
>
>
See there, Jerry, using only factors of ten really doesn't help much...
Jerry Avins
>
> Jerry Avins <j...@ieee.org> wrote in message
> news:3829002F...@ieee.org...
> > Grant Griffin wrote:
> > >
> > ...
> > >
> > > That being said, my proposed revision of the metric system would likely
> > > disrupt one of the good things one can say about it: the fact that
> > > everything seems to be related to the much-more-servicable English
> > > system by about a factor of two. An inch is about 2 centimeters; a mile
> > > is about 2 kilometers; a gallon is about two liters. However, this
> > > brings us to a very noticible non-uniformity in the "uniform" (read:
> > > anal retentive) metric system: a meter is either about one yard or about
> > > three feet. So much for uniformity. No wonder practical people find
> > > the metric system so hard to learn.
> >
> > Is this tongue-in-cheek, or foot-in-mouth? For inches, I'll buy that 2
> > 1/2 is close enough to 2 to avoid a quibble, but a liter (or a litre,
> > as the British call it) is a shade over a quart. (1.057 = 1 + shade.)
> > At least a metre is no longer 1/10,000 of the distance from the North
> > Pole to the Equator on an arc passing through Paris!
>
> Hmmm, perhaps you mean 1/10,000,000??
>
> --Phil Martel
In my snooty way, I go around telling people who say "You know what I
mean ..." "Not really, I only know what you say." Hoist by my own
petard! (I was thinking in kilometers, writing in meters.)
Mike Percy
>
> Jerry Avins <j...@ieee.org> wrote in message
> news:3829002F...@ieee.org...
> > Grant Griffin wrote:
> > >
[metric system joke?]
Long distances and speeds I still have to convert mentally to miles and mph, and
knowing some key numbers, like 10k == 6.2 miles and 55mph == 88kph helps. But
thanks to 2 liter bottles of Coke, .5 liter bottles of water, 750ml wine
bottles, metric socket wrenches, etc. I (and I hope America in general) are
getting used to metric measurements. Those metric soket wrenches make me think
everytime how stupid English system is: all the English sockets are in
fractions, and of course are simplified 1/16, 3/32, 1/8, ... Finding the next
size larger or smaller requires doing fractions in my head (ouch) because I
can't keep my sockets in ascending order all the time. If I've got a 6mm socket
and it's a smidge too big, I know the next size up is 7mm.
BTW, I read that the Space Station has a mix of metric and english parts -- hate
to be the astronaut who goes EVA with the 9/16ths wrench when he needed the
14mm.
--
"I don't know about your brain, but mine is really...bossy."
Mike Percy, Senior Computer Scientist, Scientific Research Corp.
Ralph Weir
up is 7mm.
Er - 6.5mm. Sorry! It's the next one in the row... oh no I've dropped the
socket set and they're all muddled... (been there, done that!)
There was a horrible time in the UK when everything was switching over to
metric - so if you bought a Ford car with an engine built in the UK, gearbox
built in France and all screwed together in Germany... you ended up with a
lot of nuts with rounded corners because you ALWAYS brought the metric
spanner when you needed the Imperial version, or vice versa...
ATB
R
Mike Percy wrote in message <382AE8FC...@scires.com>...
Clay S. Turner
>
> Phil Martel wrote:
> >
> > Jerry Avins <j...@ieee.org> wrote in message
> > news:3829002F...@ieee.org...
> > > Grant Griffin wrote:
> > > >
>
> [metric system joke?]
Don't forget that if a dollar is a mile, then the U.S. public debt is a
light year!
Clay
Grant Griffin
>
> Phil Martel wrote:
> >
> > Jerry Avins <j...@ieee.org> wrote in message
> > news:3829002F...@ieee.org...
> > > Grant Griffin wrote:
> > > >
>
> [metric system joke?]
>
> knowing some key numbers, like 10k == 6.2 miles and 55mph == 88kph helps. But
> thanks to 2 liter bottles of Coke, .5 liter bottles of water, 750ml wine
> bottles, metric socket wrenches, etc. I (and I hope America in general) are
> getting used to metric measurements.
I'm not sure we ever will.
Sure, that whole nutty thing about powers of ten is pretty cool, but the
sizes of the units themselves are so un-servicable. Americans are a
practical people.
> Those metric soket wrenches make me think
> everytime how stupid English system is: all the English sockets are in
> fractions, and of course are simplified 1/16, 3/32, 1/8, ...
BTW, is there any good reason why the stock market still trades in
eigths? And is there any compelling reason that changes in the market
indices are reported in "points" rather than percentage terms? And does
a Dow of 10,000+ really need to be reported to two digits of accuracy
past the decimal point? (Metric fans: help me out here.)
> Finding the next
> size larger or smaller requires doing fractions in my head (ouch)
Not to brag, but I've nearly got them memorized.
> because I
> can't keep my sockets in ascending order all the time. If I've got a 6mm socket
> and it's a smidge too big, I know the next size up is 7mm.
If I've got a 6mm socket and it's a smidge too big, I know that I need
an English socket.
>
> BTW, I read that the Space Station has a mix of metric and english parts
OK, even _I_ think this is a really dumb idea (particularly in light of
recent events.) Then again, maybe it's easier to build Space Stations
in terms of feet than yards.
> -- hate
> to be the astronaut who goes EVA with the 9/16ths wrench when he needed the
> 14mm.
or 15mm.
>
> --
> "I don't know about your brain, but mine is really...bossy."
> Mike Percy, Senior Computer Scientist, Scientific Research Corp.
If you think _yours_ is bad... ;-)
Grant Griffin
>
> Mike Percy wrote:
> >
> > Phil Martel wrote:
> > >
> > > Jerry Avins <j...@ieee.org> wrote in message
> > > news:3829002F...@ieee.org...
> > > > Grant Griffin wrote:
> > > > >
> >
> > [metric system joke?]
>
> light year!
>
> Clay
>
Are you suggesting, Clay, that there's an inherent physical limit to how
fast government can pile on debt? Now I understand why we have a
so-called "balanced budget": the politicians couldn't help it. And now
that I think about it, time dilation goes a long way towards explaining
why Jesse Helms and Strom Thurmund are still in office.
Jerry Avins
>
> Phil Martel wrote:
> >
> > Jerry Avins <j...@ieee.org> wrote in message
> > news:3829002F...@ieee.org...
> > > Grant Griffin wrote:
> > > >
>
> [metric system joke?]
>
> knowing some key numbers, like 10k == 6.2 miles and 55mph == 88kph helps. But
> thanks to 2 liter bottles of Coke, .5 liter bottles of water, 750ml wine
> bottles, metric socket wrenches, etc. I (and I hope America in general) are
> everytime how stupid English system is: all the English sockets are in
> size larger or smaller requires doing fractions in my head (ouch) because I
> can't keep my sockets in ascending order all the time. If I've got a 6mm socket
> and it's a smidge too big, I know the next size up is 7mm.
>
> to be the astronaut who goes EVA with the 9/16ths wrench when he needed the
> 14mm.
>
> "I don't know about your brain, but mine is really...bossy."
> Mike Percy, Senior Computer Scientist, Scientific Research Corp.
I keep a full set of sockets and other wrenches in my car. Now, I need
both American* and metric, and I worry about a hernia every time I
lift my tool box.
*English wrenches are different. Back before they went metric, their
wrenches had the same markings as ours, but they didn't fit our nuts.
An American wrench is enough oversize to fit on a standard tolerance
nominal nut. An English spanner is nominal, and the nut is enough
undersize to allow for both tolerances. Something like that, anyhow.
There were other idiocies in those days. French metric nuts wouldn't
fit German metric bolts if the same nominal size; the thread forms
were different. German, French, and British thread forms were
different - the British had several different ones - and some Swiss
sizes used the French form, some the German. Many of these thread
forms needed a different lathe tool to cut each pitch because they had
pitch-dependent radii. (The French form came to a point.) Finally,
when the Common Market forced standardization, they all adopted the
American form. It has an easily measured angle - 60° - and flats,
making a single tool suitable for a large range of sizes.
Most "metric" sockets used throughout the world fit American (1/2,
3/8. and 1/4 inch) drivers. American Spark plugs have always been
metric. The sizes are such that there is both an American and a metric
wrench to fit each. Before they went metric, the British needed
special spark plug wrenches. And on, and on!
Jerry Avins
Mike Percy wrote:
>
...
>
> BTW, I read that the Space Station has a mix of metric and english parts -- hate
> to be the astronaut who goes EVA with the 9/16ths wrench when he needed the
> 14mm.
>
> --
> "I don't know about your brain, but mine is really...bossy."
> Mike Percy, Senior Computer Scientist, Scientific Research Corp.
One time one of my colleagues disassembled the German mass
spectrometer attached to his vacuum system before reading
_all_of_the_instructions_. A part of it used a steel ball as a thrust
bearing, and the fine print said NEVER to reuse the ball; replace it
with a new one. Size: 6.35 mm. He just about went nuts trying to find
one, calling several vendors and manufacturers. None carried or
produced metric sizes. (At that time, and still for all I know, all
bearings, metric and English, used English-size balls in the races.)
After a couple of days of frantic search, one of the purchasing agents
suggest that he consult the repository of arcane information and odd
parts — me. "Sure", I said. "I'll bring some right over." I went to
the stockroom — there was a box with a few hundred 1/4" balls — and
took a few up to his lab. He whipped out his metric micrometer, and
sure enough, 6.35 mm. on the nose. "Holy Sh?t! Where did you get them?
"The stockroom has a box full." That's when I heard his sad story.
Jim Carr
>>
>> Phil Martel wrote:
>> >
>> > Jerry Avins <j...@ieee.org> wrote in message
>> > news:3829002F...@ieee.org...
>> > > Grant Griffin wrote:
>> > > >
>>
>> [metric system joke?]
>>
} Long distances and speeds I still have to convert mentally to miles and mph, and
} knowing some key numbers, like 10k == 6.2 miles and 55mph == 88kph helps. But
} thanks to 2 liter bottles of Coke, .5 liter bottles of water, 750ml wine
} bottles, metric socket wrenches, etc. I (and I hope America in general) are
} getting used to metric measurements.
In article <382B3A...@iowegian.com>
grant....@iowegian.com writes:
>
>I'm not sure we ever will.
Like most people even look at their speedometers. They would be
just as happy with road signs that said "Foobar City, about 1 hour".
>Sure, that whole nutty thing about powers of ten is pretty cool, but the
>sizes of the units themselves are so un-servicable.
List your examples, since you had no objection to the already-adopted
liter and km ones. My pace is closer to a meter than a foot, so a
meter is hardly "un-servicable". Kilogram? Adopt that and everyone
will have lost weight but complain that meat costs more.
--
James A. Carr <j...@scri.fsu.edu> | Commercial e-mail is _NOT_
http://www.scri.fsu.edu/~jac/ | desired to this or any address
Supercomputer Computations Res. Inst. | that resolves to my account
Florida State, Tallahassee FL 32306 | for any reason at any time.
Jim Carr
>
>BTW, I read that the Space Station has a mix of metric and english parts --
>hate to be the astronaut who goes EVA with the 9/16ths wrench when he needed
>the 14mm.
My dad recently sent me the joke about how one dimension of the space
shuttle was indirectly determined by the width of a horse's ass in
ancient Rome. One of the classics.
Note followups.
Jim Carr
>
>Are you suggesting, Clay, that there's an inherent physical limit to how
>fast government can pile on debt?
Look at WW II and you will see an example of how fast government can
borrow money. That special case was at about 50% of GDP per year.
And discuss it in sci.econ or talk.politics where it belongs.
J. Wesley Cleveland
Grant Griffin wrote:
>
>
> BTW, is there any good reason why the stock market still trades in
> eigths?
A very good reason. Brokers make money on the spread. If it could be
smaller than an eighth, they wouldn't make as much.
Bob White
'metric system.' Has anyone yet pointed out that the Imperial system is a
binary system? 2 pints to a quart, etc. Some of the powers of 2 have
fallen out of common usage, but I'm told that there are actually names for
each time the measure is doubled. Fractional measure is also binary (1/2
1/4 1/8 1/16, etc.)
The best argument I have yet heard for the Imperial system is this. Take a
pile of sand. Divide it into two equal piles, again and again. It is quite
easy to do this accurately, by inspection. Now take a pile of sand and try
to divide it into ten equal parts!
Not to mention the metric bolts, where to get to reasonable variations in
sizes they use things like 6.5mm, etc. The USS and SAE bolts have very
useful changes in size from one size to the next.
I suspect that the metric system stems from one of two sources,
1. Pedants who have never built anything, but know how to multiply by 10,
or
2. The French, who have to do it their way just to be different.
just my 6.35 cents worth.
Bob
Jim Carr
... note followups ...
In article <fSYW3.7096$Ti4.7...@alfalfa.thegrid.net>
"Bob White" <b...@whitek.com> writes:
>
>I just noticed this thread, and it sparks one of my biggest gripes, the
>'metric system.' Has anyone yet pointed out that the Imperial system is a
>binary system? 2 pints to a quart, etc.
You sure stopped quickly.
You mean like 3 teaspoons in a tablespoon (blew out one contestant
on SYWTBAM)? 5280 feet in mile? 16.5 feet in a rod? 12 inches in
foot? 3 feet in a yard? 3 scruples in a dram (Apoth)?
>Some of the powers of 2 have
>fallen out of common usage, but I'm told that there are actually names for
>each time the measure is doubled.
They just aren't the same if you are measuring water or strawberries.
28.875 in^3 in a pint? Unless it is a dry pint, which is 33.60 in^3?
>The best argument I have yet heard for the Imperial system is this. Take a
>pile of sand. Divide it into two equal piles, again and again. It is quite
>easy to do this accurately, by inspection. Now take a pile of sand and try
>to divide it into ten equal parts!
So how is that a good argument for 20 grains in a scruple?
Gregory L. Hansen
Bob White <b...@whitek.com> wrote:
>I just noticed this thread, and it sparks one of my biggest gripes, the
>'metric system.' Has anyone yet pointed out that the Imperial system is a
>fallen out of common usage, but I'm told that there are actually names for
>1/4 1/8 1/16, etc.)
>
>pile of sand. Divide it into two equal piles, again and again. It is quite
>easy to do this accurately, by inspection. Now take a pile of sand and try
>to divide it into ten equal parts!
Is this a problem you often encounter? It doesn't seem very useful unless
you start with, say, exactly a jigger of sand. What happens if you start
with one and three-fourths jiggers? Dividing by two isn't very hard,
anyway.
>Not to mention the metric bolts, where to get to reasonable variations in
>sizes they use things like 6.5mm, etc. The USS and SAE bolts have very
>useful changes in size from one size to the next.
You can't seriously be using bolts as an example of the imperial system
making more sense! What's the diameter of a #8 bolt? What's the diameter
of a #6? What drill bit makes a clearance hole for a #8 bolt (it's not
a #8 bit). What's the diameter of a #B drill bit? What's the diameter of
a 1/4" NPT nipple? Hint, nothing about it has anything to do with 1/4".
Gah! At least with metric I'll know I can use a 6.5mm bit to drill a
clearance hole for a 6.5mm screw. Ask me what the diameter of a 12mm
drill bit is. Go on, ask me. Now tell me what letter is a 1/2" drill
bit.
I'm reminded of a friend trying to convince a fellow student and me that
inches are better than centimeters, then he looked for a calculator to
convert the fraction of an inch to the decimal equivalent.
>I suspect that the metric system stems from one of two sources,
>1. Pedants who have never built anything, but know how to multiply by 10,
How can you say with a straight face that the imperial system is better in
the shop? Does it really increase your workload that much to utter the
two extra syllables in "6.5"? I suspect either you haven't built much, or
your dad is a machinist and has raised you on inch measurements from an
early age.
>or
> 2. The French, who have to do it their way just to be different.
That's a reasonable guess.
--
"That's not an avocado, that's a grenade!" -- The Skipper
Grant Griffin
>
> >Mike Percy wrote:
> >>
> >> Phil Martel wrote:
> >> >
> >> > Jerry Avins <j...@ieee.org> wrote in message
> >> > news:3829002F...@ieee.org...
> >> > > Grant Griffin wrote:
> >> > > >
> >>
> >> [metric system joke?]
> >>
> } Long distances and speeds I still have to convert mentally to miles and mph, and
> } knowing some key numbers, like 10k == 6.2 miles and 55mph == 88kph helps. But
> } thanks to 2 liter bottles of Coke, .5 liter bottles of water, 750ml wine
> } bottles, metric socket wrenches, etc. I (and I hope America in general) are
> } getting used to metric measurements.
>
> In article <382B3A...@iowegian.com>
> grant....@iowegian.com writes:
> >
> >I'm not sure we ever will.
>
> Like most people even look at their speedometers. They would be
> just as happy with road signs that said "Foobar City, about 1 hour".
>
> >Sure, that whole nutty thing about powers of ten is pretty cool, but the
> >sizes of the units themselves are so un-servicable.
>
> List your examples, since you had no objection to the already-adopted
> liter and km ones. My pace is closer to a meter than a foot, so a
> meter is hardly "un-servicable". Kilogram? Adopt that and everyone
> will have lost weight but complain that meat costs more.
Hey, waitaminute...if you measure in kilograms, how can you _ever_ lose
weight?! (No wonder Rotund America doesn't want to switch to the metric
system!)
Grant Griffin
>
> I just noticed this thread, and it sparks one of my biggest gripes, the
> 'metric system.' Has anyone yet pointed out that the Imperial system is a
> binary system? 2 pints to a quart, etc. Some of the powers of 2 have
> fallen out of common usage, but I'm told that there are actually names for
> each time the measure is doubled. Fractional measure is also binary (1/2
> 1/4 1/8 1/16, etc.)
>
> The best argument I have yet heard for the Imperial system is this. Take a
> pile of sand. Divide it into two equal piles, again and again. It is quite
> easy to do this accurately, by inspection. Now take a pile of sand and try
> to divide it into ten equal parts!
>
I think you're onto something, Bob. Seriously, this ties into the idea
of "servicability". If "ten" were such a servicable factor we probably
would have ten hands with ten fingers each, rather than two hands with
four fingers each, plus a total of two thumbs. (That's a whole lotta
two's...)
In looking at English units, we see integral factors that are all over
the map: 12 (= 3 * 2 * 2) inches in a foot, 3 feet in a yard, 2 pints in
a quart, 4 quarts in a gallon. But there are no 5's here--let alone
10's. And there's probably a good reason: humans can conceptualize 2,
3, and maybe even 4, but they can't conceptualize 5--let alone 10.
And don't get me started on the metric system's lack of a rule of
thumb...
Jerry Avins
Have you ever built anything in a machine shop? The machine dials are
all in mils - thousandths of an inch. It's the only practical way to
work with English units. I have seen shop micrometers 100 years old;
they are all in mils.
I have a pair of Vernier calipers with fractional inches; it's an
abomination. Can you imagine using measurements like 179/512 inch?
I prefer to work English, where a mil is a practical size. A tenth of
a mm is too coarse, and .01 mm is too fine for most work (although I
occasionally need fits in the order of .0002 inch.)
Jerry
--
Engineering is the art of making what you want from things you can
get.
-----------------------------------------------------------------------
Bob White wrote:
>
> I just noticed this thread, and it sparks one of my biggest gripes, the
> 'metric system.' Has anyone yet pointed out that the Imperial system is a
> binary system? 2 pints to a quart, etc. Some of the powers of 2 have
> fallen out of common usage, but I'm told that there are actually names for
> each time the measure is doubled. Fractional measure is also binary (1/2
> 1/4 1/8 1/16, etc.)
>
> The best argument I have yet heard for the Imperial system is this. Take a
> pile of sand. Divide it into two equal piles, again and again. It is quite
> easy to do this accurately, by inspection. Now take a pile of sand and try
> to divide it into ten equal parts!
>
> Not to mention the metric bolts, where to get to reasonable variations in
> sizes they use things like 6.5mm, etc. The USS and SAE bolts have very
> useful changes in size from one size to the next.
>
> I suspect that the metric system stems from one of two sources,
> 1. Pedants who have never built anything, but know how to multiply by 10,
> or
> 2. The French, who have to do it their way just to be different.
>
Jerry Avins
thanked me for. Ti get the diameter of a numbered SAE screw, multiply
the number by 13, then add 60. The result is the diameter in mils.
Examples. #5: 5 * 13 + 60 = 125. That's right, 1/8". #10: 10 * 13 + 60
= 190. Close enough to 3/16 for many purposes. (Use a #11 drill for
tight clearance - no formula there - or 13/64 to do it in your head.)
We Americans reckon screw threads in pitch: the number of threads in
an inch. Metric threads are reckoned in lead; the reciprocal of pitch,
or mm per turn. For american threads (and now that they have American
form, also metric) subtract the lead from the body diameter. That's
it! No complex formula at all. So to tap a 5-40, you want a hole .124
- .025, or .100. Now look up the size and take the next larger
standard drill: #38; .1015. There's no good formula for drill sizes.
Drills are stored in a holder that has the decimal sizes marked on it,
so there's no need to go for the handbook. Again: 1/4-20; .25 - .05 =
.200 tap drill (.201 is closest).
"Gregory L. Hansen" wrote:
>
[snip]
>
> You can't seriously be using bolts as an example of the imperial system
> making more sense! What's the diameter of a #8 bolt? What's the diameter
> of a #6? What drill bit makes a clearance hole for a #8 bolt (it's not
> a #8 bit). What's the diameter of a #B drill bit? What's the diameter of
> a 1/4" NPT nipple? Hint, nothing about it has anything to do with 1/4".
The inside of the pipe is 1/4 inch, with a generous allowance for
rust. The I.D. of half inch pipe is 5/8" (unless it is high pressure
pipe with a thicker wall).
> Gah! At least with metric I'll know I can use a 6.5mm bit to drill a
> clearance hole for a 6.5mm screw.
You'll need to wiggle the bit to get clearance! Use 6.6mm.
> Ask me what the diameter of a 12mm
> drill bit is. Go on, ask me. Now tell me what letter is a 1/2" drill
> bit.
Sneaky! Letter drills don't go that high. The biggest is Z; .413". (V,
.377, makes good tight clearance for 3/8.
>
> I'm reminded of a friend trying to convince a fellow student and me that
> inches are better than centimeters, then he looked for a calculator to
> convert the fraction of an inch to the decimal equivalent.
Machinists need to do that too when the they get drawings from people
like our friend Bob White.
>
[snip]
robert bristow-johnson
>
> ... note followups ...
>
> In article <fSYW3.7096$Ti4.7...@alfalfa.thegrid.net>
> "Bob White" <b...@whitek.com> writes:
> >
> >'metric system.' Has anyone yet pointed out that the Imperial system is a
> >binary system? 2 pints to a quart, etc.
>
i'll say.
> You mean like 3 teaspoons in a tablespoon (blew out one contestant
> on SYWTBAM)? 5280 feet in mile? 16.5 feet in a rod? 12 inches in
> foot? 3 feet in a yard? 3 scruples in a dram (Apoth)?
>
> >Some of the powers of 2 have
> >fallen out of common usage, but I'm told that there are actually names for
> >each time the measure is doubled.
Jim is right that there are so few differently named english units are
are power of 2 related but one point from Bob that is correct is the
subdivisions of a unit in the english system are usually powers of 2
(e.g. your socket/wrench set ... 3/8", 5/16" 11/32" ..). and he's right
about the apparent advantages of power of 2 ratios in the denominator.
anyway the root problem to the base 10 metric system is our base ten
numbering system (that i think is nearly universal to all human
cultures). it kinda makes me wish we had as many fingers as the
Simpsons, just so we sould have a base 8 (or base 16, if we count toes,
too) numbering system. it would be a hellava lot easier to convert to
and from binary, too.
so we should ditch the base 10 numbering system and compulsorily teach
base 16, ditch english and teach esparanto and use a totally phoneticly
based alphabet, ditch anything intel and adopt the PowerPC and some
sorta NExTish **NIX operating system (make sure all text uses _only_ LF
or CR), get rid of Saddam Miloshnevich (whatever) and the U.S.
republicans and elect me king of the world while we're at it.
--
r b-j
pbj...@viconet.com a.k.a. rob...@audioheads.com
a.k.a. rob...@wavemechanics.com
"Don't give in to the Dark Side. Boycott intel and microsoft."
Jim Carr
... off-topic newsgroup dropped in followups ...
Jim Carr wrote:
|
| In article <382B3A...@iowegian.com>
| grant....@iowegian.com writes:
| >Sure, that whole nutty thing about powers of ten is pretty cool, but the
| >sizes of the units themselves are so un-servicable.
|
| List your examples, since you had no objection to the already-adopted
| liter and km ones. My pace is closer to a meter than a foot, so a
| meter is hardly "un-servicable". Kilogram? Adopt that and everyone
| will have lost weight but complain that meat costs more.
In article <382C86...@iowegian.com>
grant....@iowegian.com writes:
>
>Hey, waitaminute...if you measure in kilograms, how can you _ever_ lose
>weight?! (No wonder Rotund America doesn't want to switch to the metric
>system!)
Simple. You go from weight 220 one day to only 100 the next.
Same way 'Mericans think gas is cheap in Canada: overlooking that
the price is in liters.
Now, where are your examples.
Gregory L. Hansen
Jerry Avins <jya...@erols.com> wrote:
>Here are two machine shop tip that even veteran machinists have
>thanked me for. Ti get the diameter of a numbered SAE screw, multiply
>the number by 13, then add 60. The result is the diameter in mils.
>
>Examples. #5: 5 * 13 + 60 = 125. That's right, 1/8". #10: 10 * 13 + 60
>= 190. Close enough to 3/16 for many purposes. (Use a #11 drill for
>tight clearance - no formula there - or 13/64 to do it in your head.)
That looks pretty useful. The calculation only needs to be recognizably
close to the nominal value.
>We Americans reckon screw threads in pitch: the number of threads in
>an inch. Metric threads are reckoned in lead; the reciprocal of pitch,
>or mm per turn. For american threads (and now that they have American
>form, also metric) subtract the lead from the body diameter. That's
>it! No complex formula at all. So to tap a 5-40, you want a hole .124
>- .025, or .100. Now look up the size and take the next larger
>standard drill: #38; .1015.
That could be useful, but I'm sure it will be eaiser for me to just keep
using the charts.
>There's no good formula for drill sizes.
>Drills are stored in a holder that has the decimal sizes marked on it,
>so there's no need to go for the handbook. Again: 1/4-20; .25 - .05 =
Some do. The one I use doesn't.
>"Gregory L. Hansen" wrote:
>>
>[snip]
>>
>> You can't seriously be using bolts as an example of the imperial system
>> making more sense! What's the diameter of a #8 bolt? What's the diameter
>> of a #6? What drill bit makes a clearance hole for a #8 bolt (it's not
>> a #8 bit). What's the diameter of a #B drill bit? What's the diameter of
>> a 1/4" NPT nipple? Hint, nothing about it has anything to do with 1/4".
>
>The inside of the pipe is 1/4 inch, with a generous allowance for
>rust. The I.D. of half inch pipe is 5/8" (unless it is high pressure
>pipe with a thicker wall).
Nope, the inside of the pipe is about 3/8 inch, the outside is 1/2 inch.
It's called 1/4" for historical reason -- the inside used to be 1/4 inch.
But not any more.
>> Gah! At least with metric I'll know I can use a 6.5mm bit to drill a
>> clearance hole for a 6.5mm screw.
>
>You'll need to wiggle the bit to get clearance! Use 6.6mm.
Well, yeah. But straight decimal diameter is still easier to work with.
>> Ask me what the diameter of a 12mm
>> drill bit is. Go on, ask me. Now tell me what letter is a 1/2" drill
>> bit.
>
>Sneaky! Letter drills don't go that high. The biggest is Z; .413". (V,
>.377, makes good tight clearance for 3/8.
Actually, that was less sneak and more pulling a number out of my butt. I
don't know the numbers very well.
>> I'm reminded of a friend trying to convince a fellow student and me that
>> inches are better than centimeters, then he looked for a calculator to
>> convert the fraction of an inch to the decimal equivalent.
>
>Machinists need to do that too when the they get drawings from people
>like our friend Bob White.
I've always tried to put decimal dimensions on my drawings, because I know
that's how the machines tend to be set up. The hashmarks on the milling
machine correspond to mils, not 64th's of an inch.
>Engineering is the art of making what you want from things you can
>get.
Heheh!
Phil Martel
robert bristow-johnson <pbj...@viconet.com> wrote in message
news:382DBF...@viconet.com...
<snip>
>
> so we should ditch the base 10 numbering system and compulsorily teach
> base 16, ditch english and teach esparanto and use a totally phoneticly
> based alphabet,
Best wishes,
--Phil Martel
Jerry Avins
>
> In article <382D8C5F...@ieee.org>,
> Jerry Avins <jya...@erols.com> wrote:
> >> of a #6? What drill bit makes a clearance hole for a #8 bolt (it's not
> >> a 1/4" NPT nipple? Hint, nothing about it has anything to do with 1/4".
> >
> >The inside of the pipe is 1/4 inch, with a generous allowance for
> >rust. The I.D. of half inch pipe is 5/8" (unless it is high pressure
> >pipe with a thicker wall).
>
> Nope, the inside of the pipe is about 3/8 inch, the outside is 1/2 inch.
> It's called 1/4" for historical reason -- the inside used to be 1/4 inch.
> But not any more.
Yup! the inside diameter of 1/4" pipe is about 3/8 (rust and crud
allowance again). Notice that I wrote " The I.D. of half inch pipe is
5/8 ..." Do you still disagree?
>
> >> Gah! At least with metric I'll know I can use a 6.5mm bit to drill a
> >> clearance hole for a 6.5mm screw.
> >
> >You'll need to wiggle the bit to get clearance! Use 6.6mm.
>
> Well, yeah. But straight decimal diameter is still easier to work with.
Usually, but for instance, a #6 screw is .138, as close to 9/64 as
makes no difference, so a good tap drill for a 6-32 is 1/32 smaller,
or 7/64.
>
> >> Ask me what the diameter of a 12mm
> >> drill bit is. Go on, ask me. Now tell me what letter is a 1/2" drill
> >> bit.
> >
> >Sneaky! Letter drills don't go that high. The biggest is Z; .413". (V,
> >.377, makes good tight clearance for 3/8.
>
> Actually, that was less sneak and more pulling a number out of my butt. I
> don't know the numbers very well.
I just knew it couldn't be that big. I got out my letter drills and
peeked.
>
> >> I'm reminded of a friend trying to convince a fellow student and me that
> >> inches are better than centimeters, then he looked for a calculator to
> >> convert the fraction of an inch to the decimal equivalent.
> >
> >Machinists need to do that too when the they get drawings from people
> >like our friend Bob White.
>
> I've always tried to put decimal dimensions on my drawings, because I know
> that's how the machines tend to be set up. The hashmarks on the milling
> machine correspond to mils, not 64th's of an inch.
Nobody wants it any other way.
>
> >Engineering is the art of making what you want from things you can
> >get.
>
> Heheh!
Thanks!
>
> --
> "That's not an avocado, that's a grenade!" -- The Skipper
Jerry
Jerry Avins
>
> Bob White wrote:
> >
> > I just noticed this thread, and it sparks one of my biggest gripes, the
> > 'metric system.' Has anyone yet pointed out that the Imperial system is a
> > fallen out of common usage, but I'm told that there are actually names for
> > 1/4 1/8 1/16, etc.)
> >
> > The best argument I have yet heard for the Imperial system is this. Take a
> > pile of sand. Divide it into two equal piles, again and again. It is quite
> > easy to do this accurately, by inspection. Now take a pile of sand and try
> > to divide it into ten equal parts!
> >
>
> of "servicability". If "ten" were such a servicable factor we probably
> would have ten hands with ten fingers each, rather than two hands with
> four fingers each, plus a total of two thumbs. (That's a whole lotta
> two's...)
>
> In looking at English units, we see integral factors that are all over
> the map: 12 (= 3 * 2 * 2) inches in a foot, 3 feet in a yard, 2 pints in
> a quart, 4 quarts in a gallon. But there are no 5's here--let alone
> 10's. And there's probably a good reason: humans can conceptualize 2,
> 3, and maybe even 4, but they can't conceptualize 5--let alone 10.
>
> And don't get me started on the metric system's lack of a rule of
> thumb...
>
> =g2
> --
> _____________________________________________________________________
>
> Grant R. Griffin g...@dspguru.com
> Publisher of dspGuru http://www.dspguru.com
> Iowegian International Corporation http://www.iowegian.com
Don't forget 3 * 7 * 11 = 231 cubic inches to a US gallon, not to
mention 1728 to the cubic foot. Saaay! Isn't that a typical speed for
an induction motor? If you like dry measure, go figure 33.6003 cubic
inches to the pint. I wonder what I really get when I buy a pint of
strawberries. I have long been intrigued to know that a pound of
feathers weighs more than a pound of gold. How big is a barrel?
Jerry
--
Engineering is the art of making what you want from things you can
get.
-----------------------------------------------------------------------
Jerry Avins
Surely, that should be "fonetakli baced"!
>
> Best wishes,
> --Phil Martel
J
Gregory L. Hansen
Jerry Avins <jya...@erols.com> wrote:
>"Gregory L. Hansen" wrote:
>>
>> In article <382D8C5F...@ieee.org>,
>> Jerry Avins <jya...@erols.com> wrote:
> ...
>> >> of a #6? What drill bit makes a clearance hole for a #8 bolt (it's not
>> >> What's the diameter of a #B drill bit? What's the diameter of
>> >> a 1/4" NPT nipple? Hint, nothing about it has anything to do with 1/4".
>> >
>> >The inside of the pipe is 1/4 inch, with a generous allowance for
>> >rust. The I.D. of half inch pipe is 5/8" (unless it is high pressure
>> >pipe with a thicker wall).
>>
>> Nope, the inside of the pipe is about 3/8 inch, the outside is 1/2 inch.
>> It's called 1/4" for historical reason -- the inside used to be 1/4 inch.
>> But not any more.
>
>Yup! the inside diameter of 1/4" pipe is about 3/8 (rust and crud
>allowance again). Notice that I wrote " The I.D. of half inch pipe is
>5/8 ..." Do you still disagree?
Uh... you said the ID of 1/4" pipe is 1/4", didn't you? I don't allow for
rust because I've always used brass plumbing, and I don't allow for crud
because I've only built gas handling systems. But if I were to allow for
rust and crud, I'd want to use half-inch pipe rather than 1/4" pipe that
isn't.
I'm not sure what the ID of half inch pipe is, but 5/8 is a number I could
believe in.
>> >> Gah! At least with metric I'll know I can use a 6.5mm bit to drill a
>> >> clearance hole for a 6.5mm screw.
>> >
>> >You'll need to wiggle the bit to get clearance! Use 6.6mm.
>>
>> Well, yeah. But straight decimal diameter is still easier to work with.
>
>Usually, but for instance, a #6 screw is .138, as close to 9/64 as
>makes no difference, so a good tap drill for a 6-32 is 1/32 smaller,
>or 7/64.
That has actually irked me from time to time. I mentioned before that I
use decimal measurements on my shop drawings whenever I can. But I know
stock tends to come in fractions of an inch, like 3/8" thick aluminum.
And when tolerances don't need to be tight, my CAD software would say .38
inches so I have to go back and change it to 3/8" nominal. So I use
fractions for all the nominal values and decimal for the real tolerances.
I wouldn't really mind using 1cm thick aluminum, but that's just not the
way things are done around here.
Gregory L. Hansen
Gregory L. Hansen <glha...@steel.ucs.indiana.edu> wrote:
>In article <382DF8BE...@ieee.org>,
>Jerry Avins <jya...@erols.com> wrote:
>>"Gregory L. Hansen" wrote:
>>>
>>> In article <382D8C5F...@ieee.org>,
>>> Jerry Avins <jya...@erols.com> wrote:
>> ...
>>> >> of a #6? What drill bit makes a clearance hole for a #8 bolt (it's not
>>> >> What's the diameter of a #B drill bit? What's the diameter of
>>> >> a 1/4" NPT nipple? Hint, nothing about it has anything to do with 1/4".
>>> >
>>> >The inside of the pipe is 1/4 inch, with a generous allowance for
>>> >rust. The I.D. of half inch pipe is 5/8" (unless it is high pressure
>>> >pipe with a thicker wall).
>>>
>>> Nope, the inside of the pipe is about 3/8 inch, the outside is 1/2 inch.
>>> It's called 1/4" for historical reason -- the inside used to be 1/4 inch.
>>> But not any more.
>>
>>Yup! the inside diameter of 1/4" pipe is about 3/8 (rust and crud
>>allowance again). Notice that I wrote " The I.D. of half inch pipe is
>>5/8 ..." Do you still disagree?
>
>Uh... you said the ID of 1/4" pipe is 1/4", didn't you? I don't allow for
>rust because I've always used brass plumbing, and I don't allow for crud
>because I've only built gas handling systems. But if I were to allow for
>rust and crud, I'd want to use half-inch pipe rather than 1/4" pipe that
>isn't.
Actually, I use NPT as little as possible. It's just awful! Whenever I
tighten it up a gauge winds up facing the wrong direction or the valve
handles don't line up or something. To hold truly hard vacuums I need
goop like Torr-Seal to seal it up, and once that stuff hardens it doesn't
let go. I've had 1/4" brass tubing shear off on me before the Torr-Seal
gave way, and that's after blasting it with a propane torch and ruining a
gauge in the process. I wouldn't use it at all except that a lot of the
equipment we use comes with that kind of fitting.
Herman
firken of ale in the country. While a yard of fabric in Britain is
smaller than on the continent. Also, an English foot is smaller than a
Cape Dutch foot and can anybody say off the top his/her head how many
nails there are in a chain, or links in a furlong?
More recently, Lockheed caused a multi zillion dollar satellite to crash
since they measured thrust in foot-pound and NASA in Newtons. Maybe
Lockheed measures speed in furlongs per fortnight... :-)
It's a good thing that the French invented the metric system. Viva la
difference! (or some such...)
But let's not cast any stones here (pun intended)...
Have fun,
Herman
Jerry Avins
>
...
>
> Uh... you said the ID of 1/4" pipe is 1/4", didn't you? I don't allow for
> rust because I've always used brass plumbing, and I don't allow for crud
> because I've only built gas handling systems. But if I were to allow for
> rust and crud, I'd want to use half-inch pipe rather than 1/4" pipe that
> isn't.
>
could count on at least a quarter inch unless the pipe was ready to be
scrapped. The I.D. of standard weight quarter inch pipe is about 3/8"
(actually .364) before galvanizing and before crud accumulation. This
allows the actual bore to remain at least as big as nominal for a
reasonable service life. (The O.D. is .540 for all wall thicknesses.
The I.D. of extra strong quarter inch pipe is .302 because of the
thicker wall.)
Jerry Avins
>
...
>
> tighten it up a gauge winds up facing the wrong direction or the valve
> handles don't line up or something. To hold truly hard vacuums I need
> goop like Torr-Seal to seal it up, and once that stuff hardens it doesn't
> let go. I've had 1/4" brass tubing shear off on me before the Torr-Seal
> gave way, and that's after blasting it with a propane torch and ruining a
> gauge in the process. I wouldn't use it at all except that a lot of the
> equipment we use comes with that kind of fitting.
Torr-Seal is a high temperature epoxy; what did you expect? I've had
good luck with Teflon tape in gauge threads, but you need to keep it
to only a hair over one full wrap. If it's on right, you can still
turn the gauge a quarter turn by hand. Tightening it till it won't bo
nay more without breaking will often expand the female thread and
almost always guarantee a leak. All my thermocouple gauges went in
that way (1/8" NPT and my Bourdon 1/4" NPT) tubes also. I could screw
any of them out without a wrench, and none of them leaked. If you must
use gunk in the joints, use Apeizon (H?) or something similar.
I like to build vacuum systems with copper pipe. You can sweat the
permanent parts, and make flanges to sweat onto what may need to come
apart. (I use flanges to put all the two inch lines together. I make
them of aluminum, and copper plate the areas to be soldered, or the
whole thing if that's cheaper. (Nickel works too, with the right
flux.) You can buy stainless flanges from Varian. Nickel plate any
copper or brass you intend to put rubber tubing on. Rubber vulcanizes
itself to copper in short order. If you can't plate, use plenty of
silicone grease and hope for the best. (DSPs are made in vacuum
systems. I guess that's a connection!)
>
> --
> "That's not an avocado, that's a grenade!" -- The Skipper
Maybe with guacamole in the rubber-copper joint, you won't need a
grenade to get it off.
Jerry
Jerry Avins
>
> Yes, and don't forget that a firken of ale in London is smaller than a
> firken of ale in the country. While a yard of fabric in Britain is
> smaller than on the continent. Also, an English foot is smaller than a
> Cape Dutch foot and can anybody say off the top his/her head how many
> nails there are in a chain, or links in a furlong?
Are you talking surveyor's chain or engineer's chain? An engineer's
(Ramsden's) link is 1 foot, but a surveyor's (Gunter's) link is .660
foot. Lessee now; a mile is 5280 feet, a furlong is 1/8 mile ... think
think think ... 1000 Gunter's links, 660 Ramsden's links: Right?
Anyhow, 100 links to the chain, either way. Oh, yeah. Four nails make
nine inches. You know where the guy who dreamed up that unit of
measure can put them nails.
All right: how many noggins in a firkin, firkins in a hogshead,
hogsheads in a tun?
>
> More recently, Lockheed caused a multi zillion dollar satellite to crash
> since they measured thrust in foot-pound and NASA in Newtons. Maybe
> Lockheed measures speed in furlongs per fortnight... :-)
>
> It's a good thing that the French invented the metric system. Viva la
> difference! (or some such...)
>
> But let's not cast any stones here (pun intended)...
Or fire any fourteen pounders!
>
> Have fun,
I'm trying!
...
Dennis Ritchie
It is a unit of fluid flow and (at least according
to one WWW site) has differing legal definitions in various
states of the US.
Next time you're in a mine or a cave and the water starts
coming up, you can distract yourself by calculating
how many of them you are experiencing. You will need
to know which state you are in, and the volume of the mine,
in order to calibrate this against the rate of rise
of the water.
Dennis
Gregory L. Hansen
>"Gregory L. Hansen" wrote:
>>
> ...
>>
>> Actually, I use NPT as little as possible. It's just awful! Whenever I
>> tighten it up a gauge winds up facing the wrong direction or the valve
>> handles don't line up or something. To hold truly hard vacuums I need
>> goop like Torr-Seal to seal it up, and once that stuff hardens it doesn't
>> let go. I've had 1/4" brass tubing shear off on me before the Torr-Seal
>> gave way, and that's after blasting it with a propane torch and ruining a
>> gauge in the process. I wouldn't use it at all except that a lot of the
>> equipment we use comes with that kind of fitting.
>
>Torr-Seal is a high temperature epoxy; what did you expect? I've had
>good luck with Teflon tape in gauge threads, but you need to keep it
>to only a hair over one full wrap. If it's on right, you can still
The prof wanted Torr-Seal. He thought teflon tape would be too leaky in
an ultra-high vacuum system, and Loc-Tite have too high a vapor pressure.
And we did want the system to be bakeable. But I didn't expect to ever
have to take it apart. It was only after I realized I put the wrong gauge
on...
>turn the gauge a quarter turn by hand. Tightening it till it won't bo
>nay more without breaking will often expand the female thread and
>almost always guarantee a leak. All my thermocouple gauges went in
That's another reason I don't like NPT. You don't want to tighten it "too
much", but I don't have a good feel for what is "too much".
Grant Griffin
>
> ... off-topic newsgroup dropped in followups ...
>
> Jim Carr wrote:
> |
> | In article <382B3A...@iowegian.com>
> | grant....@iowegian.com writes:
> | >Sure, that whole nutty thing about powers of ten is pretty cool, but the
> | >sizes of the units themselves are so un-servicable.
> |
> | List your examples, since you had no objection to the already-adopted
> | liter and km ones. My pace is closer to a meter than a foot, so a
> | meter is hardly "un-servicable". Kilogram? Adopt that and everyone
> | will have lost weight but complain that meat costs more.
>
> In article <382C86...@iowegian.com>
> grant....@iowegian.com writes:
> >
> >Hey, waitaminute...if you measure in kilograms, how can you _ever_ lose
> >weight?! (No wonder Rotund America doesn't want to switch to the metric
> >system!)
>
> Simple. You go from weight 220 one day to only 100 the next.
>
> Same way 'Mericans think gas is cheap in Canada: overlooking that
> the price is in liters.
>
> Now, where are your examples.
>
Well, Jim, humor consists of an overlap and a contradiction:
Overlap: Since numerical values of mass and weight are proportional
(within a constant gravitational field), if people lose mass, they lose
weight.
Contradiction: Losing mass does not constitute loosing weight, because
mass and weight are two fundamentally different things.
(was that a good example?)
Grant Griffin
Dennis Ritchie wrote:
>
> The unit I like best is the miner's inch.
>
> It is a unit of fluid flow and (at least according
> to one WWW site) has differing legal definitions in various
> states of the US.
>
Do ya' think the "miner's centimeter" would be more "servicable"? (I
can just imagine somebody counting wavelengths in a cave..."342", "343",
"344" . ;-)
BTW, sorry to gush, but C and K&R are very beautiful things. (Can the
miner's inch be used to measure gushing?)
> Next time you're in a mine or a cave and the water starts
> coming up, you can distract yourself by calculating
> how many of them you are experiencing. You will need
> to know which state you are in, and the volume of the mine,
> in order to calibrate this against the rate of rise
> of the water.
which makes me wonder...what is the metric unit for measuring "deep
doo-doo"?
Grant Griffin
>
> Jim Carr wrote:
> >
> > ... note followups ...
> >
> > In article <fSYW3.7096$Ti4.7...@alfalfa.thegrid.net>
> > "Bob White" <b...@whitek.com> writes:
> > >
> > >'metric system.' Has anyone yet pointed out that the Imperial system is a
> > >binary system? 2 pints to a quart, etc.
> >
>
> i'll say.
>
> > You mean like 3 teaspoons in a tablespoon (blew out one contestant
> > on SYWTBAM)? 5280 feet in mile? 16.5 feet in a rod? 12 inches in
> > foot? 3 feet in a yard? 3 scruples in a dram (Apoth)?
> >
> > >fallen out of common usage, but I'm told that there are actually names for
> > >each time the measure is doubled.
>
> are power of 2 related but one point from Bob that is correct is the
> subdivisions of a unit in the english system are usually powers of 2
> (e.g. your socket/wrench set ... 3/8", 5/16" 11/32" ..). and he's right
> about the apparent advantages of power of 2 ratios in the denominator.
Seriously, r: If people can't work through these fractions, why not rate
them all in terms of 32'nds or something: 12/32, 10/32, 11/32 [Editorial
Aside: This exercise reveals that you got the above out of order--though
possibly you didn't intend ordering. I bring this up not to nitpick,
but as a practical demonstration of the value of the concept.] We then
see little difference in the neat integer numbering compared to
millimeters (if one is imaginative enough to disregard the "/32" part).
Jerry Avins
>
> The unit I like best is the miner's inch.
>
> It is a unit of fluid flow and (at least according
> to one WWW site) has differing legal definitions in various
> states of the US.
>
> coming up, you can distract yourself by calculating
> how many of them you are experiencing. You will need
> to know which state you are in, and the volume of the mine,
> in order to calibrate this against the rate of rise
> of the water.
>
Count on you to come up with a doozie like that!
I got to thinking after my last post in this thread that maybe a nail
isn't such a bad unit after all. It gets us back to powers of two:
four nails is a span.
Jim Carr
|
| ... off-topic newsgroup dropped in followups ...
Please note the above. My future replies will only go to sci.physics.
| | In article <382B3A...@iowegian.com>
| | grant....@iowegian.com writes:
| | >Sure, that whole nutty thing about powers of ten is pretty cool, but the
| | >sizes of the units themselves are so un-servicable.
| Jim Carr wrote:
| | List your examples, ...
| Now, where are your examples.
In article <382E73...@iowegian.com>
grant....@iowegian.com writes:
>
>Well, Jim, humor consists of an overlap and a contradiction:
The overlap between what you wrote to defend your assertion
and your assertion is the null set, equaling a contradiction
to your assertion.
Grant Griffin
>
> Jim Carr wrote:
> >
> > ... note followups ...
> >
> > In article <fSYW3.7096$Ti4.7...@alfalfa.thegrid.net>
> > "Bob White" <b...@whitek.com> writes:
> > >
> > >I just noticed this thread, and it sparks one of my biggest gripes, the
> > >'metric system.' Has anyone yet pointed out that the Imperial system is a
> > >binary system? 2 pints to a quart, etc.
> >
> > You sure stopped quickly.
>
> i'll say.
>
> > You mean like 3 teaspoons in a tablespoon (blew out one contestant
> > on SYWTBAM)? 5280 feet in mile? 16.5 feet in a rod? 12 inches in
> > foot? 3 feet in a yard? 3 scruples in a dram (Apoth)?
> >
> > >Some of the powers of 2 have
> > >fallen out of common usage, but I'm told that there are actually names for
> > >each time the measure is doubled.
>
> Jim is right that there are so few differently named english units are
> are power of 2 related but one point from Bob that is correct is the
> subdivisions of a unit in the english system are usually powers of 2
> (e.g. your socket/wrench set ... 3/8", 5/16" 11/32" ..). and he's right
> about the apparent advantages of power of 2 ratios in the denominator.
>
> numbering system (that i think is nearly universal to all human
> cultures). it kinda makes me wish we had as many fingers as the
> Simpsons, just so we sould have a base 8 (or base 16, if we count toes,
> too) numbering system. it would be a hellava lot easier to convert to
> and from binary, too.
>
> base 16, ditch english and teach esparanto and use a totally phoneticly
> sorta NExTish **NIX operating system (make sure all text uses _only_ LF
> or CR), get rid of Saddam Miloshnevich (whatever) and the U.S.
> republicans and elect me king of the world while we're at it.
>
no. you're not decisive enough.
Jerry Avins
>
> Hi Dennis,
>
> Dennis Ritchie wrote:
> >
> > The unit I like best is the miner's inch.
> >
> > It is a unit of fluid flow and (at least according
> > to one WWW site) has differing legal definitions in various
> > states of the US.
> >
>
> can just imagine somebody counting wavelengths in a cave..."342", "343",
> "344" . ;-)
>
> BTW, sorry to gush, but C and K&R are very beautiful things. (Can the
> miner's inch be used to measure gushing?)
>
> > coming up, you can distract yourself by calculating
> > how many of them you are experiencing. You will need
> > to know which state you are in, and the volume of the mine,
> > in order to calibrate this against the rate of rise
> > of the water.
>
> doo-doo"?
The stool?
Jerry Avins
>
> Dennis Ritchie wrote:
> >
> > The unit I like best is the miner's inch.
> >
> > It is a unit of fluid flow and (at least according
> > to one WWW site) has differing legal definitions in various
> > states of the US.
> >
> > coming up, you can distract yourself by calculating
> > how many of them you are experiencing. You will need
> > to know which state you are in, and the volume of the mine,
> > in order to calibrate this against the rate of rise
> > of the water.
> >
>
> Count on you to come up with a doozie like that!
>
> I got to thinking after my last post in this thread that maybe a nail
> isn't such a bad unit after all. It gets us back to powers of two:
> four nails is a span.
>
Him Again
Bob White
Yeah, specifying mechanical dimensions is another place where inches are
better. A mil is a very serviceable unit, even in the world of today's
tighter tolerances. In mm, one is always faced with fractional (decimal?)
numbers. Nobody tolerances mechanical parts in multiples of mms. When I
use tolerances greater than +- 10 mils, I usually specify dimensions and
tolerances in fractional inches. Machinists are used to it. Actually, what
(old) machinists commonly do (did) is to assume a tolerance from the
fractional denominator, like if you write a dimension like 1 27/64, they'll
assume +-1/64, unless otherwise specified. Even though everything is made
by CNC machines nowadays, I still can't help tolerancing mechanical stuff as
loosely as the requirements will allow. I'm sure the machinists convert the
dimensions to mils, though, 'cause the table dials are all marked in mils.
I too have a fractional inch vernier caliper. It's great for determining
the size of a bolt-in-hand. It's use is limited to nothing near 1/512 inch,
though. It's made from stamped metal.
There was a reference earlier about metric bolt size being good for
determining a hole size. I don't know what was being alluded to (I avoid
all things metric on an idealistic basis). I fail to understand how a bolt
size can be used to determine a hole size. As far as dimensioning drill
size for a threaded hole, the class of fit desired changes the drill size.
As far as a clearance hole, the assembly procedure as well as mechanical
things like thermal coefficient of expansion would override any clever
predestined hole size.
How about the FAA switching to Degrees Centigrade. There's another metric
boondoggle. I've noticed that a Fahrenheit degree is a good quantity, kind
of like a mil. I can reliably discern a change of 1 degree F using my
built-in senses. Now I'm seeing weather reports with fractional degrees C.
The change of one degree C is too great to be good for common usage, so it
is reported in fractions (should I be saying decimal fractions here? What I
mean is things like 24.5 Degree C). Just like the FAA. Data rate is so
valuable to them that they use meaningless abbreviations for weather
phenomena, or no abbreviation at all, just a bunch of numbers strung
together and the user is supposed to know how to decipher them. But they
can substitute 24.5 (4 characters) C for 76 (2 characters) F. The French,
again.
Bob
Jerry Avins <j...@ieee.org> wrote in message
news:382D8429...@ieee.org...
> Bob,
>
> Have you ever built anything in a machine shop? The machine dials are
> all in mils - thousandths of an inch. It's the only practical way to
> work with English units. I have seen shop micrometers 100 years old;
> they are all in mils.
>
> I have a pair of Vernier calipers with fractional inches; it's an
> abomination. Can you imagine using measurements like 179/512 inch?
>
> I prefer to work English, where a mil is a practical size. A tenth of
> a mm is too coarse, and .01 mm is too fine for most work (although I
> occasionally need fits in the order of .0002 inch.)
>
> Jerry
> --
> Engineering is the art of making what you want from things you can
> get.
> -----------------------------------------------------------------------
>
> Bob White wrote:
> >
> > I just noticed this thread, and it sparks one of my biggest gripes, the
> > 'metric system.' Has anyone yet pointed out that the Imperial system is
a
> > binary system? 2 pints to a quart, etc. Some of the powers of 2 have
> > fallen out of common usage, but I'm told that there are actually names
for
> > each time the measure is doubled. Fractional measure is also binary
(1/2
> > 1/4 1/8 1/16, etc.)
> >
> > The best argument I have yet heard for the Imperial system is this.
Take a
> > pile of sand. Divide it into two equal piles, again and again. It is
quite
> > easy to do this accurately, by inspection. Now take a pile of sand and
try
> > to divide it into ten equal parts!
> >
Ray Andraka
can't agree more though. Who's bright idea was it to abbreviate 'mist' with
'BR' ?
Bob White wrote:
> How about the FAA switching to Degrees Centigrade. There's another metric
> boondoggle. I've noticed that a Fahrenheit degree is a good quantity, kind
> of like a mil. I can reliably discern a change of 1 degree F using my
> built-in senses. Now I'm seeing weather reports with fractional degrees C.
> The change of one degree C is too great to be good for common usage, so it
> is reported in fractions (should I be saying decimal fractions here? What I
> mean is things like 24.5 Degree C). Just like the FAA. Data rate is so
> valuable to them that they use meaningless abbreviations for weather
> phenomena, or no abbreviation at all, just a bunch of numbers strung
> together and the user is supposed to know how to decipher them. But they
> can substitute 24.5 (4 characters) C for 76 (2 characters) F. The French,
> again.
--
-Ray Andraka, P.E.
President, the Andraka Consulting Group, Inc.
401/884-7930 Fax 401/884-7950
email rand...@ids.net
http://users.ids.net/~randraka
Jerry Avins
>
> Hi Jerry,
>
> Yeah, specifying mechanical dimensions is another place where inches are
> better. A mil is a very serviceable unit, even in the world of today's
> tighter tolerances. In mm, one is always faced with fractional (decimal?)
> numbers. Nobody tolerances mechanical parts in multiples of mms. When I
> use tolerances greater than +- 10 mils, I usually specify dimensions and
> tolerances in fractional inches. Machinists are used to it. Actually, what
> (old) machinists commonly do (did) is to assume a tolerance from the
> fractional denominator, like if you write a dimension like 1 27/64, they'll
> assume +-1/64, unless otherwise specified. Even though everything is made
> by CNC machines nowadays, I still can't help tolerancing mechanical stuff as
> loosely as the requirements will allow. I'm sure the machinists convert the
> dimensions to mils, though, 'cause the table dials are all marked in mils.
>
> > >
> > > just my 6.35 cents worth.
> > > Bob
It does indeed depend greatly on what one is used to. For common
mechanical parts, mils are very nice, but when dealing with really
fine stuff like optics, microns are usually better than microinches.
(My opinion!) The main trouble with microns is that now we're supposed
to call them micrometers, but those are tool as far as I'm concerned.
As for tolerances, the standard is that all dimensions given as
fractions are ą 1/64", those given to three decimal digits are ą
.001", and everything else is specified either in the dimension
itself, or in a box that specifies the default for that drawing.
I find it easier (what one is used to, I guess) to make metric parts
on an English lathe than the other way around. I even cut damn good
approximations of metric threads, but to do that, I need a 34 tooth
change gear. When I tried to buy one, the supplier told me he had
found a vendor who would make a special for around $300. (They are
standard in 20 pitch change gear sets, but I need 24.) I told him that
was no price for an amateur, and to get me a stock brass 36 from
Boston Gear; I would cut two teeth out of it. He thought I was nuts,
but it works fine. Details on request. For my purposes, 1.0039 mm is
close enough to 1 mm for threads. (I get 50.7 threads where there
should be 51 - that's exact. For 5 or 6 threads in the nut, it's not
discernible.)
By the way, do you know that standard microscope objectives throughout
the world have 32 threads per inch (0.8" dia.)? It's a Whitworth
thread form, though.
bmc...@ti.com
remember they quoted the size of the bolt shaft, not the head size. As to
measures: Which weighs more- a pound of gold or a pound of feathers?
Bill
Jerry Avins <j...@ieee.org> wrote in message
news:382BB380...@ieee.org...
> Mike Percy wrote:
> >
> > Phil Martel wrote:
> > >
> > > Jerry Avins <j...@ieee.org> wrote in message
> > > news:3829002F...@ieee.org...
> > > > Grant Griffin wrote:
> > > > >
> >
> > [metric system joke?]
> >
> > Long distances and speeds I still have to convert mentally to miles and
mph, and
> > knowing some key numbers, like 10k == 6.2 miles and 55mph == 88kph
helps. But
> > thanks to 2 liter bottles of Coke, .5 liter bottles of water, 750ml wine
> > bottles, metric socket wrenches, etc. I (and I hope America in general)
are
> > getting used to metric measurements. Those metric soket wrenches make
me think
> > everytime how stupid English system is: all the English sockets are in
> > fractions, and of course are simplified 1/16, 3/32, 1/8, ... Finding
the next
> > size larger or smaller requires doing fractions in my head (ouch)
because I
> > can't keep my sockets in ascending order all the time. If I've got a
6mm socket
> > and it's a smidge too big, I know the next size up is 7mm.
> >
> > BTW, I read that the Space Station has a mix of metric and english
parts -- hate
> > to be the astronaut who goes EVA with the 9/16ths wrench when he needed
the
> > 14mm.
> >
> > --
> > "I don't know about your brain, but mine is really...bossy."
> > Mike Percy, Senior Computer Scientist, Scientific Research Corp.
>
> I keep a full set of sockets and other wrenches in my car. Now, I need
> both American* and metric, and I worry about a hernia every time I
> lift my tool box.
>
> *English wrenches are different. Back before they went metric, their
> wrenches had the same markings as ours, but they didn't fit our nuts.
> An American wrench is enough oversize to fit on a standard tolerance
> nominal nut. An English spanner is nominal, and the nut is enough
> undersize to allow for both tolerances. Something like that, anyhow.
>
> There were other idiocies in those days. French metric nuts wouldn't
> fit German metric bolts if the same nominal size; the thread forms
> were different. German, French, and British thread forms were
> different - the British had several different ones - and some Swiss
> sizes used the French form, some the German. Many of these thread
> forms needed a different lathe tool to cut each pitch because they had
> pitch-dependent radii. (The French form came to a point.) Finally,
> when the Common Market forced standardization, they all adopted the
> American form. It has an easily measured angle - 60° - and flats,
> making a single tool suitable for a large range of sizes.
>
> Most "metric" sockets used throughout the world fit American (1/2,
> 3/8. and 1/4 inch) drivers. American Spark plugs have always been
> metric. The sizes are such that there is both an American and a metric
> wrench to fit each. Before they went metric, the British needed
> special spark plug wrenches. And on, and on!
Bob White
Pythagorean Theorem on the refrigerator door (local bulletin board) where I
found this. It seemed only fair. I only hope that squaws aren't sexist or
otherwise politically incorrect. I think that hippopotomi are still safe.
USEFUL METRIC CONVERSIONS
1 triillion microphones = 1 megaphone
1 million bicycles = 2 megacycles
2000 mockingbirds = two kilomockingbirds
10 cards = 1 decacards
1/2 lavatory = 1 demijohn
1 millionth of a fish = 1 microfiche
453.6 graham crackers = 1 pound cake
10 rations = 1 decoration
10 millipedes = 1 centipede
3 1/3 tridents = 1 decadent
10 monologs = 5 dialogues
2 monograms = 1 diagram
8 nickles = 2 paradigms
2 baby sitters = 1 gramma grampa
Bob
Clay S. Turner
Clay
Richard Herring
> If you had a Triumph Motorcycle, you needed Wentworth wrenchs.
Whitworth.
> As I
> remember they quoted the size of the bolt shaft, not the head size.
Something like that. And they changed by one notch when wartime
economy measures reduced the size of the head.
--
Richard Herring | <richard...@gecm.com>
Jim Thomas
And don't forget, a nanocentury equals pi seconds.
"Clay S. Turner" wrote:
>
> And micronesia is where you forget a million things.
>
--
Jim Thomas E-mail: jth...@bittware.com
Senior Applications Engineer Web: http://www.bittware.com
Bittware, Inc Tel: (703) 779-7770
The sooner you get behind, the more time you'll have to catch up.
Grant Griffin
>
> And don't forget, a nanocentury equals pi seconds.
>
Now don't get me started on the unservicability of the metric system's
version of pi...