Dear Bill,
You're right about the old monitors. It was absolutely shameless that
the television industry and then the computer screen industry did not
use the visible part of the screen to sell their products and then to
do so in old archaic pre-metric measures that they would not and do
not use for their own manufacturing as they are all metric companies
(internally for efficiency and dumbed down for marketing). One of
their rationalisations for their dishonesty was that they were
measuring the extent of the phosphor coating inside the cathode ray
tube. This policy of obfuscation is still with us in Australia today
to the detriment of the education of every child in Australia and at
great additional cost to our industries.
It has been interesting for me, as a student of measurement, to see
the development of what I now think of as 'dishonesty cultures' in
particular industries. Once the television industry realised that it
could confuse customers by using nominal inches rather than visible
inches, they got stuck. No-one now in that industry has the courage to
go outside the square and use honest units and honest measurements.
It's almost as if the screen making executives prefer the approval of
the competitive peers rather than dealing with their customers honestly.
This is an interesting phenomena that has also occurred in other
industries, sometimes going way back in history. Let me give you
another couple of examples.
Pipe and tube are two different things that look similar to anyone who
has no need to design with them. Tube is used for construction where
the outside diameter and the thickness of the walls is important for
its structural strength. Pipe is used for carrying gases or liquids
where the most important feature is the size of the hole in the middle
so internal diameter is important. Suppose that you have a tube and a
pipe that both have an internal diameter of 10 millimetres and an
external diameter of 12 millimetres with a wall thickness of 1
millimetre. This could be called a 12 mm tube or a 10 mm pipe. Given
this option it has been the habit of generations of tube and pipe
manufacturers to make it appear to supply 'more' by giving both of
these the larger size of 12 mm and then calling it a 'nominal size'.
Most companies would then dumb down the real size for their
advertising and catalogs by noting that this is close to half and inch
and then calling this a 'nominal half-inch' pipe or tube. As there is
no standard control over this practice the appearance is that
companies do this on a more or less random basis and those of us who
need hard data for designing have to spent countless hours finding the
true and real specifications for our design work. Most designers learn
about a few sizes, get to know their reality by research, and then
stick with them ignoring all other possible solutions to design
problems. It is a great shame with enormous costs.
Beer makers have a long tradition of profound dishonesty. Brewers in
ancient Rome discovered that if you chose your ingredients carefully
you could make a beer that produced so much froth that beer sellers
could fill your non-see-though drinking container with a short measure
of beer. However, Roman beer drinkers (often belligerent legionnaires)
demanded a full serve. A compromise was reached in which a mark was
made on the outside of the drinking cup with a line of paint; the
drinker could then check with his finger whether the beer level was
'up to the mark'. Gradually the practice and the Latin word for paint
moved with the Roman soldiers to England where the word changed to
pint where it continued to have the same use until see through glasses
became available so that drinkers could see the proportion of beer to
froth. The on-line etymological dictionary gives this definition of
the word, pint:
1384, from O.Fr. pinte (13c.), from V.L. *pincta (cf. O.Prov., Sp.,
It. pinta), perhaps ult. from L. picta "painted," fem. pp. of pingere
(see paint), on notion of a painted mark on a vessel indicating this
measure. Used elliptically for "pint of ale" (or beer) from 1742. Pint-
sized "small" (esp. in ref. to children) is recorded from 1938.
The beer makers tradition for dishonesty continues with the British
'pint' that is served in a container that will only hold a legal pint
of beer if it is served filled absolutely right to the brim of the
container. But beer drinkers like to have some froth with their beer,
so they have to accept a smaller 'nominal pint' (of about 500
millilitres instead of the 568 millilitres, which is the legal
definition of a UK pint.)
Cheers,
Pat Naughtin
Geelong, Australia
On 2009/01/25, at 1:58 AM, Bill Potts wrote:
To answer your question about monitors, the problem was only with
CRTs, for which the measurement was the whole diagonal, rather than
the visible diagonal. For LCD monitors, the two values are the same,
because the entire area is visible.
Why they're stated in inches, sometimes even in metric countries, is
another matter.
Bill
Bill Potts
WFP Consulting
Roseville, CA
http://metric1.org [SI Navigator]
From: [email protected] [mailto:[email protected]] On
Behalf Of Jeremiah MacGregor
Sent: Saturday, January 24, 2009 06:43
To: U.S. Metric Association
Subject: [USMA:42427] Re: Pipe fittings in the USA
Michael,
That is strange. Why isn't a half inch pipe really a half inch? If
it is really 15 mm, then why not call it a 19/32 inch, which is
close enough?
There is also a big difference between 3/4 inch (19 mm) and 23 mm.
One would think the naming would be closer to actual.
I had a similar experience with buying a computer monitor some years
ago. I was looking at 17 inches and could not understand why
different brands had different diagonals and all were less then 17
inches. Why don't they call them by their exact size?
Jerry
From: Michael Payne <[email protected]>
To: U.S. Metric Association <[email protected]>
Sent: Sunday, January 18, 2009 8:53:52 PM
Subject: [USMA:42360] Re: Pipe fittings in the USA
I'm not somewhere to measure this right now, but it's been my
experience that US copper pipes are actually hard metric but named
to a nominal inch size which is some instances can be way off the
actual size. I can measure this stuff when I get home, I seem to
recall the 1/2 inch is actually 15 mm OD on the pipe ID on the
fitting that connect the pipes. I think the 3/4 inch is 23 mm but
I'd have to check.
Mike Payne
----- Original Message -----
From: Pat Naughtin
To: U.S. Metric Association
Sent: Wednesday, 14 January 2009 03:12
Subject: [USMA:42337] Pipe fittings in the USA
Dear All,
I found this Q and A at http://en.allexperts.com/q/Plumbing-Home-1735/2008/3/Copper-pipe-sizes-1.htm
where an Australian asked for information about copper pipe sizes
in the USA. The answer included this line:
But to answer your question, copper pipe and fitting for plumbing
are called out by their nominal size. 1/2" copper pipe is actually
5/8". 3/4 is 7/8, etc. However, refrigeration tubing and ACR pipe
(cleaned and capped for med gas) is called out by it's OD. 1/2" ACR
is the same size as 3/8 type L, M or K. 5/8" ACR is the same as 1/2"
L, M or K.
I was amused to find that 1/2 is actually 5/8 etc. and I have no
idea what l, M, or K might mean.
By the way, the Australian referred to a 'nominal' 1/2 in. pipe that
has really measured 10 millimetres (inside diameter) and 12
millimetres (outside diameter), giving it a wall thickness of 1
millimetre, for many years.
Cheers,
Pat Naughtin
PO Box 305 Belmont 3216,
Geelong, Australia
Phone: 61 3 5241 2008
Metric system consultant, writer, and speaker, Pat Naughtin, has
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modern metric system smoothly, quickly, and so economically that
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