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ENGINEERS FORUM
US Metric System Debated (Engineers
Exchange Blows)
Here is a collection of comments in response to a previous story on SI standards.
GO METRICS - US Should Standardize
from James R. Meyette, CNC Programmer
The metric standard is a standard which should be adopted in the US. I
worked for a Japanese Machine Tool builder a few years back and we had a
customer that had a certain performance issue (he was programming metric
parts in inch mode). We told him to run the machine in metric and it would
solve his issue. He balked and asked "What's the difference?",
measurement is measurement. Not true we said. "Everything about the
machine is Metric" we said. The ball screws are metric pitch, the
control takes inch measurements and converts them internally to metric,
makes the move, then converts it back to inch for display purposes. Just
another glaring reason the US
needs to get on board at full speed ahead with SI units. Besides, it's so
much easier to use.
NO METRICS - Conversion to Metric Will
Hurt Small Businesses
from Dean Herbst, Agricultural Equipment Repairs
I would like for us to stay with the US standards and not go to the
metric system because it would cost me thousands of dollars. The big thing
is in nuts and bolts. Where I have a bolt size 7/16", I do not know
for sure how many different nuts and bolts I would have to stock. A #12 is
very close to a 7/16". There is a #12 with a 1.00 pitch, 1.25 pitch,
1.50 pitch and 1.75 pitch, and that's just the US standard. In metric sizes, a
#12 from Japan will not
work with the US
standards and a #12 from Italy
will not work in place of a Japanese made part, and none of the #12 US parts will
work for those ether. I think that any equipment that is imported to the US should be required to be in all US
standards.
GO METRICS - Avoiding Metrics is
Economically Irrational
from Tim Stephens
I read your Standardization Hindered By Multiple Measurement Systems with
great interest. I firmly believe that industry, especially the die and
stamping field, must engineer and manufacture in SI units to compete on a
global scale. Ten years ago, I was a member of a task force at General
Motors to benchmark and publish die engineering standards. It literally
took me everyday for six months to convince the team we should be using
hard metric. Once convinced, we saved 30% in costs due to global
availability of commercial components. Since then, I have consulted several
companies on metrication, and have published articles on the topic in my
column that appears in a well-read trade magazine. In the global markets
today, using any measurement system other than SI is an economically
irrational practice governed by emotion.
GO METRICS - European Manufacturers
Frustrated With US Resistance
from Bonne A. Rook, The Netherlands
The US
are refusing the metric system as "it has not been invented here"
(NIH as we call it). They prefer to use imperial standards, as their whole
thinking is imperialistic. I am refusing any quotation or supply from US
that is not metric. Tell them that they have else to shut up. Europe has
already been spoiled with MacDonalds, Coca Cola and Marlborough. Even the good old England is
metric now. On the road the signs are still in miles, but the miles are
metric. Exactly 1600 meters. As long as the US is not going to be metric,
it is for me "Yankee go home."
NO METRICS - And Speak Chinese Too?
from Steve Woolley, Formulation Chemist
While it may be easier to adopt only one system, in the era of inclusion
and acceptance, why can we not be bi-lingual engineers? Does Mr Schweisthal
also suggest that we all learn to speak and write Chinese sinces there are
more Chinese people in the world than any other nationality?
NEUTRAL - Metric Values Vary
from Fred Saalbach
The metric system as practiced is really not any better then the US system
in terms of consistency. Many nations put their own flavour on things. We
could actually argue that the US
is already on the metric system as in the late 1950's the US units
were redefined in terms of the metric units.
Your issue is really having parts that are interchangeable with metric
parts. But which metric parts JIS, ISO, EN, GOST or whatever? In many
product classes there is a mixture of hard conversion and soft conversion
parts. Hard conversion is a part that was redesigned so that the physical
dimensions of the part conform with the ISO guidelines on selecting
dimensions. Soft conversion might only indicate that the English dimensions
are expressed in their metric equivalent. This is often an installed base
issue. Do you really want the hardware store to stock 70mm pipe and then
find you need to connect it to the 3 in sanitary drain in your house.
GO METRICS - Do The Math
from Dr. Michael Graefe, Germany
I am happy to read your opinion about the metric system. I find it so much
easier to use. I always amuse American engineers by
1 N*m = 1 J = 1 W*s
NEUTRAL - Metric Values Vary (What is the
standard?)
from John T. Albers, Senior Project Engineer
To say every other nation is playing by the same rules as long as they have
adopted the "metric system" is very misleading. There might be
considerable conformity between nations on the subject of electrical
engineering. However there are no less than 5 standards for hose and tube
fittings (SAE, JIS, DIN, British, NPT, ISO, etc.). Have you ever looked up the
section modulus of a typical wide flange shape in metric units? Inches to
the third power convert to some exponential number in millimetres. And how
about pressure? The US
standard is pounds force per square inch, whereas some nations use newtons
(force) per meter squared, others kilograms (mass) per millimetres squared.
Which units should we adopt?
While I was in college my text books typically would have problems that
involved both SI units and "Imperial" units. The thing that
struck me was that it was much easier to comprehend the magnitude of the
"imperial" units than SI. Perhaps it was from my upbringing in
the U.S.
By the way, the "metric system" originated during the French
Revolution as a reaction to "imperial" units. A ten day week was
also proposed since the notion of a seven day week is based on the Bible.
GO METRICS: Blam! Crack! Pow!
from Ian Hook
Bloody Americans, give them an inch and they standardise on a mile!
NEUTRAL - US Engineers Already Use
Metrics
from Jim Brown, Design Engineer
I think Mr. Schweisthal has misrepresented a great number of young
engineers coming up today. During my college years English units were
typically an afterthought. Most exams and homework featured problems solved
in metric units. The fact is many younger engineers work almost exclusively
in the metric system because we've grown up (academically) with it.
In my brief career (I have been out of college only 3 1/2 years) I have
worked with or for Cummins, Case (prior to the New Holland merger), John
Deere and Hitachi
and can count on one hand the number of English unit prints I've used or
drawn.... Working in the manufacturing of diesel engines and the design of
hydraulic excavators, I can say that my brain thinks metric first. I'd much
rather deal with decimal millimetres than fractional inches. I use English
units only in terms of putting gas in my car, driving to work, lifting
weights at the gym and woodworking hobbies. Even working on my car requires
metric tools and measuring devices lest I would spend my Saturdays trying
to figure out why my 89mm cylinder bores aren't exactly 3.5 inches in
diameter...and what fun would that be.
GO METRICS - Not Adopting is Lliving in
the Past
from Niel J.P.Fagan, Lab. and Process Superintendent,
England
John P. Schweisthal hit that nail squarely on the head, but in England we
have it even worse with Metric, English Imperial and American English to
contend with.
We buy units from Asia and its metric, from Europe metric again, from USA a horrible
mixture some (few) metric but mainly weird sizes that make little sense
like #8/32 threads. Yes we still have some older kit with BSF/BSW, but at
least they make some sense and you can still get most sizes of nuts and
bolts off the shelf, unlike most US threads.
Yes we English have gone metric, for MOST things, and its much easier to
build systems as a result, we still retain BSP (our imperial pipe thread
standard) which has been adopted by most of the rest of the world and it
now has an ISO designation too.
We understand that the USA likes to do things differently, BUT using
non-standard thread systems and the measurement systems that go with them
(or is that the other way round) is just living in the past, as with most
industries here its modernize or die, or at least get stuck in an
unfavourable trading position time-warp.
I was trained when inches were king, moved through the transition, and
apart from historic equipment (and vehicles, a 1950's Land- Rover being my
preferred mode of transport, for ecological reasons as much as anything
else) most everything is now metric, and fits first time without wasteful
and sometime dangerous adaptors made by unskilled workers "just to
make it fit", re-building is an off the shelf prospect with standard
parts and no problems with odd threads etc.
Move on, don't live in the past, the future is out there, grasp it with
both hands, sure it'll hurt for a while, but change always does, and go for
it, the old'uns will complain, but working in metric is easier, base 10
calc is quicker, and in 15-20 years you may have even have caught-up with
the rest of the world!
Go to More Comments on SI Standards.
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