Dear All,
Yesterday, I received an email that contained this observation:
The only thing I have to think twice about seems the
Aussie practice of using mm for large measurements. I would personally
never think "650 mm" when I am cutting a piece of wood for something
that is
65 cm long. But I have a tape measure that is written that way and I
find
it very annoying to use. And when they say in car manuals that the
wheelbase is umpteen zillion mm, I mentally have to adjust it to meters
or
cm.
Here is my response:
I have made an analysis of the various occupations in Australia and the
length units they prefer to use. From the 113 occupations listed by the
Australian Bureau of Statistics, the results are as follows:
90 occupations � millimetre users
Aircraft Maintenance Engineer (Avionics), Aircraft Maintenance Engineer
(Mechanical), Aircraft Maintenance Engineer (Structures), Automotive
Electrician, Binder and Finisher, Blacksmith, Boat Builder and Repairer,
Bricklayer, Broadcast Transmitter Operator, Business Machine Mechanic,
Cabinetmaker, Cable Jointer, Carpenter, Carpenter and Joiner,
Communications
Linesperson, Computing Support Technician, Dental Technician, Drainer,
Electrical Engineering Technician, Electrical Powerline Tradesperson,
Electrician (Special Class), Electronic Engineering Technician,
Electronic
Equipment Tradesperson, Electronic Instrument Tradesperson (Special
Class),
Electroplater, Engraver, Farrier, Fibrous Plasterer, Fitter, Flat Glass
Tradesperson, Floor Finisher, Furniture Finisher, Furniture Upholsterer,
Gasfitter, Gem Cuter and Polisher, General Communications Tradesperson,
General Electrician, General Electronic Instrument Tradesperson, General
Fabrication Engineering Tradesperson, General Mechanical Engineering
Tradesperson, General Plumber, Glass Blower, Graphic Pre-Press
Tradesperson,
Greenkeeper, Gunsmith, Jeweller, Joiner, Leather Goods Maker, Lift
Mechanic,
Locksmith, Mechanical Engineering Technician, Mechanical Services and
Airconditioning Plumber, Medical Grade Shoemaker, Metal Casting
Tradesperson, Metal Fabricator (Boilermaker), Metal Machinist (First
Class),
Metal Polisher, Motor Mechanic, Optical Mechanic, Painter and Decorator,
Panel Beater, Patternmaker-Grader (Clothing), Piano maker, Piano Tune,
Precision Instrument Maker and Repairer, Pressure Welder, Printing
Machinist, Refrigeration and Airconditioning Mechanic, Roof Plumber, Roof
Slater and Tiler, Saw Maker and Repairer, Screen Printer, Sheetmetal
Worker
(First Class), Shipwright, Shoemaker, Signwriter, Small Offset Printer,
Solid Plasterer, Stonemason, Textile, Clothing or Footwear Mechanic,
Toolmaker, Upholsterers and Bedding Tradespersons (nec), Vehicle Body
Maker,
Vehicle Painter, Vehicle Trimmer, Wall and Floor Tiler, Watch and Clock
Maker and Repairer, Welder (First Class), Wood Tradesperson (nec), and
Wood
Turner.
10 occupations � cm and inches users
Apparel Cutter, Baker, Chef, Chef � Head Chef, Cook, Dressmaker, General
Clothing Tradesperson, Pastry Cook, Picture Framer, Sail Maker, Screen
Printer, and Tailor.
6 occupations � cm, feet and inches users
Canvas Goods Maker, General Gardener, Head Gardener, Landscape Gardener,
Nurseryperson, Tree Surgeon
7 occupations where length measures are less important
Butcher, Buttermaker or Cheesemaker, Confectioner, Hairdresser,
Smallgoods
Maker, Supervisor, Hairdressers, Supervisor, and Meat Tradespersons.
90 occupations = 80 %
10 occupations = 9 %
6 occupations = 5 %
7 occupations = 6 %
113 occupations = 100 %
The reason I carried out this survey was because I had had the
opportunity
to work on the metrication programs of several building trades where the
metrication program was quick, smooth, and relatively cheap (typically
completed in less than a year). This was before I moved to the textile
and
clothing industries where the metric transition is still muddled, bitter,
and enormously expensive (nowhere near completion after 35 years and
counting).
In comparing these metric transitions, I was immediately struck by one
significant difference: the building industries had all chosen the
millimetre as their small length unit and the textile industries had all
chosen the centimetre as their small length unit.
Despite this clear observation it took me years (I must be a slow
learner)
before I realised the reason for this profound difference.
If you choose millimetres as your small length unit you immediately
achieve
two other effects: you remove all references to vulgar fractions (such as
halves, 1/16ths, and mixed numbers such as 3 7/8) and you also remove all
references to decimal numbers (such as 1.2, 2.34, or 3.456).
For many folk in the building industry (many of whom have limited
numeracy)
this was a considerable advantage in adopting the metric system for all
their length measurements � the issue of larger numbers proved, in
practice,
to be quite insignificant. And this benefit then carried over to their
other
measurements such as grams, kilograms, millilitres, litres, watts, and
kilowatts. Without the prefix centi none of these quantities necessarily
involve fractions on a building site.
On the other hand, the choice of centimetres in the textile industry gave
no
such clear advantage to textile and clothing workers. The halves and
quarters formerly applied to inches were simply transferred to half
centimetres and quarter centimetres. In addition, as a further
impediment,
textile and clothing workers had the added disadvantages of decimal
fractions of centimetres (which they had never used before) and, even
worse,
all the problems of converting between decimal centimetres and fractions
of
inches to suit their large stock of old patterns. It's no wonder that
they
have almost universally chosen to revert to inches and fractions of
inches
because they believe that they understand them better than this (to quote
a
shirt maker) 'new metric muck'.
I suppose that I have only made these observations because I have had the
opportunity of working with many companies as they made (or tried to
make)
their metric transitions, firstly in the building trades and then later
in
the textile and clothing trades.
I would take great care with your choice of small units if you are
helping
with metric transitions as centimetres can seem initially an obvious
choice
but their long term effects can prove to make a metric transition
remarkably
difficult.
Cheers,
Pat Naughtin ASM (NSAA), LCAMS (USMA)*
PO Box 305, Belmont, Geelong, Australia
Phone 61 3 5241 2008
Pat Naughtin is the editor of the free online monthly newsletter,
'Metrication matters'. You can subscribe by going to
http://www.metricationmatters.com and clicking on 'Newsletter'.
* Pat is the editor of the 'Numbers and measurement' chapter of the
Australian Government Publishing Service 'Style manual � for writers,
editors and printers', he is an Accredited Speaking Member (ASM) with the
National Speakers Association of Australia, and a Lifetime Certified
Advanced Metrication Specialist (LCAMS) with the United States Metric
Association.
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