The cost of maintaining dual standards is enormous:
When the Confederation of British Industry (CBI) surveyed its members about metrication in 1980 — after 15 years of British metrication — they found that
"... the extra cost of continuing to work in dual systems of measuring was around £5 000 million every year."
This cost must be a huge drag on competitiveness. Even if the USA does not like metrication internally, many foreign markets will demand metric products, and manufacturers have a choice of dual standards of losing buiness.
To an individual, an additional or new machine is an unwelcome cost, but if everyone is replacing old machines over a period, the simplification of uniform standards must be a big benefit. There is nothing to stop a lathe from being set to 25.4mm to cut 1" for old legacy compatibility.
Contrary to popular belief Canada is not realy metric, it is only officially metric. I have lived here all of my 53 years and it is metric for visitors as the speed limit and gas and milk(not butter 454grams =1 lb) are all metric but materials to construct any thing are all in inch sizes, so when you design something if you want to not wait months for the material to arrive, you must use inch sizes. Going all metric would help as all of our new engineers have to learn ft/lb, psi....
The idea of metric conversion is much easier than the application. Try and purchase Metric paper for your printer, then try and re-adjust your printer to use it. Architectural building drawings are still mostly in Feet and Inches. When was the last time you found a metric drill index? They are all SAE with the metric value in parenthesis. All this is after almost 50 years of trying to change. There are not enough market forces to demand a change to metric and depending on the government to oversee this dooms it to failure before it even starts. Saying the US and Britain are the only 2 countries using this backward system is perhaps a bit elitist. I have no hard data, but I think these 2 backward countries do contribute a significant percentage of the worlds industrial output. Change is happening slowly. Maybe in another hundred years we'll all be metric but I wouldn't count on it.
I have been a machinist and have a few machinr tolls at home. I participate in several machinist forums and have seen this discussion come and go over several years. As long as one understands the system one is working ai and how it relates to the other system there is little, if any, problem. Sure, The Brits and the Americans still work with inches and the rest of the world works with meters. We can both make parts that are completely interchangeable with no extra effort. The arguments generally come down to - your system is wrong because it isn't my system.
Consuder the cost of retooling. If I was active in a machine shop my measuring tools alone would come to approximately $3000.00 to replace. Quite a hit to the individual craftsmans wallet and they aren't paid all that great anymore.... And then the companies that have thousands of dollars worth of tooling that would have to be replaced. And for what? so we could say we made it to 25.40MM instead of 1.000"?
The anecdotes that are used to justify metricization are more examples of poor communication and poor practice. The satelite and mars probe problems were more likely caused by a rushed production and testing program and revealled a need for better quality control. Rushed work in metric can still come out as crap. and chromed crap in metric or english is still crap.
As far as I know, the UK and the USA are the only two backward countries to remain non-metric in everyday life. All science and most engineering is metric already. The funny thing is, the UK and USA cannot even agree on units - US gallon is 3.8 litres and the UK gallon is 4.55!
The US claims "a pint's a pound the world around" but that is only true in the USA, in the UK a pint is 20 ounces. Talk about parochial!
TJ, the units are not the only potential pitfall. When I first started programming satellites, we were given the lecture about telemetry. Specifically, we were told to pay attention to the sign of the numbers and the endian-ness of the numbers. Evidentially there was a satellite where the mistake was made and the programmer shot the craft into deep space instead of putting it into a stable orbit.
Jon, it's very important to use international metrics/standards in business, especially with other countries, otherwise conversion from one unit to other is a problem. For domestic purposes, if we are using our own metrics and standards, nothing going to be happen because both the seller and buyer are following the same metrics.
The only way is to do it by government edict, in the way South Africa and Rhodesia did in the 70's. After such-and-such a date everything will be made in metric. Imperial measurements will no longer be taught in school. Old equipment can be maintained but all new equipment will be metric. S.Africa went further and banned the importation of imperial measuring equipment.
I have done a couple of science classes here in the US and it always amazes me how 'conversions' are taught and seen as a very abstract concept. One prof got all annoyed when I pointed out that mixing units(sq metres/acre) was not standard.
However, it takes years to clean out 'imperial'. In the 80's a fellow apprentice fitter- and-turner was happy because he had been given a set of imperial micrometers. If you make imperial size parts make them in imperial - conversions(either way) are never the same.
Here in the US we brought in some European equipment. We had to fabricate mold plates locally. Our machinists insisted on converting to inches(on CNC machines). 80 plates later, and all 1/16" too short I was free to say 'I told you so'.
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