Didier Juges wrote: > In France, and I suspect in the rest of the world, machinists talk in > 1/100th of a mm (centieme in French). The 'centieme' is a very good > fractional unit when dealing with hardware. It is not harder to talk in > 1/100th of a mm than in 1/1000th of an inch.
Talking isn't the problem, actually machining to 1/100th of a mm is the problem. Machinists, and the machines they use, run out of steam around a thousandth of an inch. 1/100th of a mm is a practical impossibility for a lathe, or milling machine to achieve. But 1/10th of a mm is too course for operations involving fit (bearings, press fits, ...). So you end up counting in 4/100ths of a mm, rather than 1/1000ths of an inch. Cutting threads is a real nightmare with non CNC metric lathes, but super easy with non CNC English lathes. > > After 33 years in France, and 22 here in the US, I must say I have not > completely converted, by a long shot. The Imperial system is just too > ridiculous. It is an offense to common sense. BTU/hr? please spare me :-) I'm puzzled about why that particular arbitrary constant bothers you. A BTU is the amount of energy necessary to raise 1 cubic foot of water 1F in temperature. A BTU/hour takes one hour to raise the temperature of the water. It is no more, or less, arbitrary than the calorie, but it is a whole lot less wierd than a calorie/hour, or a kilometer/hour for that matter. Life will always be a blended system, unless you decide you want a metric day, metric week, metric year... I don't think that nature will accommodate you very well. -Chuck Harris _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
