Different Units - Different Accuracy |
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| It should be
observed that inch units are inherently more "inaccurate" than millimeters. Not
because there is a problem with the units themselves (they are both adequately defined
using light waves and atomic clocks etc.) - but because the inch is 25.4 times longer than
the millimeter. If a length is described using inches and 2 decimals e.g. 1.25" the
rounding-error in the CAD system can be +/-0,005 inches. On the otherhand, the same
length, 31,74mm can, at worst, be in error by +/-0,005mm. Hence it is clear that the millimeter is more accurate. At least for the purposes of CAD drawings. In the case given above, the inch value could have an error of +/-0,127mm whereas the millimeter could only have +/-0,005mm. The same can, of course, be said of the meter in relation to the yard (or the foot). The yard (or the foot), being shorter than the meter, will always be "more accurate" than the meter! Some people will say that fractional inches are better than decimal (metrics) because you can desrcibe 1/3" exactly! That is true. But if you were to describe the same length in millimeters you would say 8,467mm which is only 1/3000" too big. Give me feet any day - but keep your inches! One easy way of reducing the possibility of introducing errors into your drawings is to convert to metrics. Accuracy Advisor can help you do that. MEtricator will do it for you! |
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| "Which mode is better, inch or metric?" (From a "CNC" perspective) | ||
| CAD/IQ (Accuracy Advisor's 3D cousin) - many interesting articles | ||
| US Metric Association (USMA) (Millimeters are, after all more accurate!) Check out "Did you know that..." | ||
| The lighter side of metrication! | ||