Reply #16: Probably significant

[slackmaster]

I do machine work as a hobby. The moving parts on most lathes, milling machines, etc. and English System measuring tools are graduated in thousandths of an inch (.001").

Most metric machine tools and instruments are graduated in hundredths of a millimeter. .01 mm = .00003937", a much finer degree of precision. And the ease of determining tap drill sizes and so on totally blows away the English measurements. The formulas are the same but because Metric drills are mostly in whole numbers of mm the calculations are much simpler.

The only non-Metric measure I would keep is the Farenheit temperature scale. It's in finer gradations than the Centigrade system, and well suited for measurements that predict human comfort.