http://www.csemag.com/single-article/soft-and-hard-metric-conversions/8203d3c07c36773c13673e99ca608165.html
Quote:"Soft metric" is not a mix of imperial and metric measurements, and the Dept. of Defense does not recommend it for engineering drawings. They would be better off forbidding it than not recommending it. Our CAD system would not allow inch entry or dual dimensioning. There were a few cases of unusual multiples and submultiples of 25.4 mm, but the engineer had to convert by hand (to increase the pain) and enter in metric. Most learned.
