Here in the UK the engineering industry has been using the metric SI
system for over 30 years. Although most of the structural sections
manufactured by Corus (the new name for British Steel) continue to be
soft metric conversions of sizes from yesteryear!
As previous correspondents have mentioned it certainly takes time to get
used to the 'other' system. However the metric system using base 10 does
seem to be the easiest and most logical. I have recently been working on
the technical parts of a new US catalogue for the company I work for.
Being limited to converting metric dimensions to inch sizes with a
maximum fraction of 1/16" isn't easy. However, I did notice fractions in
the LRFD (volume 1 section 1 page 141) that I personally think are
ridiculous ie.2 65/128". Does anyone actually work to these kind of
figures? Obviously the use of the metric system, in this instance
63.7mm, would be a little easier for me to understand.