Metric system problems

[FrankJ]

Most modern analytical scale use some kind of force balance. Such as a strain gauge which is really just a fancy spring. They actually have to be calibrated in place to account for variations in gravity among other things. I remember the old analytical beam balances: little knob light & mirrors. Temperamental things.

I typically convert to SI units for calculations involving mass. It is just easier. As long as you don't confuse Newton Meters with Joules.