On this day in 1866, an act of Congress, signed into law by President Andrew Johnson, made it “lawful throughout the United States of America to employ the weights and measures of the metric system in all contracts, dealings or court proceedings.”
Andrew Johnson was President when this was passed.
Our best shops are operating in metric and measure in Microns- millionths of a meter.
How large is a micron?
Happy Metric Day. And a hat tip to David Parker of Metric Machining and Mike Preston of Micron Manufacturing.
And to all of the engineers, machinists and technicians who call the metric system “theirs.”
Speaking of Precision Blog 
