Absolutely. But ohhhh... those instruments. I saw a friend with an electronic gauge put it on one end of a 1' bar of steel. He put the gauge on one end and zeroed it. Then he breathed on the other end. We watched the needle cliiiiiiiimmmmbbb.... then fall back to zero over 3 minutes or so.
Yes exactly. I was blown away (ahem) and instantly regretted my life choices, which until that point had not involved microns in any way shape or form.
The instrument readout looks like this: https://www.perfectionmachinery.com/assets/item/hires/40961_... except his had adjustable ranges. Every tick on that needle is one millionth of an inch - by comparison a red blood cell is about 40 millionths and the smallest bacteria is about 5 millionths long. This instrument has a read head connected with a cable, that has a finger on it that rests on the part under test. Under normal use you'd slide the part around under the finger to look for variations in thickness - obviously that requires and extremely flat surface to slide around on.
Yes. There's a joke in machine shops working to insane tolerances.
"just breathe on it till it measures in spec"
There's a great video by oxtoolco on youtube where he's seeing which is "thicker". A sharpie mark or some machinists blue. Measuring in the millionths of an inch.
Spoiler: a sharpie mark is about one ten-thousandth of an inch thick (depending on color, because size of the pigments!)
An interesting use of this bit of trivia: when machinists are trying to grind a block square, they may measure a slight deviation from 90 degrees - i.e. they see that each of the two opposite faces are parallel, but the angle they make is out of square. They have a parallelogram.
If you draw it, you can see that if they put it back on the grinder, and shim one edge of the face contacting the table, when they grind the opposite-to-the-table face they can bring it closer to square because they'll be grinding a wedge off the top face.
They use a quick swipe of a sharpie marker as a shim.
Absolutely. But ohhhh... those instruments. I saw a friend with an electronic gauge put it on one end of a 1' bar of steel. He put the gauge on one end and zeroed it. Then he breathed on the other end. We watched the needle cliiiiiiiimmmmbbb.... then fall back to zero over 3 minutes or so.