The micrometer and the act of using it. An outside mic reads to a thou on the thimble and to a tenth with a vernier or digital readout, over a one inch range per frame. Consistent feel is everything, so the ratchet or friction thimble is used to apply the same pressure each time, and the zero is checked against the standard before measuring anything tight.
Mic it in three places along the length, if it's tapered more than a tenth the tailstock is out.
Never spin a mic open or closed by its frame like a yo-yo; it wears the threads and the old hands will notice.
Also heard as
- mike
- micrometer
Related terms
Thou
One thousandth of an inch (0.001 in, about 25 microns), the everyday unit of machining talk in inch shops.
Tenth
One ten-thousandth of an inch (0.0001 in, about 2.5 microns), the unit of precision grinding and fits.
Dead nuts
Shop slang for exactly on size or perfectly aligned, with no measurable error left.
Jo blocks
Shop name for gauge blocks: lapped steel or ceramic blocks, accurate to millionths, stacked to make any length.