3 ms·

Gauge block – the main means of length standardization used by industry

• ddingus 6y ago
  For the precision you get, these are cheap.
• linsomniac 6y ago
  In particular, see the section on Wringing: https://en.wikipedia.org/wiki/Gauge_block#Wringing https://en.wikipedia.org/wiki/Gauge_block#Wringing