Got thinking about all the ways I have of measuring stuff. Put together an array of the metrology items I have for a group picture.

I had a particularly good find recently. This is a Van Keuren "Light Wave" MIcrometer. It reads directly to 'tenths' (1/10000") and has a vernier allowing measurement to 1/100000". Thats 10 millionths of an inch! Readings are highly repeatable because of the pressure indicator that uses a precision gauge block and optical flat. The interference fringes are visible in the picture. You always put the same fringe between the index marks ensuring identical gauging pressure each time.