Steel Rules, Starrett
Starrett precision steel rules are machine-divided, not photoengraved. They are inspected to Starrett Master Standards, which are traceable to the National Institute of Standards and Technology.
Graduation No. 4R are 8ths, 16ths, quick-reading 32nds and 64ths.
Graduation No. 16R are Quick-reading 32nds and 64ths, aircraft quick-reading 50ths and 100ths.
Graduation No. 5R are quick-reading 10ths, aircraft quick-reading 100ths, 32nds and 64ths.
Graduations No. 31 are 32nds and 64ths on one side; mm and 1/2 mm on reverse.
Flexible rules are 1/2" wide and 1/64" thick.
Rigid rules are 3/4" wide and 3/64" thick.
Chris' Tips
When using a precision rule for very close accuracy, the eye can read better by measuring between two lines than from the end of the rule to a line. Here is how to use a steel rule.