1 Blocks from .050". 10 Blocks from .1000" to .1009". 9 Blocks from .101" to .109". 9 Blocks from .110" to .190". 4 Blocks from .200" to .500". 3 Blocks: 1.000", 2.000", 4.000". Grades and Tolerances (Length) [Maximum permissible errors. Units = 1 millionth of an inch] Size of Gauge Up to and including 1" +4 -2, 2" +8 -4, 3" +10 -5, 4" +12 -6