Micrometer only reads to .1 inches? A micrometer screw thread is 40 tpi or 1 turn =.1 of 1/4 inch =.025 inches. Just by counting turns you can get that accurate. There are 25 division around te barrel meaing that each division = .001 inches. My Starret has a vernier scale which further divides each into 10 making it readable to .0001 inches