JB/T 10006-2018 "Internal Measurement Micrometer" specifies the terms and definitions, types and basic parameters, requirements, inspection conditions, inspection methods, signs and Encasement of internal measurement Micrometer. This standard applies to internal measurement Micrometer with scale interval of 0.01 mm (resolution of 0.001 mm), micrometer screw pitch of 0.5 mm, micrometer head range of 25 mm, Measurement range up to 300 mm Scale reading and digital reading (excluding electronic digital display). The standard covers a variety of inner diameter measurement needs. Using the principle of spiral pair, radial adjustment is made by moving the measurement claw to accurately measure the inner diameter size of the measured object.