SHARS PRECISION 4-5 INCH BLADE OUTSIDE MICROMETER. This micrometer is manufactured in a state-of-the-art ISO 9001 certified facility filled with modern machines such as Haas CNC milling centers, Brother CNC milling centers, Haas CNC turning centers just a few examples on the 50,000 sq. Each micrometer is checked at 10 data points for maximum error tolerance with high precision gage blocks and also conducted inspection on parallelism and flatness by optical flat in a strict temperature controlled environment. The critical benchmark inspection media such as gage block are inspected periodically on world-known Swiss made calibration machines such as Switzerland’s Trimos’s Universal Gage Calibration System model Labortory500 and Germany’s Carl Zeiss Jena model 0-3000 mm calibration system for oversized length calibration. Trimos’s Universal Gage Calibration System model Labortory500. The anvil and spindle have a blade for measuring the groove diameter of shafts, keyways, and other hard-to-reach areas. Heat insulated frame with baked enamel finished. 030; blade width =. 236; blade penetration =. Clear graduation on satin chrome finish on spindle sleeve to increase readability. Non-rotating spindle design in hardened and precision ground lead screw threads give reliable and accurate reading. Rotating the thimble sleeve when the inspection piece is between the spindle and anvil activate the ratchet mechanism to tap the spindle and apply uniform measuring force to the inspection piece. Also easier to use in one-hand operation and improves measurement repeatability than ratchet-stop style micrometer.