The Mitutoyo 516-331-26 micrometer inspection gage block set includes nine ASME grade AS-1 ceramic rectangular gage blocks with nominal size engraved in inches.
Blocks included in the set measure .0625, .100, .125, .200, .250, .300, .500, 1, and 2”. Grade AS-1 gage blocks are often used for calibrating and inspecting tools, instruments, and manufacturing gages.
Gage blocks (also called gauge blocks, Jo blocks, Hoke blocks, and Johansson gauges) are precision ground and lapped metal or ceramic blocks, used for calibrating precision measuring equipment and as a length standard in manufacturing. Gage blocks are square or rectangular in shape, with flat and parallel measuring surfaces, and usually have an engraved unique serial number and nominal length (provided in either inches or millimeters). They often come in sets with blocks of varying lengths, so that many different standard lengths can be created by stacking and wringing them. Wringing is the process of sliding blocks together with a small amount of pressure, in order to create a longer gage block stack.
Gage blocks are kept within a protective case, are cleaned thoroughly before wringing and after each use to prevent corrosion, and are kept free of burrs and other damage that would decrease their accuracy. Temperature is another important consideration. Blocks are susceptible to thermal expansion and must be used at 68 degrees F to ensure their accuracy.
Gage blocks are available in different grades, which refer to their tolerance or allowable deviation from their nominal dimension. Grades are defined by the American Society of Mechanical Engineers (ASME) B89.1.9M for both length and flatness. ASME B89.1.9M also defines standards for parallelism and surface finish. Different grades are available depending on the application and the required level of accuracy. Grade 00 blocks are generally used to calibrate and check the accuracy of instruments, grade 0 blocks for setting and checking gages in quality control, grade AS-1 blocks for tool rooms and production purposes, and grade AS-2 are similar to AS-1 blocks but are slightly less accurate. Grade K blocks are used for calibrating and checking the accuracy of other gage blocks within a temperature-controlled inspection or calibration room. A certificate of inspection and calibration is provided with each gage block or set, specifying the deviation of the individual block from its nominal length.
Founded in Tokyo in 1934, Mitutoyo is a leader in the metrology field, producing high-quality measurement products including mechanical, dimensional gauging products, focusing on micrometers, calipers, indicators, and other measurement tools, as well as output gauges, interfaces, data collectors, and analysis software. Mitutoyo formed Mitutoyo America Corporation in 1963, which is headquartered in Aurora, Illinois, with additional locations in the U.S. and Canada.