E-4EMitutoyo reserves the right to change any or all aspects of any product specication, including prices, designs and service content, without notice.(9) Difference in expansion coefcient between steel and CERA blocks is just 1.5×10-6/KThe thermal expansion coefcient of a CERA Block is quite similar to that of a steel gauge block.(10) Highly Resistant to Dropping and Impact DamageThe CERA Block material is one of the toughest ceramics. It is extremely difcult to crack a CERA Block in normal use.Mitutoyo offers extra-thin gauge blocks from 0.10 mm to 0.99 mm (increments of 0.01 mm) as well as long gauge blocks up to 1,000 mm as standard products.(1) Gauge blocks in a stack can be clamped togetherAfter wringing square gauge blocks, a tie rod can be inserted through the center hole to clamp the blocks together for extra security.(2) A height reference standard can easily be made A precision height reference standard can be made easily and inexpensively using accessories such as the plain jaw and block base.(3) A dedicated inspection jig can easily be made A dedicated inspection jig for periodic inspection of instruments can be made easily and inexpensively.(4) A wide measuring surface with cross-sectional dimensions of 24.1×24.1 mm is available. A square gauge block retains stable orientation both longitudinally and laterally. A wide range of applications is covered, including cutting tool positioning, angle measurement with a sine bar, taper measurement with a roller, and inspection of depth micrometers.Features of Square Gauge BlocksLong and Ultra-Thin Gauge BlocksDifference in dimension (µm)3Tungsten carbideCERA BlockDifferences in size between alternative gauge block materials and steel that are obtained when measuring over a length of 100 mm at each temperature.Temperature (°C)2119202122231817–1–2–3(8) Superior Material Characteristics of CERA BlockMaterialPropertyCERA Block(ZrO2)Steel (Fe)Tungsten Carbide(WC-Co)ZERO CERA Blocks(Low thermal expansion)Hardness (HV)13508001650826Coefcient of thermal expansion (10-6/K) 9.3±0.510.8±0.55.5±1.00±0.02Flexural strength by 3-point bending (MPa)127019601960210Fracture toughness K1c (MPa·m1/2)7120121.2Young’s modulus ×104 (MPa)20.620.661.8130Poisson’s ratio0.30.30.20.3Specic gravity6.07.814.82.5Thermal conductivity (W/m·k)2.954.479.53.7Note: Ceramics have the advantage of a slow response to temperature changes due to the low thermal conductivity. However, caution is required when using CERA blocks under conditions of rapid temperature change. Mitutoyo Gauge Blocks and Inspection CerticatesA Certicate of Inspection is furnished with all Mitutoyo gauge blocks with a serial number on the box (in the case of sets) and an identication number on each block. The deviation of each block from nominal length, at the time of inspection, is stated. For this inspection, each gauge block is measured relative to the upper level master using a gauge block comparator. Grade K gauge blocks are measured by a primary measurement method using an interferometer.The following table can be used to select the gauge block grade according to usage (specied by DIN861, BS4311, and JIS B 7506).Grade and ApplicationApplicationsGradeWorkshop use• Mounting tools and cutters2• Manufacturing gages• Calibrating instruments1 or 2Inspection use• Inspecting mechanical parts, tools, etc.1 or 2• Checking the accuracy of gages• Calibrating instruments0 or 1Calibration use• Checking the accuracy of gauge blocks for workshop• Checking the accuracy of gauge blocks for inspection• Checking the accuracy of instrumentsK or 0Reference use• Checking the accuracy of gauge blocks for calibration• For academic researchKConstructing a Gauge Block StackThe following points should be noted when constructing a gauge block stack:(1) Use as few gauge blocks as possible to obtain the required length by selecting thick blocks wherever possible.(2) Select the block for the least signicant digit rst, then work back through the more signicant digits until the required length is attained.(3) There are multiple combinations for the integer part of a length. To prevent wear as much as possible, do not always use the same gauge blocks.Example: Required length=45.6785 mm• For a 1 mm-based gauge block set 1.00051.0081.1717.5 + )2545.6785 mm• For a 2 mm-based gauge block set 2.00052.0082.1714.5 + )2545.6785 mmNote: Regarding the method for wringing, refer to “Quick Guide to Precision Measuring Instruments” on page E-33.
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