Machinery's Handbook, 31st Edition
722
Gage Blocks Table 1b. Maximum Permitted Deviations of Length at Any Point a and Tolerance on Variation in Length, Metric b ANSI/ASME B89.1.9-2002 (R2012)
Calibration Grade K Grade 00
Grade 0
Grade AS-1
Grade AS-2
Nominal Length Range, l n mm
± t e μm
t v μm
± t e μm
t v μm
± t e μm
t v μm
± t e μm
t v μm
± t e μm
t v μm
≤ 0.5
0.30 0.20 0.30 0.40 0.50 0.60 0.80 1.00 1.20 1.40 1.80 2.20 2.60 3.00 3.40 3.80 4.20
0.10 0.07 0.10 0.12 0.15 0.20 0.25 0.30 0.35 0.45 0.50 0.65 0.75 0.85 0.95 1.00
0.14 0.12 0.14 0.20 0.25 0.30 0.40 0.50 0.60 0.70 0.90 1.10 1.30 1.50 1.70 1.90 2.00
0.30 0.20 0.30 0.40 0.50 0.60 0.80 1.00 1.20 1.40 1.80 2.20 2.60 3.00 3.40 3.80 4.20
0.60 0.45 0.60 0.80 1.00 1.20 1.60 2.00 2.40 2.80 3.60 4.40 5.00 6.00 6.50 7.50 8.00
0.5 < l n ≤ 10 10 < l n ≤ 25 25 < l n ≤ 50 50 < l n ≤ 75
0.05
0.05
0.16
0.10
0.30
0.06 0.07 0.08 0.09 0.10 0.12 0.14 0.16 0.18 0.20 0.25
0.06 0.07 0.08 0.09 0.10 0.12 0.14 0.16 0.18 0.20 0.25
0.18
0.12 0.14 0.16 0.18 0.20 0.25 0.30 0.35 0.40
0.35
75 <
l n ≤ 100
0.20
100 < l n ≤ 150
0.40 0.45 0.50 0.60 0.70 0.80 0.90 1.00
l n ≤ 200
150 <
200 < l n ≤ 250 250 < l n ≤ 300 400 < l n ≤ 500 500 < l n ≤ 600 300 < l n ≤ 400 700 < l n ≤ 800 800 < l n ≤ 900 900 < l n ≤ 1000 600 < l n ≤ 700
0.25
0.30 0.35 0.40 0.45 0.50 0.60
a Maximum permitted deviations of length at any point, ± t
e μm, from nominal length, l e mm.
b Tolerance, t v μm, for the variation in length. 1) Always keep gage blocks clean and well oiled when not in direct use. Alcohol is acceptable as a cleaner, but it is always advisable to coat the gage block with a rust inhibitor when placing it back in the case. A very light machine oil is recommended. 2) Take great care when removing gage blocks from the case so as not to nick or damage the working surface. Clean with a soft cloth or chamois and isopropanol. Never touch gage blocks with bare hands. Oil from fingers will cause corrosion on the bare metal surface. 3) Always keep the gage blocks over a soft cloth or chamois when handling or wringing them together. Dropping the gage blocks onto a hard surface or other gage blocks will damage the working surface and cause an error beyond the limits of the tolerance. Always treat gage blocks as highly accurate precision instruments. 4) Should the gage block surface show signs of degradation and the wringing together of blocks become difficult, the surface may need to be deburred. The use of a serrated sintered aluminum oxide deburring stone is recommended to recondition the surface and renew the ability to join the gage blocks through wringing. Caution must be exercised when deburr ing the surface of gage blocks so it is not damaged instead of repaired. 5) Gently place the gage block flat on the serrated block. With two fingers (using gloves), press down firmly, but not hard, on the gage block and slide it lengthwise over the serra tions on the block for three or four strokes until the surface feels very smooth. Turn the gage block over and repeat the movement. Remove and clean the gage block thoroughly. 6) It is important that the serrated sintered aluminum oxide deburring stone is cleaned as well, and metal deposits, oils, and dirt are not allowed to build up on the surface. A cotton packing impregnated with a metal solvent will clean the serrated sintered aluminum oxide deburring stone. Calibration and Verification of Gage Blocks.— The calibration and verification of gage blocks should be completed on a regular basis. This is done to maintain measurement assurance in every good quality program. The quality assurance program will determine
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