Machinery's Handbook, 31st Edition
British Standard ISO Metric Screw Threads 2049 Crest Diameter Tolerance Formulas.— The tolerances for the major diameter of bolt threads ( T d ), grade 6, in Table 5 , were calculated from the formula: . T P P 6 180 315 d 3 2 = − ^ h In this formula, T d (6) is in micrometers and P is in millimeters. For tolerance grades 4 and 8: T d (4) = 0.63 T d (6) and T d (8) = 1.6 T d (6), respectively. The tolerances for the minor diameter of nut threads ( T D 1 ), grade 6, in Table 5, were cal culated as follows: For pitches 0.2 to 0.8 mm, T D 1 (6) = 433 P − 190 P 1.22 . For pitches 1 mm and coarser, T D 1 (6) = 230 P 0.7 . In these formulas, T D 1 (6) is in micrometers and P is in millimeters. For tolerance grades 4, 5, 7, and 8: T D 1 (4) = 0.63 T D 1 (6); T D 1 (5) = 0.8 T D 1 (6); T D 1 (7) = 1.25 T D 1 (6); and T D 1 (8) = 1.6 T D 1 (6), respectively. Table 5. British Standard ISO Metric Screw Threads: Limits and Tolerances for Finished Uncoated Threads for Normal Lengths of Engagement BS 3643: Part 2: 1981 Pitch External Threads (Bolts) Internal Threads (Nuts) b Fund dev. Major Dia. Pitch Dia. Minor Dia Major Dia. Pitch Dia. Minor Dia Max Tol( − ) Max Tol( − ) Min Min Max Tol( − ) Max Tol( − )
1.000 0.036 0.870 0.030 0.717 4H 1.000 0.910 0.040 0.821 0.038
0.2 4h 0
6g 0.017 0.983 0.056 0.853 0.048 0.682
1
4h 0 1.000 0.042 0.838 0.034 0.649 4H 1.000 0.883 0.045 0.774 0.045 6g 0.018 0.982 0.067 0.820 0.053 0.613 5H 1.000 0.894 0.056 0.785 0.056
0.25
1.100 0.036 0.970 0.030 0.817 4H 1.100 1.010 0.040 0.921 0.038
0.2 4h 0
6g 0.017 1.083 0.056 0.953 0.048 0.782
1.1
4h 0 1.100 0.042 0.938 0.034 0.750 4H 1.100 0.983 0.045 0.874 0.045 6g 0.018 1.082 0.067 0.920 0.053 0.713 5H 1.100 0.994 0.056 0.885 0.056
0.25
1.200 0.036 1.070 0.030 0.917 4H 1.200 1.110 0.040 1.021 0.038
0.2 4h 0
6g 0.017 1.183 0.056 1.053 0.048 0.882
1.2
4h 0 1.200 0.042 1.038 0.034 0.850 4H 1.200 1.083 0.045 0.974 0.045 6g 0.018 1.182 0.067 1.020 0.053 0.813 5H 1.200 1.094 0.056 0.985 0.056
0.25
1.400 0.036 1.270 0.030 1.117 4H 1.400 1.310 0.040 1.221 0.038
0.2 4h 0
6g 0.017 1.383 0.056 1.253 0.048 1.082
1.4
4h 0 1.400 0.048 1.205 0.036 0.984 4H 1.400 1.253 0.048 1.128 0.053 6g 0.018 1.382 0.075 1.187 0.056 0.946 5H 1.400 1.265 0.060 1.142 0.067 6H 1.400 1.280 0.075 1.160 0.085
0.3
1.600 0.036 1.470 0.032 1.315 4H 1.600 1.512 0.042 1.421 0.038
0.2 4h 0
6g 0.017 1.583 0.056 1.453 0.050 1.280
1.6
4h 0 1.600 0.053 1.373 0.040 1.117 4H 1.600 1.426 0.053 1.284 0.063 6g 0.019 1.581 0.085 1.354 0.063 1.075 5H 1.600 1.440 0.067 1.301 0.080 6H 1.600 1.458 0.085 1.321 0.100
0.35
1.800 0.036 1.670 0.032 1.515 4H 1.800 1.712 0.042 1.621 0.038
0.2 4h 0
6g 0.017 1.783 0.056 1.653 0.050 1.480
1.8
4h 0 1.800 0.053 1.573 0.040 1.317 4H 1.800 1.626 0.053 1.484 0.063 6g 0.019 1.781 0.085 1.554 0.063 1.275 5H 1.800 1.640 0.067 1.501 0.080 6H 1.800 1.658 0.085 1.521 0.100 2.000 0.042 1.838 0.036 1.648 4H 2.000 1.886 0.048 1.774 0.045 6g 0.018 1.982 0.067 1.820 0.056 1.610 5H 2.000 1.898 0.060 1.785 0.056 4h 0 2.000 0.060 1.740 0.042 1.452 4H 2.000 1.796 0.056 1.638 0.071 6g 0.019 1.981 0.095 1.721 0.067 1.408 5H 2.000 1.811 0.071 1.657 0.090 6H 2.000 1.830 0.090 1.679 0.112 2.200 0.042 2.038 0.036 1.848 4H 2.200 2.086 0.048 1.974 0.045 6g 0.018 2.182 0.067 2.020 0.056 1.810 5H 2.200 2.098 0.060 1.985 0.056 4h 0 2.200 0.063 1.908 0.045 1.585 4H 2.200 1.968 0.060 1.793 0.080 6g 0.020 2.180 0.100 1.888 0.071 1.539 5H 2.200 1.983 0.075 1.813 0.100 6H 2.000 2.003 0.095 1.838 0.125 2.500 0.053 2.273 0.040 2.017 4H 2.500 2.326 0.053 2.184 0.063 6g 0.019 2.481 0.085 2.254 0.063 1.975 5H 2.500 2.340 0.067 2.201 0.080 6H 2.500 2.358 0.085 2.221 0.100 4h 0 4h 0 2.500 0.063 2.208 0.045 1.885 4H 2.500 2.268 0.060 2.093 0.080 6g 0.020 2.480 0.100 2.188 0.071 1.839 5H 2.500 2.283 0.075 2.113 0.100 6H 2.500 2.303 0.095 2.138 0.125
0.35
0.25 4h 0
2
0.4
0.25 4h 0
2.2
0.45
0.35
2.5
0.45
Copyright 2020, Industrial Press, Inc.
ebooks.industrialpress.com
Made with FlippingBook - Share PDF online