Machinery's Handbook, 31st Edition
British Standard ISO Metric Screw Threads 2045 Table 1. British Standard ISO Metric Screw Threads Basic Profile Dimensions BS 3643:1981 (R2004) Table 1. (Continued) British Standard ISO Metric Screw Threads Basic Profile Dimensions BS 3643:1981 (R2004)
Pitch P
H = 0.86603 P 0.649 519 0.692 820 0.866 025 1.082 532 1.299 038 1.515 544 1.732 051 2.165 063 2.598 076 3.031 089 3.464 102 3.897 114 4.330 127 4.763 140 5.196 152 6.928 203
5 ∕ 8 H = 0.54127 P 0.405 949 0.433 013 0.541 266 0.676 582 0.811 899 0.947 215 1.082 532 1.353 165 1.623 798 1.894 431 2.165 063 2.435 696 2.706 329 2.976 962 3.247 595 4.330 127
3 ∕ 8 H = 0.32476 P 0.243 570 0.259 808 0.324 760 0.405 949 0.487 139 0.568 329 0.649 519 0.811 899 0.974 279 1.136 658 1.299 038 1.461 418 1.623 798 1.786 177 1.948 557 2.598 076
H /4 = 0.21651 P 0.162 380 0.173 205 0.216 506 0.270 633 0.324 760 0.378 886 0.433 013 0.541 266 0.649 519 0.757 772 0.866 025 0.974 279 1.082 532 1.190 785 1.299 038 1.732 051
H /8 = 0.10825 P 0.081 190 0.086 603 0.108 253 0.135 316 0.162 380 0.189 443 0.216 506 0.270 633 0.324 760 0.378 886 0.433 013 0.487 139 0.541 266 0.595 392 0.649 519 0.866 025
0.75 0.8 1.25 1.5 1.75 1
2
2.5
3
3.5
4
4.5
5
5.5
6
8 a
a This pitch is not used in any of the ISO metric standard series. All dimensions are given in millimeters.
Tolerance System.— The tolerance system defines tolerance classes in terms of a combi nation of a tolerance grade (figure) and a tolerance position (letter). The tolerance posi- tion is defined by the distance between the basic size and the nearest end of the tolerance zone, this distance being known as the fundamental deviation, EI, in the case of internal threads, and es in the case of external threads. These tolerance positions with respect to the basic size (zero line) are shown in Fig. 2 and fundamental deviations for nut and bolt threads are given in Table 2. Table 2. Fundamental Deviations for Nut Threads and Bolt Threads
Nut Thread D 2 , D 1
Nut Thread D 2 , D 1
Bolt Thread d , d 2
Bolt Thread d , d 2
Tolerance Position
Tolerance Position
G H e
f
g
h
G H e
f
g
h
Fundamental Deviation
Fundamental Deviation
Pitch P mm
Pitch P mm
EI
EI
es
es
es
es
EI
EI
es
es
es
es
μ m
μ m
μ m
μ m
μ m
μ m
μ m
μ m
μ m − 63 − 67 − 71 − 71 − 80 − 85 − 90
μ m − 42 − 45 − 48 − 52 − 58 − 63 − 70 − 75 − 80 − 85 − 90 − 95
μ m
μ m
0.2 +17 0 0.25 +18 0 0.3 +18 0 0.35 +19 0 0.4 +19 0 0.45 +20 0 0.5 +20 0 0.6 +21 0 0.7 +22 0 0.75 +22 0 0.8 +24 0
… … … … … …
1.25 +28 0 1.5 +32 0 1.75 +34 0
− 17 0 − 18 0 − 18 0 − 19 0 − 19 0 − 20 0 − 20 0 − 21 0 − 22 0 − 22 0 − 24 0 − 26 0
− 28 0 − 32 0 − 34 0 − 38 0 − 42 0 − 48 0 − 53 0 − 60 0 − 63 0 − 71 0 − 75 0 − 80 0
… … …
2
+38 0
− 34 − 34 − 35 − 36 − 36 − 38 − 38 − 38 − 40
2.5 +42 0
3
+48 0
3.5 +53 0
− 50 − 53 − 56 − 56 − 60 − 60
4
+60 0
− 95 − 100 − 106 − 112 − 118
4.5 +63 0
5
+71 0
5.5 +75 0
1
+26 0
6
+80 0
See Fig. 1 and Fig. 2 for meaning of symbols.
Copyright 2020, Industrial Press, Inc.
ebooks.industrialpress.com
Made with FlippingBook - Share PDF online