Threads and Threading - Sportpilot.info

Pitch
P
BRITISH STANDARD ISO METRIC SCREW THREADS 1815
Table 1. (Continued) British Standard ISO Metric Screw Threads
Basic Profile Dimensions BS 3643:1981 (1998)
0.7 0.606 218 0.378 886 0.227 322 0.151 554 0.075 777
0.75 0.649 519 0.405 949 0.243 570 0.162 380 0.081 190
0.8 0.692 820 0.433 013 0.259 808 0.173 205 0.086 603
1 0.866 025 0.541 266 0.324 760 0.216 506 0.108 253
1.25 1.082 532 0.676 582 0.405 949 0.270 633 0.135 316
1.5 1.299 038 0.811 899 0.487 139 0.324 760 0.162 380
1.75 1.515 544 0.947 215 0.568 329 0.378 886 0.189 443
2 1.732 051 1.082 532 0.649 519 0.433 013 0.216 506
2.5 2.165 063 1.353 165 0.811 899 0.541 266 0.270 633
3 2.598 076 1.623 798 0.974 279 0.649 519 0.324 760
3.5 3.031 089 1.894 431 1.136 658 0.757 772 0.378 886
4 3.464 102 2.165 063 1.299 038 0.866 025 0.433 013
4.5 3.897 114 2.435 696 1.461 418 0.974 279 0.487 139
5 4.330 127 2.706 329 1.623 798 1.082 532 0.541 266
5.5 4.763 140 2.976 962 1.786 177 1.190 785 0.595 392
6 5.196 152 3.247 595 1.948 557 1.299 038 0.649 519
8 a 6.928 203 4.330 127 2.598 076 1.732 051 0.866 025
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 combination
of a tolerance grade (figure) and a tolerance position (letter). The tolerance position
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
H =
5
⁄8H = 3
⁄8H = H/4 = H/8 =
0.086603P 0.54127P 0.32476P 0.21651P 0.10825P
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
EI EI es es es es
Pitch
P
EI EI es es es es
mm µm µm µm µm µm µm mm µm µm µm µm µm µm
0.2 +17 0 … … −17 0 1.25 +28 0 −63 −42 −28 0
0.25 +18 0 … … −18 0 1.5 +32 0 −67 −45 −32 0
0.3 +18 0 … … −18 0 1.75 +34 0 −71 −48 −34 0
0.35 +19 0 … −34 −19 0 2 +38 0 −71 −52 −38 0
0.4 +19 0 … −34 −19 0 2.5 +42 0 −80 −58 −42 0
0.45 +20 0 … −35 −20 0 3 +48 0 −85 −63 −48 0
0.5 +20 0 −50 −36 −20 0 3.5 +53 0 −90 −70 −53 0
0.6 +21 0 −53 −36 −21 0 4 +60 0 −95 −75 −60 0
0.7 +22 0 −56 −38 −22 0 4.5 +63 0 −100 −80 −63 0
0.75 +22 0 −56 −38 −22 0 5 +71 0 −106 −85 −71 0
0.8 +24 0 −60 −38 −24 0 5.5 +75 0 −112 −90 −75 0
1 +26 0 −60 −40 −26 0 6 +80 0 −118 −95 −80 0
See Figs. 1 and 2 for meaning of symbols.
Machinery's Handbook 27th Edition
Nut Thread
D 2, D 1
Copyright 2004, Industrial Press, Inc., New York, NY
Bolt Thread
d, d 2