Threads and Threading - Sportpilot.info
Threads and Threading - Sportpilot.info
Threads and Threading - Sportpilot.info
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WHITWORTH THREADS 1859<br />
Table 3. British St<strong>and</strong>ard Whitworth (BSW) <strong>and</strong> British St<strong>and</strong>ard Fine (BSF) Screw<br />
Thread Series—Basic Dimensions BS 84:1956 (obsolescent)<br />
Nominal<br />
Size,<br />
Inches<br />
<strong>Threads</strong><br />
per<br />
Inch<br />
Machinery's H<strong>and</strong>book 27th Edition<br />
Pitch,<br />
Inches<br />
Depth of<br />
Thread,<br />
Inches<br />
Major<br />
Diameter,<br />
Inches<br />
Effective<br />
Diameter,<br />
Inches<br />
Minor<br />
Diameter,<br />
Inches<br />
Area at Bottom<br />
ofThread,<br />
Sq. in.<br />
Tap<br />
Drill<br />
Dia.<br />
Coarse Thread Series (BSW)<br />
1<br />
⁄8<br />
a 40 0.02500 0.0160 0.1250 0.1090 0.9030 0.0068 2.55 mm<br />
3<br />
⁄16 24 0.04167 0.0267 0.1875 0.1608 0.1341 0.0141 3.70 mm<br />
1<br />
⁄4 20 0.05000 0.0320 0.2500 0.2180 0.1860 0.0272 5.10 mm<br />
5<br />
⁄16 18 0.05556 0.0356 0.3125 0.2769 0.2413 0.0457 6.50 mm<br />
3<br />
⁄8 16 0.06250 0.0400 0.3750 0.3350 0.2950 0.0683 7.90 mm<br />
7<br />
⁄16 14 0.07143 0.0457 0.4375 0.3918 0.3461 0.0941 9.30 mm<br />
1<br />
⁄2 12 0.08333 0.0534 0.5000 0.4466 0.3932 0.1214 10.50 mm<br />
9<br />
⁄16<br />
a 12 0.08333 0.0534 0.5625 0.5091 0.4557 0.1631 12.10. mm<br />
5<br />
⁄8 11 0.09091 0.0582 0.6250 0.5668 0.5086 0.2032 13.50 mm<br />
11<br />
⁄16<br />
a 11 0.09091 0.0582 0.6875 0.6293 0.5711 0.2562 15.00 mm<br />
3<br />
⁄4 10 0.10000 0.0640 0.7500 0.6860 0.6220 0.3039 16.25 mm<br />
7<br />
⁄8 9 0.11111 0.0711 0.8750 0.8039 0.7328 0.4218 19.25 mm<br />
1 8 0.12500 0.0800 1.0000 0.9200 0.8400 0.5542 22.00 mm<br />
1 1 ⁄ 8 7 0.14286 0.0915 1.1250 1.0335 0.9420 0.6969 24.75 mm<br />
1 1 ⁄ 4 7 0.14286 0.0915 1.2500 1.1585 1.0670 0.8942 28.00 mm<br />
1 1 ⁄ 2 6 0.16667 0.1067 1.5000 1.3933 1.2866 1.3000 33.50 mm<br />
1 3 ⁄ 4 5 0.20000 0.1281 1.7500 1.6219 1.4938 1.7530 39.00 mm<br />
2 4.5 0.22222 0.1423 2.0000 1.8577 1.7154 2.3110 44.50 mm<br />
2 1 ⁄ 4 4 0.25000 0.1601 2.2500 2.0899 1.9298 2.9250<br />
2 1 ⁄ 2 4 0.25000 0.1601 2.5000 2.3399 2.1798 3.7320<br />
2 Tap drill diameters<br />
shown in<br />
this column are<br />
recommended<br />
sizes listed in<br />
BS 1157:1975<br />
<strong>and</strong> provide<br />
from 77 to 87%<br />
of full thread.<br />
3 ⁄ 4 3.5 0.28571 0.1830 2.7500 2.5670 2.3840 4.4640<br />
3 3.5 0.28571 0.1830 3.0000 2.8170 2.6340 5.4490<br />
3 1 ⁄ a<br />
4 3.25 0.30769 0.1970 3.2500 3.0530 2.8560 6.4060<br />
3 1 ⁄ 2<br />
3<br />
3.25 0.30769 0.1970 3.5000 3.3030 3.1060 7.5770<br />
3 ⁄ a<br />
4<br />
4<br />
4<br />
3<br />
3<br />
0.33333<br />
0.33333<br />
0.2134<br />
0.2134<br />
3.7500<br />
4.0000<br />
3.5366<br />
3.7866<br />
3.3232<br />
3.5732<br />
8.6740<br />
10.0300<br />
1 ⁄ 2<br />
5<br />
5<br />
2.875<br />
2.75<br />
0.34783<br />
0.36364<br />
0.2227<br />
0.2328<br />
4.5000<br />
5.0000<br />
4.2773<br />
4.7672<br />
4.0546<br />
4.5344<br />
12.9100<br />
16.1500<br />
1 ⁄ 2<br />
6<br />
2.625<br />
2.5<br />
0.38095<br />
0.40000<br />
0.2439<br />
0.2561<br />
5.5000<br />
6.0000<br />
5.2561<br />
5.7439<br />
5.0122<br />
5.4878<br />
19.7300<br />
23.6500<br />
Fine Thread Series (BSF)<br />
3<br />
⁄16<br />
a, b 32 0.03125 0.0200 0.1875 0.1675 0.1475 0.0171 4.00 mm<br />
7<br />
⁄32<br />
a 28 0.03571 0.0229 0.2188 0.1959 0.1730 0.0235 4.60 mm<br />
1<br />
⁄4 26 0.03846 0.0246 0.2500 0.2254 0.2008 0.0317 5.30 mm<br />
9<br />
⁄32<br />
a 26 0.03846 0.0246 0.2812 0.2566 0.2320 0.0423 6.10 mm<br />
5<br />
⁄16 22 0.04545 0.0291 0.3125 0.2834 0.2543 0.0508 6.80 mm<br />
3<br />
⁄8 20 0.05000 0.0320 0.3750 0.3430 0.3110 0.0760 8.30 mm<br />
7<br />
⁄16 18 0.05556 0.0 356 0.4375 0.4019 0.3363 0.1054 9.70 mm<br />
1<br />
⁄2 16 0.06250 0.0400 0.5000 0.4600 0.4200 0.1385 11.10 mm<br />
9<br />
⁄16 16 0.06250 0.0400 0.5625 0.5225 0.4825 0.1828 12.70 mm<br />
5<br />
⁄8 14 0.07143 0.0457 0.6250 0.5793 0.5336 0.2236 14.00 mm<br />
11<br />
⁄16<br />
a 14 0.07143 0.0457 0.6875 0.6418 0.5961 0.2791 15.50 mm<br />
3<br />
⁄4 12 0.08333 0.0534 0.7500 0.6966 0.6432 0.3249 16.75 mm<br />
7<br />
⁄8 11 0.09091 0.0582 0.8750 0.8168 0.7586 0.4520 19.75 mm<br />
1 10 0.10000 0.0640 1.0000 0.9360 0.8720 0.5972 22.75 mm<br />
11 ⁄ 8 9 0.11111 0.0711 1.1250 1.0539 0.9828 0.7586 25.50 mm<br />
11 ⁄ 4 9 0.11111 0.0711 1.2500 1.1789 1.1078 0.9639 28.50 mm<br />
1 3 ⁄ a<br />
8 8 0.12500 0.0800 1.3750 1.2950 1.2150 1.1590 31.50 mm<br />
1 1 ⁄ 2 8 0.12500 0.0800 1.5000 1.4200 1.3400 1.4100 34.50 mm<br />
1 5 ⁄ a<br />
8 8 0.12500 0.0800 1.6250 1.5450 1.4650 1.6860<br />
13 ⁄ 4 7 0.14286 0.0915 1.7500 1.6585 1.5670 1.9280<br />
2<br />
2<br />
7 0.14286 0.0915 2.0000 1.9085 1.8170 2.5930 Tap drill sizes<br />
listed in this<br />
column are<br />
recommended<br />
sizes shown in<br />
BS 1157:1975<br />
<strong>and</strong> provide<br />
from 78 to 88%<br />
of full thread.<br />
1 ⁄ 4<br />
2<br />
6 0.16667 0.1067 2.2500 2.1433 2.0366 3.2580<br />
1 ⁄ 2 6 0.16667 0.1067 2.5000 2.3933 2.2866 4.1060<br />
2 3 ⁄ 4 6 0.16667 0.1067 2.7500 2.6433 2.5366 5.0540<br />
3 5 0.20000 0.1281 3.0000 2.8719 2.7438 5.9130<br />
3 1 ⁄ 4 5 0.20000 0.1281 3.2500 3.1219 2.9938 7.0390<br />
3 1 ⁄ 2<br />
3<br />
4.5 0.22222 0.1423 3.5000 3.3577 3.2154 8.1200<br />
3 ⁄ 4<br />
4<br />
4.5<br />
4.5<br />
0.22222<br />
0.22222<br />
0.1423<br />
0.1423<br />
3.7500<br />
4.0000<br />
3.6077<br />
3.8577<br />
3.4654<br />
3.7154<br />
9.4320<br />
10.8400<br />
41 ⁄ 4 4 0.25000 0.1601 4.2500 4.0899 3.9298 12.1300<br />
a To be dispensed with wherever possible.<br />
b The use of number 2 BA threads is recommended in place of 3/16-inch BSF thread, see page 1885.<br />
Copyright 2004, Industrial Press, Inc., New York, NY
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