Engineer Utility
ISO Metric Coarse
ISO Metric Fine
ISO Metric Conduit
UNC
UNF
BSW
BSF
BSP
BA
PG

BSF British Standard Fine


BS thread - 55° profile


Size TPI Pitch
in		 Ext Major
in		 Int Minor
in		 Tap Drill Size
in		 Tap Drill Size
mm
3/16" 32 0.0310 0.1875 0.1478 0.158 4.0
7/32" 28 0.0360 0.2188 0.1727 0.181 4.6
1/4" 26 0.0390 0.2500 0.2001 0.209 5.3
9/32" 26 0.0390 0.2813 0.2314 0.24 6.1
5/16" 22 0.0460 0.3125 0.2536 0.268 6.8
3/8" 20 0.0500 0.3750 0.3110 0.327 8.3
7/16" 18 0.0560 0.4375 0.3658 0.382 9.7
1/2" 16 0.0630 0.5000 0.4193 0.437 11.1
9/16" 16 0.0630 0.5625 0.4818 0.5 12.7
5/8" 14 0.0710 0.6250 0.5341 0.551 14.0
11/16" 14 0.0710 0.6875 0.5966 0.61 15.5
3/4" 12 0.0830 0.7500 0.6437 0.659 16.7
13/16" 12 0.0830 0.8125 0.7062 0.719 18.3
7/8" 11 0.0910 0.8750 0.7585 0.778 19.8
1" 10 0.1000 1.0000 0.8719 0.896 22.8
1 1/8" 9 0.1110 1.1250 0.9828 1.043 26.5
1 1/4" 9 0.1110 1.2500 1.1078 1.132 28.8
1 3/8" 8 0.1250 1.3750 1.2149 1.24 31.5
1 1/2" 8 0.1250 1.5000 1.3399 1.358 34.5
1 5/8" 8 0.1250 1.6250 1.4649 1.496 38.0
1 3/4" 7 0.1430 1.7500 1.5669 1.595 40.5
2" 7 0.1430 2.0000 1.8169 1.85 47.0
2 1/4" 6 0.1670 2.2500 2.0361 2.087 53.0
2 1/2" 6 0.1670 2.5000 2.2861 2.323 59.0
2 3/4" 6 0.1670 2.7500 2.5361 2.546 64.7
3" 5 0.2000 3.0000 2.7439 2.778 70.6
3 1/4" 5 0.2000 3.2500 2.9939 3.009 76.4
3 1/2" 4.5 0.2220 3.5000 3.2157 3.241 82.3
3 3/4" 4.5 0.2220 3.7500 3.4657 3.472 88.2
4" 4.5 0.2220 4.0000 3.7157 3.704 94.1
4 1/4" 4 0.2500 4.2500 3.9298 3.935 100.0