Solid Fluid System Solutions  
Home Software About Hardware Firmware
Document Icon ISO Metric Coarse
Document Icon ISO Metric Fine
Document Icon ISO Metric Special
Document Icon Unified Coarse
Document Icon Unified Fine
Document Icon British Association
Current Document Icon British Standard Fine
Document Icon British Standard Brass
Document Icon British Standard Cycle
Document Icon British Standard Whitworth
Document Icon Model Engineer
Document Icon Reverse Lookup

British Standard Fine (B.S.F.)

Thread Form

BSF Thread Form
  • p = Pitch = 1/TPI
  • h = Basic Depth of Thread = 0.640327p
  • r = Basic Radius = 0.137329p

Thread Tables

Nominal Diameter T.P.I. Basic Depth of Thread Basic Major Diameter Basic Effective Diameter Basic Minor Diameter Tapping Drill Clearing Drill
(inch) (n/a) (inch) (inch) (inch) (inch) (mm) (mm)
3/16 32 0.02 0.1875 0.1675 0.1475 4 4.9
7/32 28 0.0229 0.2188 0.1959 0.173 4.6 5.7
1/4 26 0.0246 0.25 0.2254 0.2008 5.3 6.5
5/16 22 0.0291 0.3125 0.2834 0.2543 6.8 8.1
3/8 20 0.032 0.375 0.343 0.311 8.3 9.7
7/16 18 0.0356 0.4375 0.4019 0.3663 9.7 11.3
1/2 16 0.04 0.5 0.46 0.42 11.1 13
9/16 16 0.04 0.5625 0.5225 0.4825 12.7 14.5
5/8 14 0.0457 0.625 0.5793 0.5336 14 16.25
11/16 14 0.0457 0.6875 0.6418 0.5961 15.5 17.75
3/4 12 0.0534 0.75 0.6966 0.6432 16.75 19.25
7/8 11 0.0582 0.875 0.8168 0.7586 19.75 22.5
1 10 0.064 1 0.936 0.872 22.75 25.75
1,1/8 9 0.0711 1.125 1.0539 0.9828 25.5 29
1,1/4 9 0.0711 1.25 1.1789 1.1078 28.5 32
1,3/8 8 0.08 1.375 1.295 1.215 31.5 35.5
1,1/2 8 0.08 1.5 1.42 1.34 34.5 38.5
1,3/4 7 0.0915 1.75 1.6585 1.567 41 45
2 7 0.0915 2 1.9085 1.817 47 52
2,1/4 6 0.1067 2.25 2.1433 2.0366 53 58
2,1/2 6 0.1067 2.5 2.3933 2.2866 58 64
Copyright © Solid Fluid 2007-2015
Last modified: SolFlu  Sun, 28 Jun 2009 02:58:13 GMT