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
Current Document Icon Unified Fine
Document Icon British Association
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

Unified Fine

Thread Form

Unified Thread Form
  • p = Pitch = 1/TPI
  • hn = Height of internal thread = 0.54127p
  • hs = Height of external thread = 0.61344p
  • r = Basic Radius = 0.1443p

Thread Tables

Nominal Size T.P.I. Basic Major Diameter Basic Effective Diameter Basic Minor Diameter of External Threads Basic Minor Diameter of Internal Threads Tapping Drill Clearance Drill
(n/a) (n/a) (inch) (inch) (inch) (inch) (mm) (mm)
No. 0 80 0.06 0.0519 0.0447 0.0465 1.25 1.6
No. 1 72 0.073 0.064 0.056 0.058 1.55 1.96
No. 2 64 0.086 0.0759 0.0668 0.0691 1.9 2.3
No. 3 56 0.099 0.0874 0.0771 0.0797 2.15 2.65
No. 4 48 0.112 0.0985 0.0864 0.0894 2.4 2.95
No. 5 44 0.125 0.1102 0.0971 0.1004 2.7 3.3
No. 6 40 0.138 0.1218 0.1073 0.1109 2.95 3.6
No. 8 36 0.164 0.146 0.1299 0.1339 3.5 4.3
No. 10 32 0.19 0.1697 0.1517 0.1562 4.1 4.9
No. 12 28 0.216 0.1928 0.1722 0.1773 4.7 5.6
1/4 28 0.25 0.2268 0.2062 0.2113 5.5 6.5
5/16 24 0.3125 0.2854 0.2614 0.2674 6.9 8.1
3/8 24 0.375 0.3479 0.3239 0.3299 8.5 9.7
7/16 20 0.4375 0.405 0.3762 0.3834 9.9 11.3
1/2 20 0.5 0.4675 0.4387 0.4459 11.5 13
9/16 18 0.5625 0.5264 0.4943 0.5024 12.9 14.5
5/8 18 0.625 0.5889 0.5568 0.5649 14.5 16.25
3/4 16 0.75 0.7094 0.6733 0.6823 17.5 19.25
7/8 14 0.875 0.8286 0.7874 0.7977 20.4 22.5
1 12 1 0.9459 0.8978 0.9098 23.25 25.75
1, 1/8 12 1.125 1.0709 1.0228 1.0348 26.5 29
1, 1/4 12 1.25 1.1959 1.1478 1.1598 29.5 32
1, 3/8 12 1.375 1.3209 1.2728 1.2848 32.75 35.5
1, 1/2 12 1.5 1.4459 1.3978 1.4098 36 38.5
Copyright © Solid Fluid 2007-2022
Last modified: SolFlu  Fri, 26 Jun 2009 21:15:35 GMT