Unified Thread Tables

By Rob Siegwart
Category: Engineering Reference
Tags: bolting

Thread tables for Unified coarse and fine threads along with tensile area and equivalent tensile area diameter per equation A-3-7 from Ref [2]. Tap drills are for 75% thread engagement, per Tables 3 and 4 of Ref [1] of section "Threading".

UNC

Size, Number or Inches Basic Major Diameter (in) TPI Tensile Area, in2 Tensile Area Diameter, in Tap Drill No Tap Drill Size, in Clearance Drill (Close) Clearance Size (Close), in Clearance Drill (Free) Clearance Size (Free), in
0 0.0600 52 0.0635 50 0.07
1 0.0730 64 0.0026 0.058 53 0.0595 48 0.076 46 0.081
2 0.0860 56 0.0037 0.069 50 0.07 43 0.089 41 0.096
3 0.0990 48 0.0049 0.079 47 0.0785 37 0.104 35 0.11
4 0.1120 40 0.0060 0.088 43 0.089 32 0.116 30 0.1285
5 0.1250 40 0.0080 0.101 38 0.1015 30 0.1285 29 0.136
6 0.1380 32 0.0091 0.108 36 0.1065 27 0.144 25 0.1495
8 0.1640 32 0.0140 0.134 29 0.136 18 0.1695 16 0.177
10 0.1900 24 0.0175 0.149 25 0.1495 9 0.196 7 0.201
12 0.2160 24 0.0242 0.175 16 0.177 2 0.221 1 0.228
1/4 0.25 20 0.0318 0.201 7 0.201 F 0.257 H 0.266
5/16 0.3125 18 0.0524 0.258 F 0.257 P 0.323 Q 0.332
3/8 0.375 16 0.0775 0.314 5/16 0.3125 W 0.386 X 0.397
7/16 0.4375 14 0.1063 0.368 U 0.368 29/64 0.4531 15/32 0.4687
1/2 0.5 13 0.1419 0.425 27/64 0.4219 33/64 0.5156 17/32 0.5312
9/16 0.5625 12 0.1819 0.481 31/64 0.4844
5/8 0.625 11 0.2260 0.536 17/32 0.5312
3/4 0.75 10 0.3345 0.653 21/32 0.6562
7/8 0.875 9 0.4617 0.767 49/64 0.7656
1 1 8 0.6057 0.878 7/8 0.875
1 1/8 1.125 7 0.7633 0.986 63/64 0.9844
1 1/4 1.25 7 0.9691 1.111 1 7/64 1.1094
1 5/16 1.3125 7 1.0812 1.173
1 3/8 1.375 6 1.1549 1.213 1 7/32 1.2187
1 1/2 1.5 6 1.4052 1.338 1 11/32 1.3437
1 5/8 1.625 6 1.6802 1.463
1 3/4 1.75 5 1.8995 1.555 1 9/16 1.5625
1 7/8 1.875 5 2.2171 1.680 1 11/16 1.6875
2 2 4.5 2.4982 1.783 1 25/32 1.7812
2 1/4 2.25 4.5 3.2477 2.033 2 1/32 2.0312
2 1/2 2.5 4 3.9988 2.256 2 1/4 2.25
2 3/4 2.75 4 4.9340 2.506
3 3 4 5.9674 2.756
3 1/4 3.25 4 7.0989 3.006
3 1/2 3.5 4 8.3286 3.256
3 3/4 3.75 4 9.6565 3.506
4 4 4 11.0825 3.756

UNF

Size, Number or Inches Basic Major Diameter (in) TPI Tensile Area, in2 Tensile Area Diameter, in Tap Drill No Tap Drill Size, in Clearance Drill (Close) Clearance Size (Close), in Clearance Drill (Free) Clearance Size (Free), in
0 0.060 80 0.0018 0.048 3/64 0.0469 52 0.0635 50 0.07
1 0.073 72 0.0028 0.059 53 0.0595 48 0.076 46 0.081
2 0.086 64 0.0039 0.071 50 0.07 43 0.089 41 0.096
3 0.099 56 0.0052 0.082 45 0.082 37 0.104 35 0.11
4 0.112 48 0.0066 0.092 42 0.0935 32 0.116 30 0.1285
5 0.125 44 0.0083 0.103 37 0.104 30 0.1285 29 0.136
6 0.138 40 0.0101 0.114 33 0.113 27 0.144 25 0.1495
8 0.164 36 0.0147 0.137 29 0.136 18 0.1695 16 0.177
10 0.19 32 0.0200 0.160 21 0.159 9 0.196 7 0.201
12 0.216 28 0.0258 0.181 14 0.182 2 0.221 1 0.228
1/4 0.25 28 0.0364 0.215 3 0.213 F 0.257 H 0.266
5/16 0.3125 24 0.0581 0.272 I 0.272 P 0.323 Q 0.332
3/8 0.375 24 0.0878 0.334 Q 0.332 W 0.386 X 0.397
7/16 0.4375 20 0.1187 0.389 25/64 0.3906 29/64 0.4531 15/32 0.4687
1/2 0.5 20 0.1600 0.451 29/64 0.4531 33/64 0.5156 17/32 0.5312
9/16 0.5625 18 0.2030 0.508 33/64 0.5156
5/8 0.625 18 0.2560 0.571 37/64 0.5781
3/4 0.75 16 0.3730 0.689 11/16 0.6875
7/8 0.875 14 0.5095 0.805 13/16 0.8125
1 1 12 0.6630 0.919 59/64 0.9219
1 1/8 1.125 12 0.8557 1.044 1 3/64 1.0469
1 1/4 1.25 12 1.0729 1.169 1 11/64 1.1719
1 5/16 1.3125 12 1.1908 1.231
1 3/8 1.375 12 1.3147 1.294 1 19/64 1.2969
1 1/2 1.5 12 1.5810 1.419 1 27/64 1.4219

References

[1]Machinery's Handbook, 28th Edition. Industrial Press.
[2]ANSI/AISC 360-16, Specification for Structural Steel Buildings.