UNIFIED SCREW THREADS
COARSE SERIES, UNC



 
Designation Pitch In. Major
Diameter In.
Effective
Diameter In.
Minor Diameter In.
Nut Bolt
1/4
5/16
3/8
7/16
1/2
9/16
5/8
3/4
7/8
1
1-1/8
1-1/4
1-3/8
1-1/2
1-3/4
2
2-1/4
2-1/2
2-3/4
3
3-1/4
3-1/2
3-3/4
20 UNC
18 UNC
16 UNC
14 UNC
13 UNC
12 UNC
11 UNC
10 UNC
9 UNC
8 UNC
7 UNC
7 UNC
6 UNC
6 UNC
5 UNC
4½ UNC
4½ UNC
4 UNC
4 UNC
4 UNC
4 UNC
4 UNC
4 UNC
4 UNC 
0.05000
0.05556
0.06250
0.07143
0.07692
0.08333
0.09091
0.10000
0.11111
0.12500
0.14286
0.14286
0.16667
0.16667
0.20000
0.22220
0.22220
0.50000
0.50000
0.50000
0.50000
0.25000
0.25000
0.25000 
0.2500
0.3125
0.3750
0.4375
0.5000
0.5625
0.6250
0.7500
0.8750
1.0000
1.1250
1.2500
1.3750
1.5000
1.7500
2.0000
2.2500
2.5000
2.7500
3.0000
3.2500
3.5000
3.7500
4.000
0.2175
0.2764
0.3344
0.3911
0.4500
0.5084
0.5660
0.6850
0.8028
0.9188
1.0322
1.1572
1.2667
1.3917
1.6201
1.8557
2.1057
2.3376
2.5876
2.8376
3.0876
3.3376
3.5876
3.8376 
0.1959
0.2524
0.9073
0.3602
0.4167
0.4723
0.5266
0.6417
0.7547
0.8647
0.9704
1.0954
1.1946
1.3196
1.5335
1.7594
2.0094
2.2294
2.4794
2.7294
2.9794
3.2294
3.4794
3.7294 
0.1887
0.2443
0.2983
0.3499
0.4056
0.4603
0.5135
0.6273
0.7387
0.8466
0.9497
1.0747
1.1705
1.2955
1.5046
1.7274
1.9774
2.1933
2.4433
2.6933
2.9433
3.1933
3.4433
3.6933