Specifications of International Thread Standards

UNC - Unified Coarse Thread. The old definition NC is comparable with the metric thread. The new term UNC is comparable with the ISO metric thread. NC and UNC threads are interchangeable, in an analogous manner like the metric and the ISO metric thread.
The flank angle is 60°.

Nominal
Diameter
Major
Diameter
Inch
Major
Diameter
mm
Tapping
Drill Size
mm
TPIPitch
mm
#1 - 64 UNC0.0731.8541.50640.397
#2 - 56 UNC0.0862.1841.78560.453
#3 - 48 UNC0.0992.5152.05480.529
#4 - 40 UNC0.1122.8452.27400.635
#5 - 40 UNC0.1253.1752.59400.635
#6 - 32 UNC0.1383.5052.77320.794
#8 - 32 UNC0.1644.1663.42320.794
#10 - 24 UNC0.1904.8263.82241.058
#12 - 24 UNC0.2165.4864.47241.058
1/4" - 20 UNC0.2506.3505.11201.270
5/16" - 18 UNC0.3137.9386.55181.411
3/8" - 16 UNC0.3759.5257.95161.587
7/16" - 14 UNC0.43811.1129.30141.814
1/2" - 13 UNC0.50012.70010.73131.954
9/16" - 12 UNC0.56314.28812.15122.117
5/8" - 11 UNC0.62515.87513.53112.309
3/4" - 10 UNC0.75019.05016.46102.540
7/8" - 9 UNC0.87522.22519.3492.822
1" - 8 UNC1.00025.40022.1583.175
1 1/8" - 7 UNC1.12528.57524.8773.628
1 1/4" - 7 UNC1.25031.75028.0573.628
1 3/8" - 6 UNC1.37534.92530.6064.233
1 1/2" - 6 UNC1.50038.10033.7064.233
1 3/4" - 5 UNC1.75044.45039.2655.080
2" - 4 1/2 UNC2.00050.80045.034.55.644
2 1/4" - 4 1/2 UNC2.25057.15051.384.55.644
2 1/2" - 4 UNC2.50063.50057.0046.350
2 3/4" - 4 UNC2.75069.85063.3646.350
3" - 4 UNC3.00076.20069.7146.350
3 1/4" - 4 UNC3.25082.55076.0646.350
3 1/2" - 4 UNC3.50088.90082.4146.350
3 3/4" - 4 UNC3.75095.25088.7646.350
4" - 4 UNC4.000101.60095.1146.350
UNC Thread