UNF

UNF - Unified National Fine Thread

UNF threads ANSI B1.1
Nominal Diameter
(in)
Threads per inchMajor Diameter
(in)
Major Diameter
(mm)
Tapping Drill Size
(mm)
Pitch
(mm)
0800.061.5241.250.317
1720.0731.8541.550.353
2640.0682.1841.90.397
3560.0992.5152.150.453
4480.1122.8452.40.529
5440.1253.1752.70.577
6400.1383.5052.950.635
8360.1644.1663.50.705
10320.194.8264.10.794
12280.2165.4864.70.907
1/4"280.256.355.50.907
5/16"240.3137.9386.91.058
3/8"240.3759.5258.51.058
7/16"200.43811.1129.91.27
1/2"200.512.711.51.27
9/16"180.56314.28812.91.411
5/8"180.62515.87514.51.411
3/4"160.7519.0517.51.587
7/8"140.87522.22520.41.814
1"12125.423.252.117
1 1/8"121.12528.57526.52.117
1 1/4"121.2531.7529.52.117
1 3/8"121.37543.92532.752.117
1 1/2"121.538.1362.117