Specification Library

Stud & Bolt Thread Pitches

Bolt
Diameter in
Inches
Stud UN
Thread Per
Inch
Bolts UNC
Threads
Per Inch
Bolts UNF
Threads
Per Inch
Wrench
Size
Inches
1/4 20 20 28
5/16 18 18 24
3/8 16 16 24
7/16 14 14 20
1/2 13 13 20 7/8
9/16 12 12 18
5/8 11 11 18 1-1/6
3/4 10 10 16 1-1/4
7/8 9 9 14 1-7/16
1 8 8 12 1-5/8
1-1/8 8 7 12 1-13/16
1-1/4 8 7 12 2
1-3/8 8 6 12 2-3/16
1-1/2 8 6 12 2-3/8
1-5/8 8 2-9/16
1-3/4 8 5 2-3/4
1-7/8 8 2-15/16
2 8 4-1/2 3-1/8
2-1/4 8 4-1/2 3-1/2
2-1/2 8 4 3-7/8
2-3/4 8 4 4-1/4
3 8 4 4-5/8
3-1/4 8 4
3-1/2 8 4
3-3/4 8 4
4 8 4