UNIFIED SCREW THREADS
FINE SERIES, UNF, BASIC SIZES



 
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 1/8
1 1/4
1 3/8
1 1/2 
-28 UNF
-24 UNF
-24 UNF
-20 UNF
-20 UNF
-18 UNF
-18 UNF
-16 UNF
-14 UNF
-12 UNF
-12 UNF
-12 UNF
-12 UNF
-12 UNF
0.03571
0.04167
0.04167
0.05000
0.05000
0.05556
0.05556
0.06250
0.07143
0.08333
0.08333
0.08333
0.08333
0.08333 
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 
0.2268
0.2854
0.3479
0.4050
0.4675
0.5264
0.5889
0.7094
0.8286
0.9459
1.0709
1.1959
1.3209
1.4459 
0.2113
0.2674
0.3299
0.3834
0.4459
0.5024
0.5649
0.6823
0.7977
0.9098
1.0348
1.1598
1.2848
1.4098 
0.2062
0.2614
0.3239
0.3762
0.4387
0.4943
0.5568
0.6733
0.7874
0.8978
1.0228
1.1478
1.2728
1.3978 
Index