UNIFIED SCREW THREADS
EXTRA FINE SERIES (UNEF)



 
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
11/16*
3/4
13/16*
7/8
15/16*
1
1-1/16*
1-1/8
1-3/16*
1-1/4
1-5/16*
1-3/8
1-7/16*
1-1/2
1-9/16*
1-5/8
1-11/16*
-32UNEF -32UNEF -32UNEF -28UNEF -28UNEF -24UNEF -24UNEF -24UNEF -20UNEF -20UNEF -20UNEF -20UNEF -20UNEF -18UNEF -18UNEF -18UNEF -18UNEF -18UNEF -18UNEF -18UNEF -18UNEF -18UNEF -18UNEF -18UNEF
*Second choice
0.03125
0.03125
0.03125
0.035714
0.035714
0.041667
0.041667
0.041667
0.050
0.050
0.050
0.050
0.050
0.055556
0.055556
0.055556
0.055556
0.055556
0.055556
0.055556
0.055556
0.055556
0.055556
0.055556
0.2500
0.3125
0.3750
0.4375
0.5000
0.5625
0.6250
0.6875
0.7500
0.8125
0.8750
0.9375
1.0000
1.0625
1.1250
1.1875
1.2500
1.3125
1.3750
1.4375
1.5000
1.5625
1.6250
1.6875 
0.2297
0.2922
0.3547
0.4143
0.4768
0.5354
0.5979
0.6604
0.7175
0.7800
0.8425
0.9050
0.9675
1.0264
1.0889
1.1514
1.2139
1.2764
1.3389
1.4014
1.4639
1.5264
1.5889
1.6514 
0.2162
0.2787
0.3412
0.3988
0.4613
0.5174
0.5799
0.6424
0.6959
0.7584
0.8209
0.8834
0.9459
1.0024
1.0649
1.1274
1.1899
1.2524
1.3149
1.3774
1.4399
1.5024
1.5649
1.6274 
0.2117
0.2742
0.3367
0.3937
0.4562
0.5114
0.5739
0.6364
0.6887
0.7512
0.8137
0.8762
0.9387
0.9943
1.0568
1.1193
1.1818
1.2443
1.3068
1.3693
1.4318
1.4943
1.5568
1.6193