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UNC (Coarse Thread), UNF (Fine Thread), UNEF (Extra Fine Thread) Unified Screw - Dimension chart

*** All dimensions are given in inches.

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Coarse-Thread Series, UNC
-
Fine-Thread Series, UNF
-
Extra-Fine-Thread Series, UNEF
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Basic Major Diameter
Threads per Inch
Basic Pitch Diameter
Minor Diameter
-
Basic Major Diameter
Threads per Inch
Basic Pitch Diameter
Minor Diameter
-
Basic Major Diameter
Threads per Inch
Basic Pitch Diameter
Minor Diameter
Sizes
External Thread
Internal Thread
-
External Thread
Internal Thread
-
External Thread
Internal Thread
#0
-
-
-
-
-
-
0.0600
80
0.0519
0.0447
0.0465
-
-
-
-
-
-
#1
0.0730
64
0.0629
0.0538
0.0561
-
0.0730
72
0.064
0.056
0.058
-
-
-
-
-
-
#2
0.0860
56
0.0744
0.0641
0.0667
-
0.0860
64
0.0759
0.0668
0.0691
-
-
-
-
-
-
#3
0.0990
48
0.0855
0.0734
0.0764
-
0.0990
56
0.0874
0.0771
0.0797
-
-
-
-
-
-
#4
0.1120
40
0.0958
0.0813
0.0849
-
0.1120
48
0.0985
0.0864
0.0894
-
-
-
-
-
-
#5
0.1250
40
0.1088
0.0943
0.0979
-
0.1250
44
0.1102
0.0971
0.1004
-
-
-
-
-
-
#6
0.1380
32
0.1177
0.0997
0.1042
-
0.1380
40
0.1218
0.1073
0.1109
-
-
-
-
-
-
#8
0.1640
32
0.1437
0.1257
0.1302
-
0.1640
36
0.146
0.1299
0.1339
-
-
-
-
-
-
#10
0.1900
24
0.1629
0.1389
0.1449
-
0.1900
32
0.1697
0.1517
0.1562
-
-
-
-
-
-
#12
0.2160
24
0.1889
0.1649
0.1709
-
0.2160
28
0.1928
0.1722
0.1773
-
0.2160
32
0.1957
0.1777
0.1822
1/4
0.2500
20
0.2175
0.1887
0.1959
-
0.2500
28
0.2268
0.2062
0.2113
-
0.2500
32
0.2297
0.2117
0.2162
5/16
0.3125
18
0.2764
0.2443
0.2524
-
0.3125
24
0.2854
0.2614
0.2674
-
0.3125
32
0.2922
0.2742
0.2787
3/8
0.3750
16
0.3344
0.2983
0.3073
-
0.3750
24
0.3479
0.3239
0.3299
-
0.3750
32
0.3547
0.3367
0.3412
7/16
0.4375
14
0.3911
0.3499
0.3602
-
0.4375
20
0.405
0.3762
0.3834
-
0.4375
28
0.4143
0.3937
0.3988
1/2
0.5000
13
0.4500
0.4056
0.4167
-
0.5000
20
0.4675
0.4387
0.4459
-
0.5000
28
0.4768
0.4562
0.4613
9/16
0.5625
12
0.5084
0.4603
0.4723
-
0.5625
18
0.5264
0.4943
0.5024
-
0.5625
24
0.5354
0.5114
0.5174
5/8
0.6250
11
0.5660
0.5135
0.5266
-
0.6250
18
0.5889
0.5568
0.5649
-
0.6250
24
0.5979
0.5739
0.5799
3/4
0.7500
10
0.6850
0.6273
0.6417
-
0.7500
16
0.7094
0.6733
0.6823
-
0.7500
20
0.7175
0.6887
0.6959
7/8
0.8750
9
0.8028
0.7387
0.7547
-
0.8750
14
0.8286
0.7874
0.7977
-
0.8750
20
0.8425
0.8137
0.8209
1
1.0000
8
0.9188
0.8466
0.8647
-
1.0000
12
0.9459
0.8978
0.9098
-
1.0000
20
0.9675
0.9387
0.9459
1 8/1
1.1250
7
1.0322
0.9497
0.9704
-
1.1250
12
1.0709
1.0228
1.0348
-
1.1250
18
1.0889
1.0568
1.0649
1 1/4
1.2500
7
1.1572
1.0747
1.0954
-
1.2500
12
1.1959
1.1478
1.1598
-
1.2500
18
1.2139
1.1818
1.1899
1 3/8
1.3750
6
1.2667
1.1705
1.1946
-
1.3750
12
1.3209
1.2728
1.2848
-
1.3750
18
1.3389
1.3068
1.3149
1 1/2
1.5000
6
1.3917
1.2955
1.3196
-
1.5000
12
1.4459
1.3978
1.4098
-
1.5000
18
1.4639
1.4318
1.4399
1 3/4
1.7500
5
1.6201
1.5046
1.5335
-
-
-
-
-
-
-
1.7500
18
1.5889
1.5568
1.5649
2
2.0000
4.5
1.8557
1.7274
1.7594
-
-
-
-
-
-
-
-
-
-
-
-
2 1/4
2.2500
4.5
2.1057
1.9774
2.0094
-
-
-
-
-
-
-
-
-
-
-
-
2 1/2
2.5000
4
2.3376
2.1933
2.2294
-
-
-
-
-
-
-
-
-
-
-
-

 

***** The above data sheet can be used for information purpose only. No responsibility can be accepted for errors or omissions by whatever cause.

 

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