820 Thompson Ave. Unit 41, Glendale, CA 91201

Phone: 1-800-896-3459 Fax: 1-866-707-9864
info@precion-inc.net

Basic Dimensions for Unified Screw Threads, UNC (Coarse Thread), UNF (Fine Thread), UNEF (Extra Fine Thread)

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

Precion, Inc. 820 Thompson Ave. Unit 41, Glendale, CA 91201　　　©2009 Precion, Inc. All Rights Reserved.
Please notify us of any errors on the sheet.
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Coarse-Thread Series, UNC
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Fine-Thread Series, UNF
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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
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Basic Major Diameter
Threads per Inch
Basic Pitch Diameter
Minor Diameter
Sizes
External Thread
Internal Thread
-
External Thread
Internal Thread
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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
-
-
-
-
-
-
-
-
-
-
-
-
*** All dimensions are given in inches.