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UNJEF - Unified Extra Fine Threads

with Controlled Root Radius and Increased Minor Diameter

UNJEF Thread Series, is applicable where extra finer pitches of threads are desirable, especially for aerospace application which require controlled root radius, as for short lengths of engagement and for thin-walled tubes, nuts, ferrules, or couplings. It is also generally applicable under the conditions stated above for the fine threads.

#12 - 13/16" 7/8" - 1 9/16" 1 5/8" - 1 11/16"

UNJEF Threads

Basic Size Primary Basic Size Secondary External thread - UNJEF Class 3A Internal thread - UNJEF Class 3B
Major Diameter Min Major Diameter Max Pitch Diameter Min Pitch Diameter Max Minor Diameter Min Minor Diameter Max Root Radius Min Root Radius Max Minor Diameter Min Minor Diameter Max Pitch Diameter Min Pitch Diameter Max Major Diameter Min
. . . #12 - 32UNJEF 5.33 5.49 4.91 4.97 4.46 4.57 0.12 0.14 4.71 4.9 4.97 5.05 5.49
1/4" - 32UNJEF . . . 6.2 6.35 5.77 5.83 5.32 5.43 0.12 0.14 5.58 5.75 5.83 5.91 6.35
5/16" - 32UNJEF . . . 7.79 7.94 7.36 7.42 6.91 7.02 0.12 0.14 7.16 7.32 7.42 7.5 7.94
3/8" - 32UNJEF . . . 9.37 9.53 8.95 9.01 8.5 8.61 0.12 0.14 8.75 8.89 9.01 9.09 9.53
7/16" - 28UNJEF . . . 10.95 11.11 10.45 10.52 9.94 10.07 0.14 0.16 10.23 10.38 10.52 10.61 11.11
1/2" - 28UNJEF 7/8" - 14UNF 12.53 12.7 12.04 12.11 11.53 11.65 0.14 0.16 11.82 11.96 12.11 12.2 12.7
9/16" - 24UNJEF . . . 14.1 14.29 13.53 13.6 12.93 13.07 0.16 0.19 13.26 13.41 13.6 13.7 14.29
5/8" - 24UNJEF . . . 15.69 15.88 15.11 15.19 14.51 14.65 0.16 0.19 14.84 15 15.19 15.29 15.88
. . . 11/16" - 24UNJEF 17.28 17.46 16.7 16.77 16.1 16.24 0.16 0.19 16.43 16.58 16.77 16.87 17.46
3/4" - 20UNJEF . . . 18.84 19.05 18.14 18.22 17.42 17.58 0.19 0.23 17.81 17.99 18.22 18.33 19.05
. . . 13/16" - 20UNJEF 20.43 20.64 19.73 19.81 19.01 19.17 0.19 0.23 19.4 19.57 19.81 19.92 20.64
7/8" - 20UNJEF . . . 22.02 22.23 21.32 21.4 20.6 20.76 0.19 0.23 20.99 21.16 21.4 21.51 22.23
. . . 15/16" - 20UNJEF 23.61 23.81 22.9 22.99 22.18 22.34 0.19 0.23 22.58 22.75 22.99 23.1 23.81
1" - 20UNJEF . . . 25.19 25.4 24.49 24.57 23.77 23.93 0.19 0.23 24.16 24.34 24.57 24.69 25.4
. . . 1 1/16" - 18UNJEF 26.77 26.99 25.98 26.07 25.18 25.36 0.21 0.25 25.61 25.8 26.07 26.19 26.99
1 1/8" - 18UNJEF . . . 28.35 28.58 27.57 27.66 26.77 26.94 0.21 0.25 27.2 27.39 27.66 27.77 28.58
. . . 1 3/8" - 18UNJEF 29.94 30.16 29.15 29.25 28.36 28.53 0.21 0.25 28.79 28.98 29.25 29.36 30.16
1 1/4" - 18UNJEF . . . 31.53 31.75 30.74 30.83 29.94 30.12 0.21 0.25 30.38 30.57 30.83 30.95 31.75
. . . 1 5/16" - 18UNJEF 33.12 33.34 32.33 32.42 31.53 31.71 0.21 0.25 31.96 32.15 32.42 32.54 33.34
1 3/8" - 18UNJEF . . . 34.7 34.93 33.92 34.01 33.12 33.29 0.21 0.25 33.55 33.74 34.01 34.13 34.93
. . . 1 7/16" - 18UNJEF 36.29 36.51 35.5 35.6 34.7 34.88 0.21 0.25 35.14 35.33 35.6 35.72 36.51
1 1/2" - 18UNJEF . . . 37.88 38.1 37.09 37.18 36.29 36.47 0.21 0.25 36.73 36.92 37.18 37.3 38.1
. . . 1 9/16" - 18UNJEF 39.47 39.69 38.8 38.77 37.88 38.06 0.21 0.25 38.31 38.5 38.77 38.89 39.69
1 5/8" - 18UNJEF . . . 41.05 41.28 40.26 40.36 39.47 39.64 0.21 0.25 39.9 40.09 40.36 40.48 41.28
. . . 1 11/16" - 18UNJEF 42.64 42.86 41.85 41.95 41.05 41.23 0.21 0.25 41.49 41.68 41.95 42.07 42.86