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UNJF - Unified Fine Threads

with Controlled Root Radius and Increased Minor Diameter

UNJF Thread Series, is suitable for the production of bolts, screws, and nuts for aerospace applications where the Root Radius is controlled. External threads of this series have greater tensile stress area than comparable sizes of the Coarse series. The Fine series is suitable when the resistance to stripping of both external

#0 - 5/16" 5/16" - 1 1/2"

UNJF - Unified Fine Threads

Basic Size Primary Basic Size Secondary External thread - UNJF Class 3A Internal thread - UNJF 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
#0 - 80 UNJF . . . 1.44 1.52 1.29 1.32 1.1 1.16 0.05 0.06 1.22 1.3 1.32 1.36 1.52
. . . #1 - 72 UNJF 1.77 1.85 1.59 1.63 1.39 1.45 0.05 0.06 1.51 1.6 1.63 1.67 1.85
#2 - 64 UNJF . . . 2.09 2.18 1.89 1.93 1.67 1.73 0.06 0.07 1.8 1.9 1.93 1.98 2.18
. . . #3 - 56 UNJF 2.41 2.51 2.18 2.22 1.92 1.99 0.07 0.08 2.07 2.19 2.22 2.27 2.51
#4 - 48 UNJF . . . 2.73 2.84 2.46 2.5 2.16 2.24 0.08 0.1 2.33 2.47 2.5 2.56 2.84
#5 - 44 UNJF 7/8" - 14 UNF 3.05 3.18 2.75 2.8 2.42 2.51 0.09 0.1 2.61 2.76 2.8 2.86 3.18
#6 - 40 UNJF . . . 3.38 3.51 3.04 3.09 2.68 2.77 0.1 0.11 2.89 3.05 3.09 3.16 3.51
#8 - 36 UNJF . . . 4.03 4.17 3.66 3.71 3.26 3.35 0.11 0.13 3.48 3.66 3.71 3.78 4.17
#10 - 32 UNJF . . . 4.67 4.83 4.25 4.31 3.8 3.91 0.12 0.14 4.05 4.25 4.31 4.38 4.83
. . . #12 - 28 UNJF 5.32 5.49 4.84 4.9 4.32 4.44 0.14 0.16 4.6 4.82 4.9 4.98 5.49
1/4" - 28 UNJF . . . 6.18 6.35 5.7 5.76 5.18 5.3 0.14 0.16 5.47 5.66 5.76 5.84 6.35
5/16" - 24 UNJF . . . 7.75 7.94 7.18 7.25 6.58 6.72 0.16 0.19 6.91 7.11 7.25 7.34 7.94
3/8" - 24 UNJF . . . 9.34 9.53 8.76 8.84 8.16 8.3 0.16 0.19 8.49 8.68 8.84 8.93 9.53
7/16" - 20 UNJF . . . 10.91 11.11 10.21 10.29 9.49 9.64 0.19 0.23 9.88 10.08 10.29 10.39 11.11
1/2" - 20 UNJF . . . 12.49 12.7 11.79 11.87 11.07 11.23 0.19 0.23 11.46 11.66 11.87 11.98 12.7
9/16" - 18 UNJF . . . 14.07 14.29 13.28 13.37 12.49 12.66 0.21 0.25 12.91 13.12 13.37 13.48 14.29
5/8" - 18 UNJF . . . 15.65 15.88 14.87 14.96 14.07 14.24 0.21 0.25 14.5 14.7 14.96 15.07 15.88
3/4" - 16 UNJF . . . 18.81 19.05 17.92 18.02 17.02 17.22 0.24 0.29 17.51 17.72 18.02 18.14 19.05
7/8" - 14 UNJF . . . 21.96 22.23 20.94 21.05 19.92 20.13 0.27 0.33 20.46 20.71 21.05 21.18 22.23
1" - 12 UNJF . . . 25.11 25.4 23.91 24.03 22.72 22.96 0.32 0.38 23.34 23.59 24.03 24.17 25.4
1 1/8" - 12 UNJF . . . 28.29 28.58 27.09 27.2 25.89 26.13 0.32 0.38 26.52 26.77 27.2 27.35 28.58
1 1/4" - 12 UNJF . . . 31.46 31.75 30.26 30.38 29.06 29.31 0.32 0.38 29.69 29.94 30.38 30.53 31.75
1 3/8" - 12 UNJF . . . 34.64 34.93 33.43 33.55 32.23 32.48 0.32 0.38 32.87 33.12 33.55 33.71 34.93
1 1/2" - 12 UNJF . . . 37.81 38.1 36.6 36.73 35.41 35.66 0.32 0.38 36.04 36.29 36.73 36.89 38.1