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8UNJ - 8 Pitch Unified Threads

with Controlled Root Radius and Increased Minor Diameter

The 8-thread series (8-UNJ) is a uniform pitch series for large diameters requiring threads of medium-fine pitch Aerospace Quality Threads with controlled Root Radius, it is now used as a continuation of the Fine-Thread Series for diameters larger than 11⁄8 inches.

1 1/16" - 1 3/4" 1 13/16" - 3 1/8" 3 1/4" - 4

Basic Size Primary Basic Size Secondary External thread - 8UNJ Class 3A Root Radius 0.0188 - 0.0226 Internal thread - 8UNJ Class 3B Root Radius 0.0188 - 0.0226
Major Diameter Min Major Diameter Max Pitch Diameter Min Pitch Diameter Max Minor Diameter Min Minor Diameter Max Minor Diameter Min Minor Diameter Max Pitch Diameter Min Pitch Diameter Max Major Diameter Min
- 1 1/16" - 8UNJ 26.61 26.99 24.8 24.93 23 23.32 23.9 24.28 24.93 25.1 26.99
1 1/8" - 8UNJ - 28.19 28.58 26.38 26.51 24.58 24.91 25.48 25.86 26.51 26.68 28.58
- 1 3/8" - 8UNJ 29.78 30.16 27.97 28.1 26.17 26.5 27.07 27.45 28.1 28.27 30.16
1 1/4" - 8UNJ - 31.37 31.75 29.55 29.69 27.76 28.08 28.66 29.04 29.69 29.86 31.75
- 1 5/16" - 8UNJ 32.96 33.34 31.14 31.28 29.34 29.67 30.25 30.63 31.28 31.45 33.34
1 3/8" - 8UNJ 7/8" - 14 UNF 34.54 34.93 32.73 32.86 30.93 31.26 31.83 32.21 32.86 33.04 34.93
- 1 7/16" - 8UNJ 36.13 36.51 34.31 34.45 32.52 32.85 33.42 33.8 34.45 34.63 36.51
1 1/2" - 8UNJ - 37.72 38.1 35.9 36.04 34.1 34.43 35.01 35.39 36.04 36.22 38.1
- 1 9/16" - 8UNJ 39.31 39.69 37.49 37.63 35.69 36.02 36.6 36.98 37.63 37.81 39.69
1 5/8" - 8UNJ - 40.89 41.28 39.07 39.21 37.27 37.61 38.18 38.56 39.21 39.4 41.28
- 1 11/16" - 8UNJ 42.48 42.86 40.66 40.8 38.86 39.2 39.77 40.15 40.8 40.99 42.86
1 3/4" - 8UNJ - 44.07 44.45 42.24 42.39 40.45 40.78 41.36 41.74 42.39 42.58 44.45
- 1 13/16" - 8UNJ 45.66 46.04 43.83 43.98 42.03 42.37 42.95 43.33 43.98 44.16 46.04
1 7/8" - 8UNJ - 47.24 47.63 45.42 45.56 43.62 43.96 44.53 44.91 45.56 45.75 47.63
- 1 15/16" - 8UNJ 48.83 49.21 47 47.15 45.21 45.55 46.12 46.5 47.15 47.34 49.21
2" - 8UNJ - 50.42 50.8 48.59 48.74 46.79 47.13 47.71 48.09 48.74 48.93 50.8
- 2 1/8" - 8UNJ 53.59 53.98 51.76 51.91 49.97 50.31 50.88 51.26 51.91 52.11 53.98
2 1/4" - 8UNJ - 56.77 57.15 54.94 55.09 53.14 53.48 54.06 54.44 55.09 55.29 57.15
- 2 3/8" - 8UNJ 59.94 60.33 58.11 58.26 56.31 56.66 57.23 57.61 58.26 58.46 60.33
2 1/2" - 8UNJ - 63.12 63.5 61.28 61.44 59.49 59.83 60.41 60.79 61.44 61.64 63.5
- 2 5/8" - 8UNJ 66.29 66.68 64.46 64.61 62.66 63.01 63.58 63.96 64.61 64.82 66.68
2 3/4" - 8UNJ - 69.47 69.85 67.63 67.79 65.83 66.18 66.76 67.14 67.79 67.99 69.85
- 2 7/8" - 8UNJ 72.64 73.03 70.8 70.96 69.01 69.36 69.93 70.31 70.96 71.17 73.03
3" - 8UNJ - 75.82 76.2 73.97 74.14 72.18 72.53 73.11 73.49 74.14 74.35 76.2
- 3 1/8" - 8UNJ 78.99 79.38 77.15 77.31 75.35 75.71 76.28 76.66 77.31 77.53 79.38
3 1/4" - 8UNJ - 82.17 82.55 80.32 80.49 78.53 78.88 79.46 79.84 80.49 80.7 82.55
- 3 3/8" - 8UNJ 85.34 85.73 83.49 83.66 81.7 82.06 82.63 83.01 83.66 83.88 85.73
3 1/2" - 8UNJ - 88.52 88.9 86.67 86.84 84.87 85.23 85.81 86.19 86.84 87.06 88.9
- 3 5/8" - 8UNJ 91.69 92.08 89.84 90.01 88.05 88.41 88.98 89.36 90.01 90.23 92.08
3 3/4" - 8UNJ - 94.87 95.25 93.02 93.19 91.22 91.58 92.16 92.54 93.19 93.41 95.25
- 3 7/8" - 8UNJ 98.04 98.43 96.19 96.36 94.39 94.76 95.33 95.71 96.36 96.59 98.43
4" - 8UNJ - 101.22 101.6 99.36 99.54 97.57 97.93 98.51 98.89 99.54 99.76 101.6