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12UNJ - 12 Pitch Unified Threads

with Controlled Root Radius and Increased Minor Diameter

The 12-thread series (12-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 5/8 inches.

5/8" - 1 5/8" 1 11/16 - 2 3/4" 2 7/8 - 4 1/4" 4 3/8" - 5 3/4" 5 5/8" - 6"

12UNJ Threads

Basic
Size
Primary		 Basic
Size
Secondary		 External thread - 12 UNJ Class 3A - Root Radius 0.0125 - 0.015 Internal thread - 12 UNJ Class 3B Root Radius 0.0125 - 0.015
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
5/8" - 12UNJ - 15.59 15.88 14.4 14.5 13.2 13.43 13.82 14.07 14.5 14.64 15.88
- 11/16" - 12 UNJ 17.17 17.46 15.98 16.09 14.79 15.02 15.4 15.66 16.09 16.22 17.46
3/4" - 12UNJ - 18.76 19.05 17.57 17.68 16.37 16.61 16.99 17.24 17.68 17.81 19.05
- 13/16" - 12 UNJ 20.35 20.64 19.16 19.26 17.96 18.19 18.58 18.83 19.26 19.4 20.64
7/8" - 12UNJ - 21.94 22.23 20.75 20.85 19.55 19.78 20.17 20.42 20.85 20.99 22.23
- 15/16" - 12 UNJ 23.52 23.81 22.33 22.44 21.13 21.37 21.75 22.01 22.44 22.58 23.81
- 1 1/16" - 12 UNJ 26.7 26.99 25.51 25.61 24.31 24.54 24.93 25.18 25.61 25.75 26.99
- 1 3/8" - 12 UNJ 29.87 30.16 28.68 28.79 27.48 27.72 28.1 28.36 28.79 28.93 30.16
- 1 5/16" - 12 UNJ 33.05 33.34 31.85 31.96 30.66 30.89 31.28 31.53 31.96 32.11 33.34
- 1 7/16" - 12 UNJ 36.22 36.51 35.03 35.14 33.83 34.07 34.45 34.71 35.14 35.28 36.51
 - 1 9/16" - 12 UNJ 39.4 39.69 38.2 38.31 37 37.24 37.63 37.88 38.31 38.46 39.69
1 5/8" - 12UNJ - 40.99 41.28 39.79 39.9 38.59 38.83 39.22 39.47 39.9 40.05 41.28
- 1 11/16" - 12 UNJ 42.57 42.86 41.37 41.49 40.18 40.42 40.8 41.06 41.49 41.64 42.86
1 3/4" - 12UNJ - 44.16 44.45 42.96 43.08 41.76 42.01 42.39 42.64 43.08 43.22 44.45
- 1 13/16" - 12 UNJ 45.75 46.04 44.55 44.66 43.35 43.59 43.98 44.23 44.66 44.81 46.04
1 7/8" - 12UNJ - 47.34 47.63 46.14 46.25 44.94 45.18 45.57 45.82 46.25 46.4 47.63
2" - 12UNJ - 48.92 49.21 47.72 47.84 46.53 46.77 47.15 47.41 47.84 47.99 49.21
- 1 15/16" - 12 UNJ 50.51 50.8 49.31 49.43 48.11 48.36 48.74 48.99 49.43 49.58 50.8
- 2 1/8" - 12 UNJ 53.69 53.98 52.49 52.6 51.29 51.53 51.92 52.17 52.6 52.75 53.98
2 1/4" - 12UNJ - 56.86 57.15 55.66 55.78 54.46 54.71 55.09 55.34 55.78 55.93 57.15
- 2 3/8" - 12 UNJ 60.04 60.33 58.83 58.95 57.64 57.88 58.27 58.52 58.95 59.1 60.33
2 1/2" - 12UNJ - 63.21 63.5 62.01 62.13 60.81 61.06 61.44 61.69 62.13 62.28 63.5
 - 2 5/8" - 12 UNJ 66.39 66.68 65.18 65.3 63.99 64.23 64.62 64.87 65.3 65.45 66.68
2 3/4" - 12UNJ - 69.56 69.85 68.36 68.48 67.16 67.41 67.79 68.04 68.48 68.63 69.85
- 2 7/8" - 12 UNJ 72.74 73.03 71.53 71.65 70.33 70.58 70.97 71.22 71.65 71.81 73.03
3" - 12UNJ - 75.91 76.2 74.71 74.83 73.51 73.76 74.14 74.39 74.83 74.98 76.2
- 3 1/8" - 12 UNJ 79.09 79.38 77.88 78 76.68 76.93 77.32 77.57 78 78.16 79.38
3 1/4" - 12UNJ - 82.26 82.55 81.06 81.18 79.86 80.11 80.49 80.74 81.18 81.33 82.55
- 3 3/8" - 12 UNJ 85.44 85.73 84.23 84.35 83.03 83.28 83.67 83.92 84.35 84.51 85.73
3 1/2" - 12UNJ - 88.61 88.9 87.4 87.53 86.21 86.46 86.84 87.09 87.53 87.69 88.9
- 3 5/8" - 12 UNJ 91.79 92.08 90.58 90.7 89.38 89.63 90.02 90.27 90.7 90.86 92.08
3 3/4" - 12UNJ - 94.96 95.25 93.75 93.88 92.56 92.81 93.19 93.44 93.88 94.04 95.25
- 3 7/8" - 12 UNJ 98.14 98.43 96.93 97.05 95.73 95.98 96.37 96.62 97.05 97.21 98.43
4" - 12UNJ - 101.31 101.6 100.1 100.23 98.9 99.16 99.54 99.79 99.72 100.39 101.6
 - 4 1/4" - 12 UNJ 104.49 104.78 103.28 103.4 102.08 102.33 102.72 102.97 103.4 103.56 104.78
4 1/4" - 12UNJ - 107.66 107.95 106.45 106.58 105.25 105.51 105.89 106.14 106.58 106.74 107.95
- 4 3/8" - 12 UNJ 110.84 111.13 109.63 109.75 108.43 108.68 109.07 109.32 109.75 109.91 111.13
4 1/2" - 12UNJ - 114.01 114.3 112.8 112.93 111.6 111.86 112.24 112.49 112.93 113.09 114.3
- 4 5/8" - 12 UNJ 117.19 117.48 115.97 116.1 114.78 115.03 115.42 115.67 116.1 116.27 117.48
4 3/4" - 12UNJ - 120.36 120.65 119.15 119.28 117.95 118.21 118.59 118.84 119.28 119.44 120.65
- 4 7/8" - 12 UNJ 123.54 123.83 122.32 122.45 121.13 121.38 121.77 122.02 122.45 122.62 123.83
5" - 12UNJ - 126.71 127 125.5 125.63 124.3 124.56 124.94 125.19 125.63 125.79 127
- 5 1/4" - 12 UNJ 129.89 130.18 128.67 128.8 127.48 127.73 128.12 128.37 128.8 128.97 130.18
5 1/4" - 12UNJ - 133.06 133.35 131.85 131.98 130.65 130.91 131.29 131.54 131.98 132.14 133.35
- 5 3/8" - 12 UNJ 136.24 136.53 135.02 135.15 133.83 134.08 134.47 134.72 135.15 135.32 136.53
5 1/2" - 12UNJ - 139.41 139.7 138.2 138.33 137 137.26 137.64 137.89 138.33 138.49 139.7
- 5 5/8" - 12 UNJ 142.59 142.88 141.37 141.5 140.17 140.43 140.82 141.07 141.5 141.67 142.88
5 3/4" - 12UNJ - 145.76 146.05 144.54 144.68 143.35 143.61 143.99 144.24 144.68 144.85 146.05
- 5 7/8" - 12 UNJ 148.94 149.23 147.72 147.85 146.52 146.78 147.17 147.42 147.85 148.02 149.23
6" - 12UNJ - 152.11 152.4 150.89 151.03 149.7 149.96 150.34 150.59 151.03 151.2 152.4