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Metric threadsMetric threads.

Diameter (M) Coarse thread Fine thread
Pitch (P) Diameter (D1) Pitch (P) Diameter (D1) Pitch (P) Diameter (D1) Pitch (P) Diameter (D1)
1 0.25 0.729 0.2 0.783        
1.1 0.25 0.829 0.2 0.883        
1.2 0.25 0.929 0.2 0.983        
1.4 0.3 1.075 0.2 1.183        
1.6 0.35 1.221 0.2 1.383        
1.8 0.35 1.421 0.2 1.583        
2 0.4 1.567 0.25 1.729        
2.2 0.4 1.713 0.25 1.929        
2.5 0.45 2.013 0.35 2.121        
3 0.5 2.459 0.35 2.621        
3.5 0.6 2.850 0.35 3.121        
4 0.7 3.242 0.5 3.459        
4.5 0.75 3.688 0.5 3.959        
5 0.8 4.134 0.5 4.459        
5.5     0.5 1.959        
6 1 4.917 0.75 5.188        
7 1 5.917 0.75 6.188        
8 1.25 6.647 1 6.917        
9 1.25 7.647 1 7.919        
10 1.5 8.376 1.25 8.647 1 8.917    
11 1.5 9.376 1 9.917        
12 1.75 10.106 1.5 10.376 1.25 10.647 1 10.917
14 2 11.835 1.5 12.376        
15   13.376 1.5 13.376        
16 2 13.835 1.5 14.376        
17     1.5 15.376        
18 2.5 15.294 2 15.835 1.5 16.376    
20 2.5 17.294 2 17.835 1.5 18.376    
22 2.5 19.294 2 19.835 1.5 20.376    
24 3 20.752 2 21.835 1.5 22.376    
25     2 22.835 1.5 23.376    
26     1.5 24.376        
27 3 23.752 2 24.835 1.5 25.376    
28     2 25.835 1.5 26.376    
30 3.5 26.211 2 27.835 1.5 28.376    
32     2 29.835 1.5 30.376    
33 3.5 29.211 2 30.835 1.5 31.376    
35     1.5 33.376        
36 4 31.670 3 32.752 1.5 34.376    
38     1.5 36.376        
39 4 34.670 3 35.752 1.5 37.376    
40     3 36.752 1.5 38.376    
42 4.5 37.129 3 38.752 1.5 40.376    
45 4.5 40.129 3 41.752 1.5 43.376    
48 5 42.587 3 44.752 1.5 46.376    
50     3 46.752 1.5 48.376    
52 5 46.587 3 48.752 1.5 50.376    
55     4 50.670 2 52.835    
56 5.5 50.046 4 51.670 2 53.835    
58     4 53.670 2 55.835    
60 5.5 54.046 4 55.670 2 57.835    
62     4 57.670 2 59.835    
64 6 57.505 4 59.670 2 61.835    
65     4 60.670        
68 6 61.505 4 63.670        
70 6 63.505 4 65.670        
72 6 65.505 4 67.670        
75     4 70.670        
76 6 69.505 4 71.670        
78     2 75.835        
80 6 73.505 4 75.670        
82     2 79.835        
85 6 78.505 4 80.670        
90 6 83.505 4 85.670        
95 6 88.505 4 90.670        
100 6 93.505 4 95.670        
105 6 98.505 4 100.670        
110 6 103.505 4 105.670      

Unified threadsUnified threads.

Size Major diameter (D) Pitches
Coarse (UNC) Fine (UNF) Extra fine (UNEF)
Threads per inch Pitch (P) Minor diameter (D1) Threads per inch Pitch (P) Minor diameter (D1) Threads per inch Pitch (P) Minor diameter (D1)
No. 0 1.524       80 0.318 1.181      
No. 1 1.854 64 0.397 1.425 72 0.353 1.473      
No. 2 2.184 56 0.454 1.720 64 0.397 1.755      
No. 3 2.515 48 0.529 1.941 56 0.454 2.024      
No. 4 2.845 40 0.635 2.156 48 0.529 2.271      
No. 5 3.175 40 0.635 2.487 44 0.577 2.550      
No. 6 3.505 32 0.794 2.647 40 0.635 2.817      
No. 8 4.166 32 0.794 3.307 36 0.706 3.401      
No. 10 4.826 24 1.058 3.680 32 0.794 3.965      
No. 12 5.486 24 1.058 4.341 28 0.907 4.503 32 0.794 4.628
1/4 6.350 20 1.270 4.976 28 0.907 5.367 32 0.794 5.491
5/16 7.938 18 1.411 6.411 24 1.058 6.792 32 0.794 7.079
3/8 9.525 16 1.588 7.805 24 1.058 8.379 32 0.794 8.666
7/16 11.113 14 1.814 9.149 20 1.270 9.738 28 0.907 10.254
1/2 12.700 13 1.954 10.584 20 1.270 11.326 28 0.907 11.841
9/16 14.288 12 2.117 11.996 18 1.411 12.761 24 1.058 13.142
5/8 15.875 11 2.309 13.376 18 1.411 14.348 24 1.058 14.729
11/16 17.463             24 1.058 16.317
3/4 19.050 10 2.540 16.299 16 1.588 17.330 20 1.270 17.676
13/16 20.638             20 1.270 19.263
7/8 22.225 9 2.822 19.169 14 1.814 20.262 20 1.270 20.851
15/16 23.813             20 1.270 22.438
1 25.400 8 3.175 21.963 12 2.117 23.109 20 1.270 24.026
1 1/16 26.988             18 1.411 25.461
1 1/8 28.575 7 3.629 24.648 12 2.117 26.284 18 1.411 27.048
1 3/16 47.625             18 1.411 28.636
1 1/4 31.750 7 3.629 27.823 12 2.117 29.459 18 1.411 30.223
1 5/16 33.338             18 1.411 31.811
1 3/8 34.925 6 4.233 30.343 12 2.117 32.634 18 1.411 33.398
1 7/16 36.513             18 1.411 34.986
1 1/2 38.100 6 4.233 33.518 12 2.117 35.809 18 1.411 36.573
1 9/16 39.688             18 1.411 38.160
1 5/8 41.275             18 1.411 39.748
1 11/16 42.863             18 1.411 41.335
1 3/4 44.450 5 5.080 38.951            
2 50.800 4 1/2 5.644 44.689            
2 1/4 57.150 4 1/2 5.644 51.039            
2 1/2 63.500 4 6.350 56.627            
2 3/4 69.850 4 6.350 62.977            
3 76.200 4 6.350 69.327            
3 1/4 82.550 4 6.350 75.677            
3 1/2 88.900 4 6.350 82.027            
3 3/4 95.250 4 6.350 85.202            
4 101.600 4 6.350 94.727          

Whitworth threadsWhitworth threads.

Size Major diameter (D) Pitches
Coarse (BSW) Fine (BSF)
Threads per inch Pitch (P) Minor diameter (D1) Threads per inch Pitch (P) Minor diameter (D1)
1/8 3.175 40 0.635 2.362      
5/32 3.969 32 0.794 2.953      
3/16 4.763 24 1.058 3.406      
1/4 6.350 20 1.270 4.724 26 0.977 5.072
9/32 7.144       26 0.977 5.862
5/16 7.938 18 1.411 6.131 22 1.155 6.429
3/8 9.525 16 1.588 7.492 20 1.270 7.866
7/16 11.113 14 1.814 8.789 18 1.411 9.268
1/2 12.700 12 2.117 9.990 16 1.588 10.630
9/16 14.288 12 2.117 11.578 16 1.588 12.217
5/8 15.875 11 2.309 12.918 14 1.814 13.513
11/16 17.463 11 2.309 14.507 14 1.814 15.098
3/4 19.050 10 2.540 15.798 12 2.117 16.292
7/8 22.225 9 2.822 18.611 11 2.309 19.268
1 25.400 8 3.175 21.335 10 2.540 22.149
1 1/8 28.575 7 3.629 23.929      
1 1/4 31.750 7 3.629 27.104      
1 1/2 38.100 6 4.233 32.680      
1 5/8 41.275 5 5.080 34.769      
1 3/4 44.450 5 5.080 37.944      
1 7/8 47.625 4 1/2 5.644 40.397      
2 50.800 4 1/2 5.644 43.572      
2 1/4 57.150 4 6.350 49.018      
2 1/2 63.500 4 6.350 55.368      
2 3/4 69.850 3 1/2 7.257 60.556      
3 76.200 3 1/2 7.257 66.906      
3 1/4 82.550 3 1/4 7.815 72.542      
3 1/2 88.900 3 1/4 7.815 78.892      
3 3/4 95.250 3 8.467 84.406      
4 101.600 3 8.467 90.756      
4 1/2 114.300 2 7/8 8.835 102.986      
5 127.000 2 3/4 9.236 115.172      
5 1/2 139.700 2 5/8 9.676 127.308      
6 152.400 2 1/2 10.160 139.388    

Parallel pipe threadsParallel pipe threads.

Thread Major diameter (D) Threads per inch Pitch (P) Minor diameter (D1)
G 1/16 A 7.723 28 0.907 6.561
G 1/8 A 9.728 28 0.907 8.566
G 1/4 A 13.157 19 1.337 11.455
G 3/8 A 16.662 19 1.337 14.950
G 1/2 A 20.955 14 1.814 18.631
G 5/8 A 22.911 14 1.814 20.581
G 3/4 A 26.411 14 1.814 24.117
G 7/8 A 30.201 14 1.814 27.877
G 1 A 33.249 11 2.309 30.291
G 1 1/8 A 37.897 11 2.309 34.939
G 1 1/4 A 41.910 11 2.309 38.952
G 1 1/2 A 47.803 11 2.309 44.845
G 1 3/4 A 53.746 11 2.309 50.788
G 2 A 59.614 11 2.309 56.656
G 2 1/4 A 65.710 11 2.309 62.752
G 2 1/2 A 75.184 11 2.309 72.226
G 2 3/4 A 81.534 11 2.309 78.576
G 3 A 87.884 11 2.309 84.926
G 3 1/2 A 100.330 11 2.309 97.372
G 4 A 113.030 11 2.309 110.072
G 4 1/2 A 125.730 11 2.309 122.772
G 5 A 138.430 11 2.309 135.472
G 5 1/2 151.130 11 2.309 148.172
G 6 A 163.830 11 2.309 160.872

Tapered pipe threadsTapered pipe threads.

Thread Major diameter (D) Threads per inch Pitch (P) Minor diameter (D1)
R 1/16 7.723 28 0.907 6.561
R 1/8 9.728 28 0.907 8.566
R 1/4 13.157 19 1.337 11.445
R 3/8 16.662 19 1.337 14.950
1/2 20.955 14 1.814 18.631
R 3/4 26.441 14 1.814 24.117
R 1 33.249 11 2.309 30.291
R 1 1/4 41.910 11 2.309 38.952
R 1 1/2 47.803 11 2.309 44.845
R 2 59.614 11 2.309 56.656
R 2 1/2 75.184 11 2.309 72.226
R 3 87.884 11 2.309 84.926
R 3 1/2 100.330 11 2.309 97.372
R 4 113.030 11 2.309 110.072
R 5 138.430 11 2.309 135.472
R 6 163.830 11 2.309 160.872

Trapezoidal threadsTrapezoidal threads.

Major diameter (Tr) Pitch (P) Minor diameter (D1) Pitch (P) Minor diameter (D1) Pitch (P) Minor diameter (D1)
8 1.5 6.5        
9 1.5 7.5 2 7.0    
10 1.5 8.5 2 8.0    
11 2 9.0 3 8.0    
12 2 10.0 3 9.0    
14 2 12.0 3 11.0    
16 2 14.0 4 12.0    
18 2 16.0 4 14.0    
20 2 18.0 4 16.0    
22 3 19.0 5 17.0 8 14.0
24 3 21.0 5 19.0 8 16.0
26 3 23.0 5 21.0 8 18.0
28 3 25.0 5 23.0 8 20.0
30 3 27.0 6 24.0 10 20.0
32 3 29.0 6 26.0 10 22.0
34 3 31.0 6 28.0 10 24.0
36 3 33.0 6 30.0 10 26.0
38 3 35.0 7 31.0 10 28.0
40 3 37.0 7 33.0 10 30.0
42 3 39.0 7 35.0 10 32.0
44 3 41.0 7 37.0    
50 8 41.0        
60 9 50.0      

Tapping screw threadsTapping screw threads.

Nominal diameter (ST) Pitch (P) Taper length (y) Miner diameter (D1)
Form C Form F
2.2 0.8 2.0 1.6 1.52 - 1.63
2.6 0.9 2.3 1.8 1.80 - 1.90
2.9 1.1 2.6 2.1 2.08 - 2.18
3.2 1.3 3.0 2.5 2.29 - 2.39
3.5 1.3 3.2 2.5 2.51 - 2.64
3.9 1.3 3.5 2.7 2.77 - 2.92
4.2 1.4 3.7 2.8 2.95 - 3.10
4.8 1.6 4.3 3.2 3.43 - 3.58
5.5 1.8 5.0 3.6 3.99 - 4.17
6.3 1.8 6.0 3.6 4.70 - 4.88


Wood screw threadsWood screw threads.

Nominal diameter (ST) Pitch (P) Minor diameter (D1)
1.6 0.7 1.1
2 0.9 1.4
2.5 1.1 1.7
3 1.4 2.1
3.5 1.6 2.4
4 1.8 2.8
4.5 2.0 3.1
5 2.2 3.5
5.5 2.4 3.8
6 2.6 4.2
7 3.2 4.9
8 3.6 5.6
10 4.5 7
12 5.0 9
16 6.0 12
20 7.0 15

Threads for plastic materials

 

Kind of plastic material Nominal diameter (D) Pitch (P) Minor diameter (D1)
Flat and thin Threads for plastic materials. Flat and thin. 2.5 1.13 1.61
3 1.35 1.91
3.5 1.58 2.21
4 1.79 2.51
4.5 2.01 2.71
5 2.25 3.11
6 2.70 3.72
Thermo hardened Threads for plastic materials. Thermo hardened. 2.2 0.82 1.50 - 1.55
2.9 1.35 1.86 - 1.96
3.5 1.60 2.10 - 2.20
3.9 1.80 2.44 - 2.54
4.2 2.00 2.60 - 2.70
4.8 2.20 2.90 - 3.00
6.3 2.60 3.80 - 3.95
Thermo hardened
(double thread)		 Threads for plastic materials. Thermo hardened - double thread. 3 2.11 1.75 - 1.96
3.5 2.51 1.85 - 2.16
4 2.71 2.15 - 2.46
4.5 2.81 2.35 - 2.66
5 3.01 2.70 - 3.01
5.5 3.01 3.20 - 3.51
6 3.11 3.60 - 3.91
7 3.51 4.55 - 4.86
Soft Threads for plastic materials. Soft. 2.6 2.40 1.85
3.2 2.60 2.05
3.7 3.50 2.35
4.2 3.60 2.75
4.7 3.80 2.95
5.2 4.00 3.35
5.8 4.60 4.00
6.9 5.00 4.55

Threads of thread forming screwsThreads of thread forming screws.

Nominal diameter (D) Pitch (P) Minor diameter (D1)
2.5 0.45 1.85
3 0.50 2.30
3.5 0.60 2.65
4 0.70 3.00
5 0.80 4.65
6 1.00 3.72