
Threads
Metric threads

Thread Diameter | Pitch | Core hole nut | Outer-Bolt-Ø | Bolt-Flanks-Ø | Bolt-Core-Ø | ||
---|---|---|---|---|---|---|---|
M | mm | mm | max. | min. | max. | min. | max. |
3 | 0,5 | 2,5 | 2,980 | 2,874 | 2,655 | 2,580 | 2,367 |
3,5 | 0,6 | 2,9 | 3,479 | 3,354 | 3,089 | 3,004 | 2,743 |
4 | 0,7 | 3,3 | 3,978 | 3,838 | 3,523 | 3,433 | 3,119 |
4,5 | 0,75 | 3,7 | 4,478 | 4,338 | 3,991 | 3,901 | 3,558 |
5 | 0,8 | 4,2 | 4,976 | 4,826 | 4,456 | 4,361 | 3,995 |
6 | 1 | 5 | 5,974 | 5,794 | 5,234 | 5,212 | 4,747 |
7 | 1 | 6 | 6,972 | 6,794 | 6,324 | 6,212 | 5,747 |
8 | 1,25 | 6,8 | 7,972 | 7,760 | 7,160 | 7,042 | 6,438 |
9 | 1,25 | 7,8 | 8,972 | 8,760 | 8,160 | 8,042 | 7,438 |
10 | 1,5 | 8,5 | 9,968 | 9,732 | 8,994 | 8,862 | 8,128 |
11 | 1,5 | 9,5 | 10,986 | 10,732 | 9,994 | 9,862 | 9,128 |
12 | 1,75 | 10,2 | 11,966 | 11,701 | 10,829 | 10,679 | 9,819 |
14 | 2 | 12 | 13,962 | 12,682 | 12,663 | 12,503 | 11,508 |
16 | 2 | 14 | 15,962 | 15,682 | 14,663 | 14,503 | 13,508 |
18 | 2,5 | 15,5 | 17,958 | 17,623 | 16,334 | 16,164 | 14,891 |
20 | 2,5 | 17,5 | 19,958 | 19,623 | 18,334 | 18,164 | 16,891 |
22 | 2,5 | 19,5 | 21,958 | 21,623 | 20,334 | 20,164 | 18,891 |
24 | 3 | 21 | 23,952 | 23,577 | 22,003 | 21,803 | 20,271 |
27 | 3 | 24 | 26,952 | 26,577 | 25,003 | 24,803 | 23,271 |
30 | 3,5 | 26,5 | 29,947 | 29,522 | 27,674 | 27,462 | 25,653 |
33 | 3,5 | 29,5 | 32,947 | 32,522 | 30,674 | 30,462 | 28,653 |
36 | 4 | 32 | 35,940 | 35,465 | 33,342 | 33,118 | 31,033 |
39 | 4 | 35 | 38,940 | 38,465 | 36,342 | 36,118 | 34,033 |
42 | 4,5 | 37,5 | 41,937 | 41,437 | 39,014 | 38,778 | 36,416 |
45 | 4,5 | 40,5 | 44,937 | 44,437 | 42,014 | 41,778 | 39,416 |
48 | 5 | 43 | 47,929 | 47,399 | 44,681 | 44,431 | 41,795 |
52 | 5 | 47 | 51,929 | 51,399 | 48,681 | 48,431 | 45,795 |
56 | 5,5 | 50,5 | 55,925 | 55,365 | 52,353 | 52,088 | 49,177 |
60 | 5,5 | 54,5 | 59,925 | 59,365 | 56,353 | 56,088 | 53,177 |
64 | 6 | 58 | 63,920 | 63,320 | 60,023 | 59,743 | 56,559 |
68 | 6 | 62 | 67,920 | 67,320 | 64,023 | 64,743 | 60,559 |
Sources: DIN 13-1 - ISO metric threads for general use - Part 1: Nominal sizes for standard threads; nominal thread diameters from 1 mm to 68 mm DIN 13-2 - ISO metric threads for general use - Part 2: Nominal dimensions for fine pitch threads with pitches of 0.2 mm, 0.25 mm and 0.35 mm; nominal thread diameters from 1 mm to 50 mm |
UNC-Threads

Thread | Diameter | Outer Diameter | Core Hole Diameter | Threads | Pitch |
---|---|---|---|---|---|
UNC | inch | mm | mm | per inch | mm |
N 1 | 0,073 | 1,854 | 1,50 | 64 | 0,397 |
N 2 | 0,086 | 2,184 | 1,80 | 56 | 0,456 |
N 3 | 0,99 | 2,515 | 2,10 | 48 | 0,529 |
N 4 | 0,112 | 2,845 | 2,35 | 40 | 0,635 |
N 5 | 0,250 | 3,175 | 2,65 | 40 | 0,635 |
N 6 | 0,138 | 3,505 | 2,85 | 32 | 0,794 |
N 8 | 0,164 | 4,166 | 3,50 | 32 | 0,794 |
N 10 | 0,190 | 4,826 | 4,00 | 24 | 1,058 |
N 12 | 0,216 | 5,486 | 4,65 | 24 | 1,058 |
1/4" | 0,250 | 6,350 | 5,35 | 20 | 1,270 |
5/16" | 0,313 | 7,938 | 6,80 | 18 | 1,411 |
3/8" | 0,375 | 9,525 | 8,25 | 16 | 1,587 |
7/16" | 0,438 | 11,112 | 9,65 | 14 | 1,818 |
1/2" | 0,500 | 12,700 | 11,15 | 13 | 1,954 |
9/16" | 0,563 | 14,288 | 12,60 | 12 | 2,117 |
5/8" | 0,625 | 15,875 | 14,05 | 11 | 2,309 |
3/4" | 0,750 | 19,050 | 17,00 | 10 | 2,540 |
7/8" | 0,875 | 22,225 | 20,00 | 9 | 2,822 |
1" | 1,000 | 25,400 | 22,85 | 8 | 3,175 |
1 1/8" | 1,125 | 28,575 | 25,65 | 7 | 3,628 |
1 1/4" | 1,250 | 31,750 | 28,85 | 7 | 3,628 |
1 3/8" | 1,375 | 43,925 | 31,55 | 6 | 4,233 |
1 1/2" | 1,500 | 38,100 | 34,70 | 6 | 4,233 |
1 3/4" | 1,750 | 44,450 | 40,40 | 5 | 5,080 |
2" | 2,000 | 50,800 | 46,30 | 4,5 | 5,644 |
2 1/4" | 2,250 | 57,150 | 52,65 | 45 | 5,644 |
2 1/2" | 2,500 | 63,500 | 58,50 | 4 | 6,350 |
2 3/4" | 2,750 | 69,850 | 64,75 | 4 | 6,350 |
3" | 3,000 | 76,200 | 71,10 | 4 | 6,350 |
3 1/4" | 3,250 | 82,550 | 77,45 | 4 | 6,350 |
3 1/2" | 3,500 | 88,900 | 83,80 | 4 | 6,350 |
3 3/4" | 3,750 | 95,250 | 90,15 | 4 | 6,350 |
4" | 4,000 | 101,60 | 96,50 | 4 | 6,350 |
Typically, thread dimensions >= 1" are offered by the manufacturers with an 8-UN thread. |
UNF-Threads
Thread | Diameter | Outer Diameter | Core Hole Diameter | Threads | Pitch |
---|---|---|---|---|---|
UNF | inch | mm | mm | per inch | mm |
N 0 | 0,060 | 1,524 | 1,25 | 80 | 0,317 |
N 1 | 0,073 | 1,854 | 1,55 | 72 | 0,353 |
N 2 | 0,068 | 2,184 | 1,90 | 64 | 0,397 |
N 3 | 0,099 | 2,515 | 2,15 | 56 | 0,453 |
N 4 | 0,112 | 2,845 | 2,40 | 48 | 0,529 |
N 5 | 0,125 | 3,175 | 2,70 | 44 | 0,577 |
N 6 | 0,138 | 3,505 | 2,95 | 40 | 0,635 |
N 8 | 0,164 | 4,166 | 3,50 | 36 | 0,705 |
N 10 | 0,190 | 4,826 | 4,10 | 32 | 0,794 |
N 12 | 0,216 | 5,486 | 4,70 | 28 | 0,907 |
1/4" | 0,250 | 6,350 | 5,50 | 28 | 0,907 |
5/16" | 0,313 | 7,938 | 6,90 | 24 | 1,058 |
3/8" | 0,375 | 9,525 | 8,50 | 24 | 1,058 |
7/16" | 0,438 | 11,112 | 9,90 | 20 | 1,270 |
1/2" | 0,500 | 12,700 | 11,50 | 20 | 1,270 |
9/16" | 0,563 | 14,288 | 12,90 | 18 | 1,411 |
5/8" | 0,625 | 15,875 | 14,50 | 18 | 1,411 |
3/4" | 0,750 | 19,050 | 17,50 | 16 | 1,587 |
7/8" | 0,875 | 22,250 | 20,40 | 14 | 1,814 |
1" | 1,000 | 25,400 | 23,25 | 12 | 2,117 |
1 1/8" | 1,125 | 28,575 | 26,50 | 12 | 2,117 |
1 1/4" | 1,250 | 31,750 | 29,50 | 12 | 2,117 |
1 3/8" | 1,375 | 38,100 | 32,75 | 12 | 2,117 |
1 1/2" | 1,500 | 43,925 | 36,00 | 12 | 2,117 |
Typically, thread dimensions ≥ 1" with an 8-UN thread are offered by manufacturers. | |||||
Source: ASME B1.1 - Unified Inch Screw Threads |
8-UN-Threads

Thread identification | Diameter | Outer Diameter | Core Hole Diameter | Threads | Pitch |
---|---|---|---|---|---|
inch | mm | mm | per inch | mm | mm |
1 1/16" - 8UN | 1,0625 | 26,987 | 24,000 | 8 | 3,175 |
1 1/8" - 8UN | 1,1250 | 28,575 | 25,500 | 8 | 3,175 |
1 3/16" - 8UN | 1,1875 | 30,162 | 27,200 | 8 | 3,175 |
1 1/4" - 8UN | 1,2500 | 31,750 | 28,800 | 8 | 3,175 |
1 5/16" - 8UN | 1,3125 | 33,337 | 30,300 | 8 | 3,175 |
1 3/8" - 8UN | 1,3750 | 34,925 | 31,900 | 8 | 3,175 |
1 7/16" - 8UN | 1,4375 | 36,512 | 33,500 | 8 | 3,175 |
1 1/2" - 8UN | 1,5000 | 38,100 | 35,100 | 8 | 3,175 |
1 9/16"- 8UN | 1,5625 | 39,688 | 36,700 | 8 | 3,175 |
1 5/8"- 8UN | 1,6250 | 41,275 | 38,300 | 8 | 3,175 |
1 11/16"- 8UN | 1,6875 | 42,862 | 39,900 | 8 | 3,175 |
1 3/4"- 8UN | 1,7500 | 44,450 | 41,400 | 8 | 3,175 |
1 13/16"- 8UN | 1,8125 | 46,037 | 43,000 | 8 | 3,175 |
1 7/8"- 8UN | 1,8750 | 47,625 | 44,600 | 8 | 3,175 |
1 15/16"- 8UN | 1,9375 | 49,212 | 46,200 | 8 | 3,175 |
2"- 8UN | 2,0000 | 50,800 | 47,800 | 8 | 3,175 |
2 1/8"- 8UN | 2,1250 | 53,975 | 51,000 | 8 | 3,175 |
2 1/4"- 8UN | 2,2500 | 57,150 | 54,100 | 8 | 3,175 |
2 3/8"- 8UN | 2,3750 | 60,325 | 57,300 | 8 | 3,175 |
2 1/2"- 8UN | 2,5000 | 63,500 | 60,500 | 8 | 3,175 |
2 5/8"- 8UN | 2,6250 | 66,675 | 64,700 | 8 | 3,175 |
2 3/4"- 8UN | 2,7500 | 69,850 | 66,800 | 8 | 3,175 |
2 7/8"- 8UN | 2,8750 | 73,025 | 70,000 | 8 | 3,175 |
3"- 8UN | 3,0000 | 76,200 | 73,200 | 8 | 3,175 |
3 1/8"- 8UN | 3,1250 | 79,375 | 76,400 | 8 | 3,175 |
3 1/4"- 8UN | 3,2500 | 82,550 | 79,500 | 8 | 3,175 |
3 3/8"- 8UN | 3,3750 | 85,725 | 82,700 | 8 | 3,175 |
3 1/2"- 8UN | 3,5000 | 88,900 | 85,900 | 8 | 3,175 |
3 5/8"- 8UN | 3,6250 | 92,075 | 89,000 | 8 | 3,175 |
3 3/4"- 8UN | 3,7500 | 95,250 | 92,300 | 8 | 3,175 |
3 7/8"- 8UN | 3,8750 | 98,425 | 95,400 | 8 | 3,175 |
4"- 8UN | 4,0000 | 101,600 | 98,600 | 8 | 3,175 |
Source: ASME B1.1 - Unified Screw Threads |
NPT-Pipe threads

Thread Diameter | Pitch | Threads | Core Hole Diameter | Outer Diameter |
---|---|---|---|---|
NPT | mm | per inch | mm | mm |
1/16" | 0,941 | 27 | 6,00 | 7,895 |
1/8" | 0,941 | 27 | 8,25 | 10,242 |
1/4" | 1,411 | 18 | 10,70 | 13,616 |
3/8" | 1,411 | 18 | 14,10 | 17,055 |
1/2" | 1,814 | 14 | 17,40 | 21,223 |
3/4" | 1,814 | 14 | 22,60 | 26,568 |
1" | 2,209 | 11,5 | 28,50 | 33,228 |
1 1/4" | 2,209 | 11,5 | 37,00 | 41,985 |
1 1/2" | 2,209 | 11,5 | 43,50 | 48,054 |
2" | 2,209 | 11,5 | 55,00 | 60,092 |
2 1/2" | 3,175 | 8 | 65,50 | 72,699 |
3" | 3,175 | 8 | 81,50 | 88,608 |
3 1/2" | 3,175 | 8 | 94,30 | 101,316 |
4" | 3,175 | 8 | 107,00 | 113,973 |
5" | 3,175 | 8 | 134,384 | 141,300 |
6" | 3,175 | 8 | 161,191 | 168,275 |
8" | 3,175 | 8 | 211,673 | 219,075 |
10" | 1,375 | 8 | 265,311 | 273,050 |
12" | 1,375 | 8 | 315,793 | 323,850 |
1" (inch) = 25,4 mm | ||||
Source: ANSI / ASME B 1.20.1 - Universal pipe thread (inch) |
Whitworth pipe thread - G

Rohrgewinde für nicht im Gewinde dichtende Verbindungen (zylindrisch), außen = G
Thread Diameter | Pitch | Threads | Nut Diameter | Core Hole Diameter |
---|---|---|---|---|
G | mm | per inch | mm | max. |
1/8" | 0,907 | 28 | 8,85 | 8,80 |
1/4" | 1,337 | 19 | 11,89 | 11,80 |
3/8" | 1,337 | 19 | 15,39 | 15,25 |
1/2" | 1,814 | 14 | 19,17 | 19,00 |
5/8" | 1,814 | 14 | 21,13 | 21,00 |
3/4" | 1,814 | 14 | 24,66 | 24,50 |
7/8" | 1,814 | 14 | 28,42 | 28,25 |
1" | 2,309 | 11 | 30,93 | 30,75 |
1 1/8" | 2,309 | 11 | 35,58 | 35,30 |
1 1/4" | 2,309 | 11 | 39,59 | 39,25 |
1 3/8" | 2,309 | 11 | 42 | 41,70 |
1 1/2" | 2,309 | 11 | 45,48 | 45,25 |
1 3/4" | 2,309 | 11 | 51,43 | 51,10 |
2" | 2,309 | 11 | 57,29 | 57,00 |
2 1/4" | 2,309 | 11 | 63,39 | 63,10 |
2 1/2" | 2,309 | 11 | 72,86 | 72,60 |
2 3/4" | 2,309 | 11 | 79,21 | 78,90 |
3" | 2,309 | 11 | 85,56 | 85,30 |
3 1/4" | 2,309 | 11 | 91,66 | 91,50 |
3 1/2" | 2,309 | 11 | 98,01 | 97,70 |
3 3/4" | 2,309 | 11 | 104,30 | 104,00 |
4" | 2,309 | 11 | 110,71 | 110,40 |
1" (inch) ) 25,4 mm |
Whitworth pipe thread - R

Whitworth taper pipe thread.
Whitworth pipe thread for threaded pipes and fittings. Cylindrical female thread and tapered (taper 1 :16) male thread. A suitable sealant may be used in the thread to ensure a tight connection.
Outer Thread | Inner Thread | Nominal Size Pipe | Pitch | Threads | Outer Diameter | Core Hole Diameter |
---|---|---|---|---|---|---|
R | Rp | mm | mm | per inch | mm | mm |
1/16" | 1/16" | 3 | 0,907 | 28 | 7,723 | 6,561 |
1/8" | 1/8" | 6 | 0,907 | 28 | 9,728 | 8,566 |
1/4" | 1/4" | 8 | 1,337 | 19 | 13,157 | 11,445 |
3/8" | 3/8" | 10 | 1,337 | 19 | 16,662 | 14,950 |
1/2" | 1/2" | 15 | 1,814 | 14 | 20,995 | 18,631 |
3/4" | 3/4" | 20 | 1,817 | 14 | 26,441 | 24,117 |
1" | 1" | 25 | 2,309 | 11 | 33,249 | 30,291 |
1 1/4" | 1 1/4" | 32 | 2,309 | 11 | 41,910 | 38,952 |
1 1/2" | 1 1/2" | 40 | 2,309 | 11 | 47,803 | 44,845 |
2" | 2" | 50 | 2,309 | 11 | 59,614 | 56,656 |
2 1/2" | 2 1/2" | 65 | 2,309 | 11 | 75,184 | 72,226 |
3" | 3" | 80 | 2,309 | 11 | 87,884 | 84,926 |
4" | 4" | 100 | 2,309 | 11 | 113,03 | 110,072 |
5" | 5" | 125 | 2,309 | 11 | 138,43 | 135,472 |
6" | 6" | 150 | 2,309 | 11 | 163,83 | 160,872 |
1" (inch) = 25,4 mm | ||||||
Sources: DIN EN ISO 228-1 - Pipe threads for non-threaded connections - Part 1: Dimensions, tolerances and designation DIN 2999-1 - Whitworth pipe threads for threaded pipes and fittings; cylindrical internal thread and tapered external thread; thread dimensions |
Round threads

Thread | Outer Diameter | Bolt Diameter | Core Hole Diameter | Pitch | Threads |
Rd | Rp | mm | mm | mm | per inch |
8 | 8,254 | 5,46 | 5,714 | 2,54 | 10 |
9 | 9,254 | 6,46 | 6,714 | 2,54 | 10 |
10 | 10,254 | 7,46 | 7,714 | 2,54 | 10 |
11 | 11,254 | 8,46 | 8,714 | 2,54 | 10 |
12 | 12,254 | 9,46 | 9,714 | 2,54 | 10 |
14 | 14,318 | 10,825 | 11,142 | 3,175 | 8 |
16 | 16,318 | 14,166 | 12,825 | 3,175 | 8 |
18 | 18,318 | 14,825 | 14,142 | 3,175 | 8 |
20 | 20,318 | 16,825 | 17,142 | 3,175 | 8 |
22 | 22,318 | 18,825 | 19,142 | 3,175 | 8 |
24 | 24,318 | 20,825 | 21,142 | 3,175 | 8 |
28 | 28,318 | 24,825 | 25,142 | 3,175 | 8 |
30 | 30,318 | 26,825 | 27,142 | 3,175 | 8 |
32 | 32,818 | 28,825 | 29,142 | 3,175 | 8 |
34 | 34,318 | 30,825 | 31,142 | 3,175 | 8 |
36 | 36,318 | 32,825 | 33,142 | 3,175 | 8 |
38 | 38,318 | 34,825 | 35,142 | 3,175 | 8 |
40 | 40,423 | 35,767 | 36,190 | 4,233 | 6 |
42 | 42,423 | 37,767 | 38,190 | 4,233 | 6 |
44 | 44,423 | 39,767 | 40,190 | 4,233 | 6 |
46 | 46,423 | 41,767 | 42,190 | 4,233 | 6 |
48 | 48,423 | 43,767 | 44,190 | 4,233 | 6 |
50 | 50,423 | 45,767 | 46,190 | 4,233 | 6 |
1" (inch) = 25,4 mm | |||||
Source: DIN 405-1 - Round thread for general use - Part 1: Thread profiles, nominal dimensions |
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