3.
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Knuckle thread
Rd
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NOMINAL PITCH DIAMETER d2 & D2
d2/D2 = d/D – PDn (PDn = 0.5P)
EXTERNAL THREAD INTERNAL THREAD
P = Pitch
d = Major diameter D = Major diameter
= Flank angle
O
d2 = Pitch diameter D2 = Pitch diameter 30
d1 = Minor diameter D1 = Minor diameter
Ref.: DIN 405 Part 1 (Knuckle thread – Profiles, basic sizes, general plan) & DIN 405 Part 2 (Deviations and
tolerances) These DIN standards contain much more information than is given here.
Denomination T.P.I. P Pitch diameter Denomination T.P.I. P Pitch diameter
Rd Thread Per Rd Thread Per
Inch (mm) D2 / d2 Inch (mm) D2 / d2
column1 column2 column1 column2
8 10 2,540 6,730 75 6 4,233 72,883
9 10 2,540 7,730 78 6 4,233 75,883
10 10 2,540 8,730 80 6 4,233 87,883
11 10 2,540 9,730 82 6 4,233 79,883
12 10 2,540 10,730 85 6 4,233 82,883
14 8 3,175 12,412 88 6 4,233 85,883
16 8 3,175 14,412 90 6 4,233 87,883
18 8 3,175 16,412 92 6 4,233 89,883
20 8 3,175 18,412 95 6 4,233 92,883
22 8 3,175 20,412 98 6 4,233 95,883
24 8 3,175 22,412 100 6 4,233 97,883
26 8 3,175 24,412 105 4 6,350 101,825
28 8 3,175 26,412 110 4 6,350 106,825
30 8 3,175 28,412 115 4 6,350 111,825
32 8 3,175 30,412 120 4 6,350 116,825
34 8 3,175 32,412 125 4 6,350 121,825
36 8 3,175 34,412 130 4 6,350 126,825
38 8 3,175 36,412 135 4 6,350 131,825
40 6 4,233 37,883 140 4 6,350 136,825
42 6 4,233 39,883 145 4 6,350 141,825
44 6 4,233 41,883 150 4 6,350 146,825
46 6 4,233 43,883 155 4 6,350 151,825
48 6 4,233 45,883 160 4 6,350 156,825
50 6 4,233 47,883 165 4 6,350 161,825
52 6 4,233 49,883 170 4 6,350 166,825
55 6 4,233 52,883 175 4 6,350 171,825
58 6 4,233 55,883 180 4 6,350 176,825
60 6 4,233 57,883 185 4 6,350 181,825
62 6 4,233 59,883 190 4 6,350 186,825
65 6 4,233 62,883 195 4 6,350 191,825
68 6 4,233 65,883 200 4 6,350 196,825
70 6 4,233 67,883
72 6 4,233 69,883
Column 1 is recommended over column 2
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3.10 2007/2 Page 2 - 2
Basic allowance for screw threads
To be subtracted from the nominal pitch diameter for d 2
Pitch Tolerance placement
P mm e h
2,54 - 0,078
3,175 - 0,085
0
4,233 - 0,097
6,35 - 0,120
Tolerance for pitch diameter d2 for screw (external) threads
Major diameter Pitch Tolerance size
above up to
mm mm P mm 6 7 8
7 12 2,54 + 0 / - 0,160 + 0 / - 0,200 + 0 / - 0,250
12 38 3,175 + 0 / - 0,190 + 0 / - 0,236 + 0 / - 0,300
38 100 4,233 + 0 / - 0,236 + 0 / - 0,300 + 0 / - 0,375
100 200 6,35 + 0 / - 0,315 + 0 / - 0,400 + 0 / - 0,500
Remember and include the basic allowance from the table above
Tolerance for pitch diameter D2 for nut (internal) threads
Major diameter Pitch Tolerance size
above up to
mm mm P mm 7 8
7 12 2,54 - 0 / + 0,265 - 0 / + 0,335
12 38 3,175 - 0 / + 0,315 - 0 / + 0,400
38 100 4,233 - 0 / + 0,400 - 0 / + 0,500
100 200 6,35 - 0 / + 0,530 - 0 / + 0,670
Examples
Denomination Pitch diameter Tolerance max min
Screw d2
Rd 40 x 1/6 – 7e 37,883 - 0,097 / - 0,397 37,786 37,486
Denomination Pitch diameter Tolerance max min
Nut D2
Rd 40 x 1/6 – 7H 37,883 - 0 / + 0,400 38,283 37,883
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