Internal Metric Thread Table Chart Fastener Sizes M25 - M50

ISO Metric Hardware Engineering Data
 Fastener and Screw / Bolt Design, Formula and Calculations

The following table chart are standard metric internal thread sizes M 25 - M 50 per. ANSI/ASME B1.13M-1995. These thread sizes and classes represent bolts and screws, as well, as other standard internal threads. Do not use these values for standard metric external thread design. All units in mm.

Metric Internal and External threads

Where:

H = P ( 31/2 / 2 ) = 0.866025 P
or
0.125H = 0.108253P

ISO Metric
Thread Designation
Pitch
Metric Internal Threads
Specification Table
Tolerance Class
Minor Dia
Pitch Dia
Major Dia
Tap Drill
Min
Max
Min
Max
Min
Max
Basic
M25x2
2
6H
22.835
23.210
23.701
23.925
25.000
25.513
23.000
M25x1.5
1.5
6H
23.376
23.676
24.026
24.226
25.000
25.416
23.500
M25x1
1
6H
23.917
24.153
24.350
24.520
25.000
25.314
24.000
M26x1.5
1.5
6H
24.376
24.676
25.026
25.226
26.000
26.417
24.500
M27x3
3
6H
23.752
24.252
25.051
25.316
27.000
27.698
24.000
M27x2
2
6H
24.835
25.210
25.701
25.925
27.000
27.513
25.000
M27x1.5
1.5
6H
25.376
25.676
26.026
26.226
27.000
27.417
25.500
M27x1
1
6H
25.917
26.153
26.350
26.520
27.000
27.314
26.000
M27x0.75
0.75
6H
26.188
26.378
26.513
26.663
27.000
27.258
26.250
M28x2
2
6H
25.835
26.210
26.701
26.925
28.000
28.513
26.000
M28x1.5
1.5
6H
26.376
26.676
27.026
27.226
28.000
28.417
26.500
M28x1
1
6H
26.917
27.153
27.350
27.520
28.000
28.314
27.000
M30x3.5
3.5
6H
26.211
26.771
27.727
28.007
30.000
30.785
26.500
M30x3
3
6H
26.752
27.252
28.051
28.316
30.000
30.698
27.000
M30x2.5
2.5
6H
27.294
27.744
28.376
28.626
30.000
30.611
27.500
M30x2
2
6H
27.835
28.210
28.701
28.925
30.000
30.513
28.000
M30x1.5
1.5
6H
28.376
28.676
29.026
29.226
30.000
30.416
28.500
M30x1
1
6H
28.917
29.153
29.350
29.520
30.000
30.314
29.000
M30x0.75
0.75
6H
29.188
29.378
29.513
29.663
30.000
30.258
29.250
M32x2
2
6H
29.835
30.210
30.701
30.925
32.000
32.513
30.000
M32x1.5
1.5
6H
30.376
30.676
31.026
31.226
32.000
32.417
30.500
M33x3.5
3.5
6H
29.211
29.771
30.727
31.007
33.000
33.785
29.500
M33x3
3
6H
29.752
30.252
31.051
31.316
33.000
33.698
30.000
M33x2
2
6H
30.835
31.210
31.701
31.925
33.000
33.513
31.000
M33x1.5
1.5
6H
31.376
31.676
32.026
32.226
33.000
33.417
31.500
M33x1
1
6H
31.917
32.153
32.350
32.520
33.000
33.314
32.000
M33x0.75
0.75
6H
32.188
32.378
32.513
32.663
33.000
33.258
31.250
M35x1.5
1.5
6H
33.376
33.676
34.026
34.226
35.000
35.416
33.500
M36x4
4
6H
31.670
32.270
33.402
33.702
36.000
36.877
32.000
M36x3
3
6H
32.752
33.252
34.051
34.316
36.000
36.698
33.000
M36x2
2
6H
33.835
34.210
34.701
34.925
36.000
36.513
34.000
M36x1.5
1.5
6H
34.376
34.676
35.026
35.226
36.000
36.417
34.500
M36x1
1
6H
34.917
35.153
35.350
35.520
36.000
36.314
35.000
M38x1.5
1.5
6H
36.376
36.676
37.026
37.226
38.000
38.417
36.500
M39x4
4
6H
34.670
35.270
36.402
36.702
39.000
39.877
35.000
M39x3
3
6H
35.752
36.252
37.051
37.316
39.000
39.698
36.000
M39x2
2
6H
36.835
37.210
37.701
37.925
39.000
39.513
37.000
M39x1.5
1.5
6H
37.376
37.676
38.026
38.226
39.000
39.417
37.500
M39x1
1
6H
37.917
38.153
38.350
38.520
39.000
39.314
38.000
M40x3
3
6H
36.752
37.252
38.051
38.316
40.000
40.698
37.000
M40x2.5
2.5
6H
37.294
37.744
38.376
38.626
40.000
40.611
37.500
M40x2
2
6H
37.835
38.210
38.701
38.925
40.000
40.513
38.000
M40x1.5
1.5
6H
38.376
38.676
39.026
39.226
40.000
40.416
38.500
M42x4.5
4.5
6H
37.129
37.799
39.077
39.392
42.000
42.965
37.500
M42x4
4
6H
37.670
38.270
39.402
39.702
42.000
42.877
38.000
M42x3
3
6H
38.752
39.252
40.051
40.316
42.000
42.698
39.000
M42x2
2
6H
39.835
40.210
40.701
40.925
42.000
42.513
40.000
M42x1.5
1.5
6H
40.376
40.676
41.026
41.226
42.000
42.417
40.500
M42x1
1
6H
40.917
41.153
41.350
41.520
42.000
42.314
41.000
M45x4.5
4.5
6H
40.129
40.799
42.077
42.392
45.000
45.965
41.500
M45x4
4
6H
40.670
41.270
42.402
42.702
45.000
45.877
41.000
M45x3
3
6H
41.752
42.252
43.051
43.316
45.000
45.698
42.000
M45x2
2
6H
42.835
43.210
43.701
43.925
45.000
45.513
43.000
M45x1.5
1.5
6H
43.376
43.676
44.026
44.226
45.000
45.416
43.500
M45x1
1
6H
43.917
44.153
44.350
44.520
45.000
45.314
44.000
M48x5
5
6H
42.587
43.297
44.752
45.087
48.000
49.057
43.000
M48x4
4
6H
43.670
44.270
45.402
45.717
48.000
48.892
44.000
M48x3
3
6H
44.752
45.252
46.051
46.331
48.000
48.713
45.000
M48x2
2
6H
45.835
46.210
46.701
46.937
48.000
48.525
46.000
M48x1.5
1.5
6H
46.376
46.676
47.026
47.238
48.000
48.429
46.500
M50x4
4
6H
45.670
46.270
47.402
47.717
50.000
50.892
46.000
M50x3
3
6H
46.752
47.252
48.051
48.331
50.000
50.713
47.000
M50x2
2
6H
47.835
48.210
48.701
48.937
50.000
50.525
48.000
M50x1.5
1.5
6H
48.376
48.676
49.026
49.238
50.000
50.428
48.500

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