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ISO System of Limits and Fits (Tolerances)

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Designation

Explanation

Designation

Explanation

zero line

It represents the nominal dimension that is referenced by the deviation and tolerances.

fundamental tolerance grade

A group of tolerances assigned to the same level of precision, e.g. IT7

fundamental deviation

The fundamental deviation determins the position of the tolerance zone with respect to the zero line.

tolerance grade

Number of the fundamental tolerance grade , e.g. 7 for the fundamental toleance grade IT7.

tolerance

Difference between the max. and the min. dimension or between the upper and lower deviation.

tolerance class

Name for a combination of a fundamental deviation and a tolerance grade, e.g. H7.

fundamental tolerance

A tolerance assigned to a fundamental tolerance grade, e.g. IT7 and a nominal dimension range , e.g. to 50 mm.

fit

Planned joining condition between hole and shaft.
ISO system of limits and fits
fundamental tolerances
nominal dimension in mm
micrometer (1/1000 mm)
millimeter
over
up to
IT1
IT2
IT3
IT4
IT5
IT6
IT7
IT8
IT9
IT10
IT11
IT12
IT13
IT14
IT15
IT16
IT17
IT18
-
3
0.8
1.2
2
3
4
6
10
14
25
40
60
0.1
0.14
0.25
0.4
0.6
1.0
1.4
3
6
1
1.5
2.5
4
5
8
12
18
30
48
75
0.12
0.18
0.3
0.48
0.75
1.2
1.8
6
10
1
1.5
2.5
4
6
9
15
22
36
58
90
0.15
0.22
0.36
0.58
0.9
1.5
2.2
10
18
1.2
2
3
5
8
11
18
27
43
70
110
0.18
0.27
0.43
0.7
1.1
1.8
2.7
18
30
1.5
2.5
4
6
9
13
21
33
52
84
130
0.21
0.33
0.52
0.84
1.3
2.1
3.3
30
50
1.5
2.5
4
7
11
16
25
39
62
100
160
0.25
0.39
0.62
1.0
1.6
2.5
3.9
50
80
2
3
5
8
13
19
30
46
74
120
190
0.3
0.46
0.74
1.2
1.9
3.0
4.6
80
120
2.5
4
6
10
15
22
35
54
87
140
220
0.35
0.54
0.87
1.4
2.2
3.5
5.4
120
180
3.5
5
8
12
18
25
40
63
100
160
250
0.4
0.63
1.0
1.6
2.5
4.0
6.3
180
250
4.5
7
10
14
20
29
46
72
115
185
290
0.46
0.72
1.15
1.85
2.9
4.6
7.2
250
315
6
8
12
16
23
32
52
81
130
210
320
0.52
0.81
1.3
2.1
3.2
5.2
8.1
315
400
7
9
13
18
25
36
57
89
140
230
360
0.57
0.89
1.4
2.3
3.6
5.7
8.9
400
500
8
10
15
20
27
40
63
97
155
250
400
0.63
0.97
1.55
2.5
4.0
6.3
9.7
500
630
9
11
16
22
32
44
70
110
175
280
440
0.7
1.1
1.75
2.8
4.4
7.0
11.0
630
800
10
13
18
25
36
50
80
125
200
320
500
0.8
1.25
2.0
3.2
5.0
8.0
12.5
800
1000
11
15
21
28
40
56
90
140
230
360
560
0.9
1.4
2.3
3.6
5.6
9.0
14.0
1000
1250
13
18
24
33
47
66
105
165
260
420
660
1.05
1.65
2.6
4.2
6.6
10.5
16.5
1250
1600
15
21
29
39
55
78
125
195
310
500
780
1.25
1.95
3.1
5.0
7.8
12.5
19.5
1600
2000
18
25
35
46
65
92
150
230
370
600
920
1.5
2.3
3.7
6.0
9.2
15.0
23.0
2000
2500
22
30
41
55
78
110
175
280
440
700
1100
1.75
2.8
4.4
7.0
11.0
17.5
28.0
2500
3150
26
36
50
68
96
135
210
330
540
860
1350
2.1
3.3
5.4
8.6
13.5
21.0
33.0
do not use IT14 to IT18 for nominal dimensions of 1 mm and below
ISO system of limits and fits
basic shaft system
upper and lower limits in micrometer (0.001 mm)
over
up to
d9
e8
f7
g6
h5
h6
h7
h8
h9
h11
js5
js6
js13
js14
k5
k6
m5
m6
n5
n6
p6
r6
s6
s7
-
3
- 20
- 45
- 14
- 28
- 6
- 16
- 2
- 8
0
- 4
0
- 6
0
- 10
0
- 14
0
- 25
0
- 60
+ 2
- 2
+ 3
- 3
+ 70
- 70
+ 125
- 125
+ 4
0
+ 6
0
+ 6
+ 2
+ 8
+ 2
+ 8
+ 4
+ 10
+ 4
+ 12
+ 6
+ 16
+ 10
+ 20
+ 14
+ 24
+ 14
3
6
- 30
- 60
- 20
-38
- 10
- 22
- 4
-12
0
- 5
0
- 8
0
- 12
0
- 18
0
-30
0
- 75
+ 2.5
- 2.5
+ 4
- 4
+ 90
- 90
+ 150
- 150
+ 6
+ 1
+ 9
+ 1
+ 9
+ 4
+ 12
+ 4
+13
+ 8
+ 16
+ 8
+ 20
+ 12
+ 23
+ 15
+ 27
+ 19
+ 31
+ 19
6
10
- 40
- 76
- 25
- 47
- 13
- 28
- 5
- 14
0
- 6
0
- 9
0
- 15
0
- 22
0
- 36
0
- 90
+ 3
- 3
+ 4.5
- 4.5
+ 110
-110
+ 180
- 180
+ 7
+ 1
+ 10
+ 1
+ 12
+ 6
+ 15
+ 6
+ 16
+ 10
+ 19
+ 10
+ 24
+ 15
+ 28
+ 19
+ 32
+ 23
+ 38
+23
10
18
- 50
- 93
- 32
- 59
- 16
- 34
- 6
- 17
0
- 8
0
- 11
0
- 18
0
- 27
0
- 43
0
- 110
+ 4
- 4
+ 5.5
- 5.5
+ 135
- 135
+ 215
- 215
+ 9
+ 1
+ 12
+ 1
+ 15
+ 7
+ 18
+ 7
+ 20
+ 12
+ 23
+ 12
+ 29
+ 18
+ 34
+ 23
+ 39
+ 28
+ 46
+28
18
30
- 65
-117
- 40
- 73
- 20
- 41
- 7
- 20
0
- 9
0
- 13
0
- 21
0
- 33
0
- 52
0
- 130
+ 4.5
- 4.5
+ 6.5
- 6.5
+ 165
- 165
+ 260
- 260
+ 11
+ 2
+ 15
+ 2
+ 17
+ 8
+ 21
+ 8
+ 24
+ 15
+ 28
+ 15
+ 35
+ 22
+ 41
+ 28
+ 48
+ 35
+ 56
+ 35
30
50
- 80
- 142
- 50
- 89
- 25
- 50
- 9
- 25
0
- 11
0
- 16
0
- 25
0
- 39
0
- 62
0
- 160
+ 5.5
- 5.5
+ 8
- 8
+ 195
- 195
+ 310
- 310
+ 13
+ 2
+ 18
+ 2
+ 20
+ 9
+ 25
+ 9
+ 28
+ 17
+ 33
+ 17
+ 42
+ 26
+ 50
+ 34
+ 59
+ 43
+ 68
+ 43
50
65
- 100
- 174
- 60
- 106
- 30
- 60
- 10
- 29
0
- 13
0
- 19
0
- 30
0
- 46
0
- 74
0
- 190
+ 6.5
- 6.5
+ 9.5
- 9.5
+ 230
- 230
+ 370
- 370
+ 15
+ 2
+ 21
+ 2
+ 24
+ 11
+ 30
+ 11
+ 33
+ 20
+ 39
+ 20
+ 51
+ 32
+ 60
+ 41
+ 72
+ 53
+ 83
+ 53
65
80
- 100
- 174
- 60
- 106
- 30
- 60
- 10
- 29
0
- 13
0
- 19
0
- 30
0
- 46
0
- 74
0
- 190
+ 6.5
- 6.5
+ 9.5
- 9.5
+ 230
- 230
+ 370
- 370
+ 15
+ 2
+ 21
+ 2
+ 24
+ 11
+ 30
+ 11
+ 33
+ 20
+ 39
+ 20
+ 51
+ 32
+ 62
+ 43
+ 78
+ 59
+ 89
+ 59
80
100
- 120
- 207
- 72
- 126
- 36
- 71
- 12
- 34
0
- 15
0
- 22
0
- 35
0
- 54
0
- 87
0
- 220
+ 7.5
- 7.5
+ 11
- 11
+ 270
- 270
+ 435
- 435
+ 18
+ 3
+ 25
+ 3
+ 28
+ 13
+ 35
+ 13
+ 38
+ 23
+ 45
+ 23
+ 59
+ 37
+ 73
+ 51
+ 93
+ 71
+ 106
+ 71
100
120
- 120
- 207
- 72
- 126
- 36
- 71
- 12
- 34
0
- 15
0
- 22
0
- 35
0
- 54
0
- 87
0
- 220
+ 7.5
- 7.5
+ 11
- 11
+ 270
- 270
+ 435
- 435
+ 18
+ 3
+ 25
+ 3
+ 28
+ 13
+ 35
+ 13
+ 38
+ 23
+ 45
+ 23
+ 59
+ 37
+ 76
+ 54
+ 101
+ 79
+ 114
+ 79
120
140
-145
- 245
- 85
- 148
- 43
- 83
- 14
- 39
0
- 18
0
- 25
0
- 40
0
- 63
0
- 100
0
- 250
+ 9
- 9
+ 12.5
- 12.5
+ 315
- 315
+ 500
- 500
+ 21
+ 3
+ 28
+ 3
+ 33
+ 15
+ 40
+ 15
+ 45
+ 27
+ 52
+ 27
+ 68
+ 43
+ 88
+ 63
+ 117
+ 92
+ 132
+ 92
140
160
+ 90
+ 65
+ 125
+ 100
+ 140
+ 100
160
180
+ 93
+ 68
+ 133
+ 108
+ 148
+ 108
180
200
- 170
- 285
- 100
- 172
- 50
- 96
- 15
- 44
0
- 20
0
- 29
0
- 46
0
- 72
0
- 115
0
- 290
+ 10
- 10
+ 14.5
- 14.5
+ 360
- 360
+ 575
- 575
+ 24
+ 4
+ 33
+ 4
+ 37
+ 17
+ 46
+ 17
+ 51
+ 31
+ 60
+ 31
+ 79
+ 50
+ 106
+ 77
+ 151
+ 122
+ 168
+ 122
200
225
+ 109
+ 80
+ 159
+ 130
+ 176
+ 130
225
250
+ 113
+ 84
+ 169
+ 140
+ 186
+ 140
250
280
-190
- 320
- 110
- 191
- 56
- 108
- 17
- 49
0
- 23
0
- 32
0
- 52
0
- 81
0
- 130
0
- 320
+ 11.5
- 11.5
+ 16
- 16
+ 405
- 405
+ 650
- 650
+ 27
+ 4
+ 36
+ 4
+ 43
+ 20
+ 52
+ 20
+ 57
+ 34
+ 66
+ 34
+ 88
+ 56
+ 126
+ 94
+ 190
+ 158
+ 210
+ 158
280
315
+ 130
+ 98
+ 202
+ 170
+ 222
+ 170
315
355
- 210
-350
- 125
- 214
- 62
- 119
- 18
- 54
0
- 25
0
- 36
0
- 57
0
- 89
0
- 140
0
- 360
+ 12.5
- 12.5
+ 18
- 18
+ 445
- 445
+ 700
- 700
+ 29
+ 4
+ 40
+ 4
+ 46
+ 21
+ 57
+ 21
+ 62
+ 37
+ 73
+ 37
+ 98
+ 62
+ 144
+ 108
+ 226
+ 190
+ 247
+ 190
355
400
+ 150
+ 114
+ 244
+ 208
+ 265
+ 208
ISO system of limits and fits
basic hole system
upper and lower limits in micrometer (0.001 mm)
over
up to
D10
E9
F7
F8
G7
G9
H6
H7
H8
H9
H11
H12
H13
JS7
JS9
K6
K7
M6
M7
N7
N9
P7
P9
R7
-
3
+ 60
+ 20
+ 39
+ 14
+ 16
+ 6
+ 20
+ 10
+ 12
+ 2
+ 27
+ 2
+ 6
0
+ 10
0
+ 14
0
+ 25
0
+ 60
0
+ 100
0
+ 140
0
+5
- 5
+ 12.5
- 12.5
0
- 6
0
- 10
- 2
- 8
- 2
- 12
- 4
- 14
- 4
- 29
- 6
- 16
- 6
- 31
- 10
- 20
3
6
+ 78
+ 30
+ 50
+ 20
+ 22
+ 10
+ 28
+ 10
+ 16
+ 4
+ 34
+ 4
+ 8
0
+ 12
0
+ 18
0
+ 30
0
+ 75
0
+ 120
0
+ 180
0
+ 6
- 6
+ 15
- 15
+ 2
- 6
+ 3
- 9
- 1
- 9
0
- 12
- 4
- 16
0
- 30
- 8
- 20
- 12
- 42
- 11
- 23
6
10
+ 98
+ 40
+ 61
+ 25
+ 28
+ 13
+ 35
+ 13
+ 20
+ 5
+ 41
+ 5
+ 9
0
+ 15
0
+ 22
0
+ 36
0
+ 90
0
+ 150
0
+ 220
0
+ 7.5
- 7.5
+ 18
-18
+ 2
- 7
+ 5
- 10
- 3
- 12
0
- 15
- 4
- 19
0
- 36
- 9
- 24
- 15
- 51
- 13
- 28
10
18
+ 120
+ 50
+ 75
+ 32
+ 34
+ 16
+ 43
+ 16
+ 24
+ 6
+ 49
+ 6
+ 11
0
+ 18
0
+ 27
0
+ 43
0
+ 110
0
+ 180
0
+ 270
0
+ 9
- 9
+ 21.5
- 21.5
+ 2
- 9
+ 6
- 12
- 4
-15
0
- 18
- 5
- 23
0
- 43
- 11
- 29
- 18
- 61
- 16
- 34
18
30
+ 149
+ 65
+ 92
+ 40
+ 41
+ 20
+ 53
+ 20
+ 28
+ 7
+ 59
+ 7
+ 13
0
+ 21
0
+ 33
0
+ 52
0
+ 130
0
+ 210
0
+ 330
0
+ 10.5
- 10.5
+ 26
- 26
+ 2
- 11
+ 6
- 15
- 4
- 17
0
- 21
- 7
- 28
0
- 52
- 14
- 35
- 22
- 74
- 20
- 41
30
50
+ 180
+80
+ 112
+ 50
+ 50
+ 25
+ 64
+ 25
+ 34
+ 9
+ 71
+ 9
+ 16
0
+ 25
0
+ 39
0
+ 62
0
+ 160
0
+ 250
0
+ 390
0
+ 12.5
- 12.5
+ 31
- 31
+ 3
- 13
+ 7
- 18
- 4
- 20
0
- 25
- 8
-33
0
- 62
- 17
- 42
- 26
- 88
- 25
-50
50
65
+ 220
+ 100
+ 134
+ 60
+ 60
+ 30
+ 76
+ 30
+ 40
+ 10

+ 19
0
+ 30
0
+ 46
0
+ 74
0
+ 190
0
+ 300
0
+ 460
0
+ 15
- 15
+ 37
- 37
+ 4
- 15
+ 9
- 21
- 5
- 24
0
- 30
- 9
- 39
0
- 74
- 21
- 51
- 32
- 106
- 30
- 60
65
80
+ 220
+ 100
+ 134
+ 60
+ 60
+ 30
+ 76
+ 30
+ 40
+ 10

+ 19
0
+ 30
0
+ 46
0
+ 74
0
+ 190
0
+ 300
0
+ 460
0
+ 15
- 15
+ 37
- 37
+ 4
- 15
+ 9
- 21
- 5
- 24
0
- 30
- 9
- 39
0
- 74
- 21
- 51
- 32
- 106
- 32
- 62
80
100
+ 260
+ 120
+ 159
+ 72
+ 71
+ 36
+ 90
+ 36
+ 47
+ 12

+ 22
0
+ 35
0
+ 54
0
+ 87
0
+ 220
0
+ 350
0
+ 540
0
+ 17.5
- 17.5
+ 43.5
- 43.5
+ 4
- 18
+ 10
- 25
- 6
- 28
0
- 35
- 10
- 45
0
- 87
- 24
- 59
- 37
- 124
- 38
- 73
100
120
+ 260
+ 120
+ 159
+ 72
+ 71
+ 36
+ 90
+ 36
+ 47
+ 12

+ 22
0
+ 35
0
+ 54
0
+ 87
0
+ 220
0
+ 350
0
+ 540
0
+ 17.5
- 17.5
+ 43.5
- 43.5
+ 4
- 18
+ 10
- 25
- 6
- 28
0
- 35
- 10
- 45
0
- 87
- 24
- 59
- 37
- 124
- 41
- 76
120
140
+ 305
+ 145
+ 185
+ 85
+ 83
+ 43
+ 106
+ 43
+ 54
+ 14

+ 25
0
+ 40
0
+ 63
0
+ 100
0
+ 250
0
+ 400
0
+ 630
0
+ 20
- 20
+ 50
- 50
+ 4
- 21
+ 12
- 28
- 8
- 33
0
- 40
- 12
- 52
0
- 100
- 28
- 68
- 43
- 143
- 48
- 88
140
160
- 50
- 90
160
180
- 53
- 93
180
200
+ 335
+ 170
+ 215
+ 110
+ 96
+ 50
+ 122
+ 50
+ 61
+ 15

+ 29
0
+ 46
0
+ 72
0
+ 115
0
+ 290
0
+ 460
0
+ 720
0
+ 23
- 23
+ 57.5
- 57.5
+ 5
- 24
+ 13
- 33
- 8
- 37
0
- 46
- 14
- 60
0
- 115
- 33
- 79
- 50
- 165
- 60
- 106
200
225
- 63
- 109
225
250
- 67
- 113
250
280
+ 400
+ 190
+ 240
+ 110
+ 108
+ 56
+ 137
+ 56
+ 69
+ 17

+ 32
0
+ 52
0
+ 81
0
+ 130
0
+ 320
0
+ 520
0
+ 810
0
+ 26
- 26
+ 65
- 65
+ 5
- 27
+ 16
- 36
- 9
- 41
0
- 52
- 14
- 66
0
- 130
- 36
- 88
- 56
- 186
- 74
- 126
280
315
- 78
- 130
315
355
+ 440
+ 210
+ 265
+ 125
+ 119
+ 62
+ 151
+ 62
+ 75
+ 18

+ 36
0
+ 57
0
+ 89
0
+ 140
0
+ 360
0
+ 570
0
+ 890
0
+ 28.5
- 28.5
+ 70
- 70
+ 7
- 29
+ 17
- 40
-10
- 46
0
- 57
- 16
- 73
0
- 140
- 41
- 98
- 62
- 202
- 87
- 144
355
400
- 93
- 150
do not use N9 for nominal dimensions of 1 mm or below

recommended fits

basic hole
clearance fits
basic shaft
H8/d9

loose running fit: clearance allows for loose fit of parts
D10/h9
H8/e8

free running fit: sufficient clearance is allowed for ease of assembly
E9/h9
H8/f7

close running fit: clearance allows for parts to be easily assembled by hand while maintaining location accuracy
F8/h9
H7/f7

sliding fit - free: clearance allows accurate location and free movement, including turning
F8/h6
H7/g6

sliding fit - constrained: cleaance allows better location accuracy while still allowing sliding or turning movement
G7/h6
H8/h9

minimal clearance fit: allows location accuracy and hand force assembly without being a snug fit
H8/h9
H7/h6

locational clearance fit: Allows snug fit of stationary parts that may be assembled by hand force
H7/h6

transition fits

H7/j6

locational transition fit: for accurate location allowing more clearance than interference
not specified
H7/n6

locational transition fit - interference: For accurate location where interference is permissible

interference fits

H7/r6

locational interference fit: for rigidity and alignment/accurate location without special bore requirements
not specified
H7/s6

medium drive fit: for ordinary steel parts or shrink fits of light sections, tightest fit possible for cast iron
H8/u8

force fit: for parts fitting that can withstand high mechanical pressing force or shrink fitting
H8/x8

extreme force fit: for parts that can only be assembled by stretching or shrinking
general tolerances for linear and angular dimensions
tolerances for cutting and forming processes

linear dimensions mm

tolerance class
0.5 to 3
over 3 to 6
over 6 to 30
over 30 to 120
over 120 to 400
over 400 to 1000
over 1000 to 2000
over 2000 to 4000

f (fine)
+/- 0.05
+/- 0.05
+/- 0.1
+/- 0.15
+/- 0.2
+/- 0.3
+/- 0.5
-

m (medium)
+/- 0.1
+/- 0.1
+/- 0.2
+/- 0.3
+/- 0.5
+/- 0.8
+/- 1.2
+/- 2.0

c (coarse)
+/- 0.2
+/- 0.3
+/- 0.5
+/- 0.8
+/- 1.2
+/- 2.0
+/- 3.0
+/- 4.0

v (very coarse)
-
+/- 0.5
+/- 1.0
+/- 1.5
+/- 2.5
+/- 4.0
+/- 6.0
+/- 8.0

radii and chamfers
angular dimensions (nominal dimensions for the shorter angle leg)

0.5 to 3
over 3 to 6
over 6
up to 10
over 10 to 50
over 50 to 120
over 120 to 400
over 400

f (fine)
+/- 0.2
+/- 0.5
+/- 1.0
+/- 1°
+/- 0° 30'
+/- 0° 20'
+/- 0° 10'
+/- 0° 5'

m (medium)

c (coarse)
+/- 0.4
+/- 1.0
+/- 2.0
+/- 1° 30'
+/- 1°
+/- 0° 30'
+/- 0° 15'
+/- 0° 10'

v (very coarse)
+/- 3°
+/- 2°
+/- 1°
+/- 0° 30'
+/- 0° 20'

general tolerances for shape and position

straightness and flatness
nominal dimensions in mm
circular runout

up to 10
over 10 to 30
over 30 to 100
over 100 to 300
over 300 to 1000
over 1000 to 3000

H
0.02
0.05
0.1
0.2
0.3
0.4
0.1

K
0.05
0.1
0.2
0.4
0.6
0.8
0.2

L
0.1
0.2
0.4
0.8
1.2
1.6
0.5

perpendicularity (nominal dimensions for the shorter leg)
symmetry

up to 100
over 100 to 300
over 300 to 1000
over 1000 to 3000
up to 100
over 100 to 300
over 300 to 1000
over 1000 to 3000

H
0.2
0.3
0.4
0.5
0.5
0.5
0.5
0.5

K
0.4
0.6
0.8
1.0
0.6
0.6
0.8
1.0

L
0.6
1.0
1.5
2.0
0.6
1.0
1.5
2.0
Home

Recommended books:
Europa Lehrmittel, Mechanical and Metal Trades Handbook, ISBN 978-3-8085-1913-4
Europa Lehrmittel, Fachkunde Metall, ISBN 978-3-8085-1156-5
Europa Lehrmittel, Tabellenbuch Metall, ISBN 978-3-8085-1725-3
SNV Normenauszug, ISBN 978-3-03709-049-7

Robert Pfeffer
CH-8194 Hüntwangen
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