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Tolerances for Holes (ISO 286-2)

The importance of holes on a cnc machined parts is no less than the threads. Parts are usually made to assemble with other ones. When it talks about assembly, the standards tolerances below takes important roles on it. In other words, the relationship between the two mating parts could be determined by "fitting". Generally speaking, there are three kinds of fitting below:

 

1.) transition fitting

A transition fitting is known as a slip or push fit for the mating parts. This kind of fitting is usually required a highly accurate alignment or tolerance between the mating parts. Under a transition fitting, the mating parts could perform a fitting without excess play or movement in the assembly.

 

2.) interference fitting

An interference fitting is so called press fit, tight fit or friction fit. It is usually used in fixing the bearing on to a shaft or a hole, a dowel pin into a hole. It may sometimes use to assembly spare parts into a single unit to reduce the raw material and production cost.

 

Besides, considering an optimize performance on fixing the bearing into the hole, the hole finished with burnishing process could provide a firm and consistence surface quality. You could refer to Sandy Munro's comments on the motor of Tesla Model S Plaid at 8'28''.

 

3.) slide fitting

The slide fitting is so called clearance fit or loose mating. The mating parts with a slide fitting could slide in and out without any restriction. A grinding process would be helpful to optimize the surface quality on the mating parts to slide freely between each other.

 

 

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 +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
-50
-90
160 180 +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
-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 +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
-63
-109
225 250 +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
-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 +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
-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 +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
-93
-150

Tolerances for Shafts (ISO 286-2)

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
+40
0
+60
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 -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
+90
+65
+125
+100
+140
+100
160 180 -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
+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 -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
+109
+80
+159
+130
+176
+130
225 250 -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
+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 -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
+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 -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
+150
+114
+244
+208
+265
+208
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