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Engineer Tools: Bolt Fastener and Holes Chart ISO 286

Engineer Tool: Bolt Fastener and Holes Chart ISO 286
Engineer Tools: Bolt Fastener and Holes Chart ISO 286
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ISO 286 provides a standardized system for tolerances, deviations, and fits for holes and shafts, including bolt fasteners common in CNC machining. The ISO 286 system ensures component compatibility, minimizing issues such as excessive friction, vibration, or wear.

Hole Tolerances for Internal Features

  • ISO 286 defines tolerance grades and limit deviations for holes. These tolerances are important for ensuring proper fits between bolts and holes.
  • Tolerance grades are denoted by letters, such as H, G, etc. H is the most common for holes. 
    • H7 is a standard tolerance grade for holes, often found in clearance fits.
    • The specific hole range depends on its nominal diameter and tolerance grade.

Bolt Tolerances for External Features

  • Typically manufactured with tolerances that align with the ISO 286 system for shafts.
  • Tolerance grades for bolts are generally denoted by lowercase letters, such as g, h, etc. 
    • G6 or H6 are common tolerance grades for bolts. Using these ensures a proper fit with the corresponding hole.

Nominal Hole Sizes and Tolerances

  • ISO 286 provides tables for nominal hole sizes and their corresponding tolerances.
    • For example, nominal hole sizes range from 3 mm to 400 mm. The tolerances are specified in micrometers (µm) based on the tolerance grade.

Bolt Fastener and Holes Chart ISO 286

These are ISO Tolerance Charts for bolts and holes per ISO 286 standards. 

Note: These charts do not compensate for position or other GD&T location tolerances.

Tolerance Zone in mm (Bolt - External Features)

Size (Over) Size (To) m6 h6 h8 h10 h11 h13 h14 h15 h16

0
1
+0.002 +0.008
0 -0.006
0 -0.014
0 -0.040
0 -0.060
0 -0.14
1
3
+0.002 +0.008
0 -0.006
0 -0.014
0 -0.040
0 -0.060
0 -0.14
0 -0.25
0 -0.40
0 -0.60
3
6
+0.004 +0.012
0 -0.008
0 -0.018
0 -0.048
0 -0.075
0 -0.18
0 -0.30
0 -0.48
0 -0.75
6
10
+0.006 +0.015
0 -0.009
0 -0.022
0 -0.058
0 -0.090
0 -0.22
0 -0.36
0 -0.58
0 -0.90
10
18
+0.007 +0.018
0 -0.011
0 -0.027
0 -0.070
0 -0.110
0 -0.27
0 -0.43
0 -0.70
0 -1.10
18
30
+0.008 +0.021
0 -0.030
0 -0.033
0 -0.084
0 -0.130
0 -0.33
0 -0.52
0 -0.84
0 -1.30
30
50
0 -0.39
0 -0.62
0 -1.00
0 -01.60
50
80
0 -0.46
0 -0.74
0 -1.20
0 -1.90
80
120
0 -0.54
0 -0.87
0 -1.40
0 -2.20

Tolerance Zone in mm (Bolt-External Features)

Size (Over) Size (To) js14 js15 js16 js17
1
3
+0.125
+0.20
+0.30
+0.50
3
6
+0.15
+0.24
+0.375
+0.60
6
10
+0.18
+0.29
+0.45
+0.75
10
18
+0.215
+0.35
+0.55
+0.90
18
30
+0.26
+0.42
+0.65
+1.05
30
50
+0.31
+0.50
+0.80
+1.25
50
80
+0.37
+0.60
+0.95
+1.50
80
120
+0.435
+0.70
+1.10
+1.75
120
180
+0.50
+0.80
+1.25
+2.00
180
250
+0.575
+0.925
+1.45
+2.30
250
315
+0.65
+1.05
+1.60
+2.60
315
400
+0.70
+1.15
+1.80
+2.85
400
500
+0.775
+1.25
+2.00
+3.15

Tolerance Zone in mm (Internal Hole Features)

Size (Over) Size (To) H7 H8 H9 H11 H13 H14

0
1
+0.010
0
+0.014
0
+0.025
0
+0.060
0
+0.14
0
1
3
+0.010
0
+0.014
0
+0.025
0
+0.060
0
+0.14
0
+0.25
0
3
6
+0.012
0
+0.018
0
+0.030
0
+0.075
0
+0.18
0
+0.30
0
6
10
+0.015
0
+0.022
0
+0.036
0
+0.090
0
+0.22
0
+0.36
0
10
18
+0.018
0
+0.027
0
+0.043
0
+0.110
0
+0.27
0
+0.43
0
18
30
+0.021
0
+0.033
0
+0.052
0
+0.130
0
+0.33
0
+0.52
0
30
50
+0.39
0
+0.62
0
50
80
+0.46
0
+0.74
0
80
120
+0.54
0
+0.87
0

The content on this blog post is for informational purposes only. Prototek does not make any declaration or guarantee, whether expressed or implied, regarding the information’s accuracy, completeness, or validity. Any performance parameters, geometric tolerances, specific design features, quality and types of materials, or processes should not be assumed to represent what will be delivered by third-party suppliers or us. It’s crucial to note that buyers seeking quotes for parts are responsible for defining the specific requirements for their project.

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