M8 X 0.75 - Basic Thread Dimensions

Property mm Inch
Nominal Diameter 8 0.315
Pitch (Distance) 0.75 0.0295
Pitch Diameter 7.513 0.2958
Minor Diameter 7.188 0.283
Thread Height 0.406 0.016
Addendum 0.244 0.0096
Crest (External)
Root (Internal)		 0.094 0.0037
Tap Drill Size
(75% depth)		 7.27 0.286
Lead Angle
(Single Start)		 1.82°
Thread Family Metric Fine Pitch (MF)
Relevant Standards ISO 68-1, ISO 9651-1, ISO 965-2, ISO 261,DIN 13
Equivalent Inch Thread5/16 - 32 UNEF

For more threading data scroll down, or use the Thread Calculator

Table of Content

M8 X 0.75 Possible Thread Classes

External Threads

Choose tolerance class: 4g, 4h, 6e, 6g, 6h, 5g4g, 5h4h, 5g6g, 7g6g, 7h6h, 7e6e

Metric ISO External Thread - Tolerance sketch

Internal Threads

Choose tolerance class: 4H, 5H, 5G, 6H, 6G, 7H, 7G

Metric ISO Internal Thread - Tolerance sketch

M8 X 0.75 4g (External)

* Permisable values for thread Class 4g

# Description Value (mm) Value (Inch)
es Allowance 0.022 (Ref) 0.0009 (Ref)
d Major Diameter 7.888 - 7.978 0.3106 - 0.3141
d2 Pitch Diameter 7.428 - 7.491 0.2924 - 0.2949
R Root Radius 0.094 (Min) 0.0037 (Min)
C Root Truncation 0.094 - 0.184 0.0037 - 0.0072
LE Normal Length of Engagement 2.4 - 7.1 0.0945 - 0.2795

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M8 X 0.75 4h (External)

* Permisable values for thread Class 4h

# Description Value (mm) Value (Inch)
es Allowance 0 (Ref) 0 (Ref)
d Major Diameter 7.91 - 8 0.3114 - 0.315
d2 Pitch Diameter 7.45 - 7.513 0.2933 - 0.2958
R Root Radius 0.094 (Min) 0.0037 (Min)
C Root Truncation 0.094 - 0.184 0.0037 - 0.0072
LE Normal Length of Engagement 2.4 - 7.1 0.0945 - 0.2795

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M8 X 0.75 6e (External)

* Permisable values for thread Class 6e

# Description Value (mm) Value (Inch)
es Allowance 0.056 (Ref) 0.0022 (Ref)
d Major Diameter 7.804 - 7.944 0.3072 - 0.3128
d2 Pitch Diameter 7.357 - 7.457 0.2896 - 0.2936
R Root Radius 0.094 (Min) 0.0037 (Min)
C Root Truncation 0.094 - 0.208 0.0037 - 0.0082
LE Normal Length of Engagement 2.4 - 7.1 0.0945 - 0.2795

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M8 X 0.75 6g (External)

* Permisable values for thread Class 6g

# Description Value (mm) Value (Inch)
es Allowance 0.022 (Ref) 0.0009 (Ref)
d Major Diameter 7.838 - 7.978 0.3086 - 0.3141
d2 Pitch Diameter 7.391 - 7.491 0.291 - 0.2949
R Root Radius 0.094 (Min) 0.0037 (Min)
C Root Truncation 0.094 - 0.208 0.0037 - 0.0082
LE Normal Length of Engagement 2.4 - 7.1 0.0945 - 0.2795

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M8 X 0.75 6h (External)

* Permisable values for thread Class 6h

# Description Value (mm) Value (Inch)
es Allowance 0 (Ref) 0 (Ref)
d Major Diameter 7.86 - 8 0.3094 - 0.315
d2 Pitch Diameter 7.413 - 7.513 0.2919 - 0.2958
R Root Radius 0.094 (Min) 0.0037 (Min)
C Root Truncation 0.094 - 0.208 0.0037 - 0.0082
LE Normal Length of Engagement 2.4 - 7.1 0.0945 - 0.2795

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M8 X 0.75 5g4g (External)

* Permisable values for thread Class 5g4g

# Description Value (mm) Value (Inch)
es Allowance 0.022 (Ref) 0.0009 (Ref)
d Major Diameter 7.888 - 7.978 0.3106 - 0.3141
d2 Pitch Diameter 7.411 - 7.491 0.2918 - 0.2949
R Root Radius 0.094 (Min) 0.0037 (Min)
C Root Truncation 0.094 - 0.196 0.0037 - 0.0077
LE Normal Length of Engagement 2.4 - 7.1 0.0945 - 0.2795

* Back to Thread Class Selection

M8 X 0.75 5h4h (External)

* Permisable values for thread Class 5h4h

# Description Value (mm) Value (Inch)
es Allowance 0 (Ref) 0 (Ref)
d Major Diameter 7.91 - 8 0.3114 - 0.315
d2 Pitch Diameter 7.433 - 7.513 0.2926 - 0.2958
R Root Radius 0.094 (Min) 0.0037 (Min)
C Root Truncation 0.094 - 0.196 0.0037 - 0.0077
LE Normal Length of Engagement 2.4 - 7.1 0.0945 - 0.2795

* Back to Thread Class Selection

M8 X 0.75 5g6g (External)

* Permisable values for thread Class 5g6g

# Description Value (mm) Value (Inch)
es Allowance 0.022 (Ref) 0.0009 (Ref)
d Major Diameter 7.838 - 7.978 0.3086 - 0.3141
d2 Pitch Diameter 7.411 - 7.491 0.2918 - 0.2949
R Root Radius 0.094 (Min) 0.0037 (Min)
C Root Truncation 0.094 - 0.196 0.0037 - 0.0077
LE Normal Length of Engagement 2.4 - 7.1 0.0945 - 0.2795

* Back to Thread Class Selection

M8 X 0.75 7g6g (External)

* Permisable values for thread Class 7g6g

# Description Value (mm) Value (Inch)
es Allowance 0.022 (Ref) 0.0009 (Ref)
d Major Diameter 7.838 - 7.978 0.3086 - 0.3141
d2 Pitch Diameter 7.366 - 7.491 0.29 - 0.2949
R Root Radius 0.094 (Min) 0.0037 (Min)
C Root Truncation 0.094 - 0.223 0.0037 - 0.0088
LE Normal Length of Engagement 2.4 - 7.1 0.0945 - 0.2795

* Back to Thread Class Selection

M8 X 0.75 7h6h (External)

* Permisable values for thread Class 7h6h

# Description Value (mm) Value (Inch)
es Allowance 0 (Ref) 0 (Ref)
d Major Diameter 7.86 - 8 0.3094 - 0.315
d2 Pitch Diameter 7.388 - 7.513 0.2909 - 0.2958
R Root Radius 0.094 (Min) 0.0037 (Min)
C Root Truncation 0.094 - 0.223 0.0037 - 0.0088
LE Normal Length of Engagement 2.4 - 7.1 0.0945 - 0.2795

* Back to Thread Class Selection

M8 X 0.75 7e6e (External)

* Permisable values for thread Class 7e6e

# Description Value (mm) Value (Inch)
es Allowance 0.056 (Ref) 0.0022 (Ref)
d Major Diameter 7.804 - 7.944 0.3072 - 0.3128
d2 Pitch Diameter 7.332 - 7.457 0.2887 - 0.2936
R Root Radius 0.094 (Min) 0.0037 (Min)
C Root Truncation 0.094 - 0.223 0.0037 - 0.0088
LE Normal Length of Engagement 2.4 - 7.1 0.0945 - 0.2795

* Back to Thread Class Selection

M8 X 0.75 4H (Internal)

* Permisable values for thread Class 4H

# Description Value (mm) Value (Inch)
EL Allowance 0 (Ref) 0 (Ref)
D1 Minor Diameter 7.188 - 7.306 0.283 - 0.2876
D2 Pitch Diameter 7.513 - 7.598 0.2958 - 0.2991
D Major Diameter 8 (Min) 0.315 (Min)
LE Normal Length of Engagement 2.4 - 7.1 0.0945 - 0.2795

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M8 X 0.75 5H (Internal)

* Permisable values for thread Class 5H

# Description Value (mm) Value (Inch)
EL Allowance 0 (Ref) 0 (Ref)
D1 Minor Diameter 7.188 - 7.338 0.283 - 0.2889
D2 Pitch Diameter 7.513 - 7.619 0.2958 - 0.3
D Major Diameter 8 (Min) 0.315 (Min)
LE Normal Length of Engagement 2.4 - 7.1 0.0945 - 0.2795

* Back to Thread Class Selection

M8 X 0.75 5G (Internal)

* Permisable values for thread Class 5G

# Description Value (mm) Value (Inch)
EL Allowance 0.022 (Ref) 0.0009 (Ref)
D1 Minor Diameter 7.21 - 7.36 0.2839 - 0.2898
D2 Pitch Diameter 7.535 - 7.641 0.2967 - 0.3008
D Major Diameter 8 (Min) 0.315 (Min)
LE Normal Length of Engagement 2.4 - 7.1 0.0945 - 0.2795

* Back to Thread Class Selection

M8 X 0.75 6H (Internal)

* Permisable values for thread Class 6H

# Description Value (mm) Value (Inch)
EL Allowance 0 (Ref) 0 (Ref)
D1 Minor Diameter 7.188 - 7.378 0.283 - 0.2905
D2 Pitch Diameter 7.513 - 7.645 0.2958 - 0.301
D Major Diameter 8 (Min) 0.315 (Min)
LE Normal Length of Engagement 2.4 - 7.1 0.0945 - 0.2795

* Back to Thread Class Selection

M8 X 0.75 6G (Internal)

* Permisable values for thread Class 6G

# Description Value (mm) Value (Inch)
EL Allowance 0.022 (Ref) 0.0009 (Ref)
D1 Minor Diameter 7.21 - 7.4 0.2839 - 0.2913
D2 Pitch Diameter 7.535 - 7.667 0.2967 - 0.3019
D Major Diameter 8 (Min) 0.315 (Min)
LE Normal Length of Engagement 2.4 - 7.1 0.0945 - 0.2795

* Back to Thread Class Selection

M8 X 0.75 7H (Internal)

* Permisable values for thread Class 7H

# Description Value (mm) Value (Inch)
EL Allowance 0 (Ref) 0 (Ref)
D1 Minor Diameter 7.188 - 7.424 0.283 - 0.2923
D2 Pitch Diameter 7.513 - 7.683 0.2958 - 0.3025
D Major Diameter 8 (Min) 0.315 (Min)
LE Normal Length of Engagement 2.4 - 7.1 0.0945 - 0.2795

* Back to Thread Class Selection

M8 X 0.75 7G (Internal)

* Permisable values for thread Class 7G

# Description Value (mm) Value (Inch)
EL Allowance 0.022 (Ref) 0.0009 (Ref)
D1 Minor Diameter 7.21 - 7.446 0.2839 - 0.2931
D2 Pitch Diameter 7.535 - 7.705 0.2967 - 0.3033
D Major Diameter 8 (Min) 0.315 (Min)
LE Normal Length of Engagement 2.4 - 7.1 0.0945 - 0.2795

* Back to Thread Class Selection

Tap Drill Sizes for M8 X 0.75

  • If not specified, assume a thread depth of 75%.
  • You can learn more about thread depth in tapping here.
  • To get the tap drill size in other depths, use our Tap Drill Size Calculator .
Thread Depth Tap Drill Size (Inch) Tap Drill Size (mm)
55% 0.294 7.46
60% 0.292 7.42
65% 0.290 7.37
70% 0.288 7.32
75% 0.286 7.27
80% 0.284 7.22
85% 0.282 7.17

Over Wire Measurements for M8 X 0.75


* OverWire is a measuring method to obatin the pitch diameter of threads. It is mostly used when a manufacturer does not have a Go/Nogo gauge for a thread. You can learn more about it here

mm Inch
Permissible Wire Diameter Range 0.379 - 0.758 0.0149 - 0.0298
Ideal Wire Diameter 0.433 0.017
Possible Wires
From Standard Sets		 * 0.404
* 0.433
* 0.462
* 0.52
* 0.577
* 0.722
 * 0.016
* 0.018
* 0.0193
* 0.0206
* 0.0214
* 0.0222
* 0.0241
* 0.0262
* 0.0289

Once you knoe your wire diameter, you need to find out what is the premissable Measurement for your pitch diameter (Depending on the class). Use our Over Wire Calculator to find out!


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