M14 X 1.25 - Basic Thread Dimensions

Property mm Inch
Nominal Diameter 14 0.5512
Pitch (Distance) 1.25 0.0492
Pitch Diameter 13.188 0.5192
Minor Diameter 12.647 0.4979
Thread Height 0.677 0.0267
Addendum 0.406 0.016
Crest (External)
Root (Internal)		 0.156 0.0061
Tap Drill Size
(75% depth)		 12.78 0.503
Lead Angle
(Single Start)		 1.73°
Thread Family Metric Fine Pitch (MF)
Relevant Standards ISO 68-1, ISO 9651-1, ISO 965-2, ISO 261,DIN 13
Equivalent Inch Thread9/16 - 20 20-UN

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

Table of Content

M14 X 1.25 Possible Thread Classes

External Threads

Choose tolerance class: 4g, 4h, 6e, 6g, 6h, 8e, 8g, 5g4g, 5h4h, 5g6g, 7g6g, 7h6h, 7e6e, 9e8e, 9g8g

Metric ISO External Thread - Tolerance sketch

Internal Threads

Choose tolerance class: 4H, 5H, 5G, 6H, 6G, 7H, 7G, 8G

Metric ISO Internal Thread - Tolerance sketch

M14 X 1.25 4g (External)

* Permisable values for thread Class 4g

# Description Value (mm) Value (Inch)
es Allowance 0.028 (Ref) 0.0011 (Ref)
d Major Diameter 13.84 - 13.972 0.5449 - 0.5501
d2 Pitch Diameter 13.075 - 13.16 0.5148 - 0.5181
R Root Radius 0.156 (Min) 0.0061 (Min)
C Root Truncation 0.156 - 0.293 0.0061 - 0.0115
LE Normal Length of Engagement 4.5 - 13 0.1772 - 0.5118

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M14 X 1.25 4h (External)

* Permisable values for thread Class 4h

# Description Value (mm) Value (Inch)
es Allowance 0 (Ref) 0 (Ref)
d Major Diameter 13.868 - 14 0.546 - 0.5512
d2 Pitch Diameter 13.103 - 13.188 0.5159 - 0.5192
R Root Radius 0.156 (Min) 0.0061 (Min)
C Root Truncation 0.156 - 0.293 0.0061 - 0.0115
LE Normal Length of Engagement 4.5 - 13 0.1772 - 0.5118

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M14 X 1.25 6e (External)

* Permisable values for thread Class 6e

# Description Value (mm) Value (Inch)
es Allowance 0.063 (Ref) 0.0025 (Ref)
d Major Diameter 13.725 - 13.937 0.5404 - 0.5487
d2 Pitch Diameter 12.993 - 13.125 0.5115 - 0.5167
R Root Radius 0.156 (Min) 0.0061 (Min)
C Root Truncation 0.156 - 0.325 0.0061 - 0.0128
LE Normal Length of Engagement 4.5 - 13 0.1772 - 0.5118

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M14 X 1.25 6g (External)

* Permisable values for thread Class 6g

# Description Value (mm) Value (Inch)
es Allowance 0.028 (Ref) 0.0011 (Ref)
d Major Diameter 13.76 - 13.972 0.5417 - 0.5501
d2 Pitch Diameter 13.028 - 13.16 0.5129 - 0.5181
R Root Radius 0.156 (Min) 0.0061 (Min)
C Root Truncation 0.156 - 0.325 0.0061 - 0.0128
LE Normal Length of Engagement 4.5 - 13 0.1772 - 0.5118

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M14 X 1.25 6h (External)

* Permisable values for thread Class 6h

# Description Value (mm) Value (Inch)
es Allowance 0 (Ref) 0 (Ref)
d Major Diameter 13.788 - 14 0.5428 - 0.5512
d2 Pitch Diameter 13.056 - 13.188 0.514 - 0.5192
R Root Radius 0.156 (Min) 0.0061 (Min)
C Root Truncation 0.156 - 0.325 0.0061 - 0.0128
LE Normal Length of Engagement 4.5 - 13 0.1772 - 0.5118

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M14 X 1.25 8e (External)

* Permisable values for thread Class 8e

# Description Value (mm) Value (Inch)
es Allowance 0.063 (Ref) 0.0025 (Ref)
d Major Diameter 13.602 - 13.937 0.5355 - 0.5487
d2 Pitch Diameter 12.913 - 13.125 0.5084 - 0.5167
R Root Radius 0.156 (Min) 0.0061 (Min)
C Root Truncation 0.156 - 0.374 0.0061 - 0.0147
LE Normal Length of Engagement 4.5 - 13 0.1772 - 0.5118

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M14 X 1.25 8g (External)

* Permisable values for thread Class 8g

# Description Value (mm) Value (Inch)
es Allowance 0.028 (Ref) 0.0011 (Ref)
d Major Diameter 13.637 - 13.972 0.5369 - 0.5501
d2 Pitch Diameter 12.948 - 13.16 0.5098 - 0.5181
R Root Radius 0.156 (Min) 0.0061 (Min)
C Root Truncation 0.156 - 0.374 0.0061 - 0.0147
LE Normal Length of Engagement 4.5 - 13 0.1772 - 0.5118

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M14 X 1.25 5g4g (External)

* Permisable values for thread Class 5g4g

# Description Value (mm) Value (Inch)
es Allowance 0.028 (Ref) 0.0011 (Ref)
d Major Diameter 13.84 - 13.972 0.5449 - 0.5501
d2 Pitch Diameter 13.054 - 13.16 0.5139 - 0.5181
R Root Radius 0.156 (Min) 0.0061 (Min)
C Root Truncation 0.156 - 0.308 0.0061 - 0.0121
LE Normal Length of Engagement 4.5 - 13 0.1772 - 0.5118

* Back to Thread Class Selection

M14 X 1.25 5h4h (External)

* Permisable values for thread Class 5h4h

# Description Value (mm) Value (Inch)
es Allowance 0 (Ref) 0 (Ref)
d Major Diameter 13.868 - 14 0.546 - 0.5512
d2 Pitch Diameter 13.082 - 13.188 0.515 - 0.5192
R Root Radius 0.156 (Min) 0.0061 (Min)
C Root Truncation 0.156 - 0.308 0.0061 - 0.0121
LE Normal Length of Engagement 4.5 - 13 0.1772 - 0.5118

* Back to Thread Class Selection

M14 X 1.25 5g6g (External)

* Permisable values for thread Class 5g6g

# Description Value (mm) Value (Inch)
es Allowance 0.028 (Ref) 0.0011 (Ref)
d Major Diameter 13.76 - 13.972 0.5417 - 0.5501
d2 Pitch Diameter 13.054 - 13.16 0.5139 - 0.5181
R Root Radius 0.156 (Min) 0.0061 (Min)
C Root Truncation 0.156 - 0.308 0.0061 - 0.0121
LE Normal Length of Engagement 4.5 - 13 0.1772 - 0.5118

* Back to Thread Class Selection

M14 X 1.25 7g6g (External)

* Permisable values for thread Class 7g6g

# Description Value (mm) Value (Inch)
es Allowance 0.028 (Ref) 0.0011 (Ref)
d Major Diameter 13.76 - 13.972 0.5417 - 0.5501
d2 Pitch Diameter 12.99 - 13.16 0.5114 - 0.5181
R Root Radius 0.156 (Min) 0.0061 (Min)
C Root Truncation 0.156 - 0.349 0.0061 - 0.0137
LE Normal Length of Engagement 4.5 - 13 0.1772 - 0.5118

* Back to Thread Class Selection

M14 X 1.25 7h6h (External)

* Permisable values for thread Class 7h6h

# Description Value (mm) Value (Inch)
es Allowance 0 (Ref) 0 (Ref)
d Major Diameter 13.788 - 14 0.5428 - 0.5512
d2 Pitch Diameter 13.018 - 13.188 0.5125 - 0.5192
R Root Radius 0.156 (Min) 0.0061 (Min)
C Root Truncation 0.156 - 0.349 0.0061 - 0.0137
LE Normal Length of Engagement 4.5 - 13 0.1772 - 0.5118

* Back to Thread Class Selection

M14 X 1.25 7e6e (External)

* Permisable values for thread Class 7e6e

# Description Value (mm) Value (Inch)
es Allowance 0.063 (Ref) 0.0025 (Ref)
d Major Diameter 13.725 - 13.937 0.5404 - 0.5487
d2 Pitch Diameter 12.955 - 13.125 0.51 - 0.5167
R Root Radius 0.156 (Min) 0.0061 (Min)
C Root Truncation 0.156 - 0.349 0.0061 - 0.0137
LE Normal Length of Engagement 4.5 - 13 0.1772 - 0.5118

* Back to Thread Class Selection

M14 X 1.25 9e8e (External)

* Permisable values for thread Class 9e8e

# Description Value (mm) Value (Inch)
es Allowance 0.063 (Ref) 0.0025 (Ref)
d Major Diameter 13.602 - 13.937 0.5355 - 0.5487
d2 Pitch Diameter 12.86 - 13.125 0.5063 - 0.5167
R Root Radius 0.156 (Min) 0.0061 (Min)
C Root Truncation 0.156 - 0.402 0.0061 - 0.0158
LE Normal Length of Engagement 4.5 - 13 0.1772 - 0.5118

* Back to Thread Class Selection

M14 X 1.25 9g8g (External)

* Permisable values for thread Class 9g8g

# Description Value (mm) Value (Inch)
es Allowance 0.028 (Ref) 0.0011 (Ref)
d Major Diameter 13.637 - 13.972 0.5369 - 0.5501
d2 Pitch Diameter 12.895 - 13.16 0.5077 - 0.5181
R Root Radius 0.156 (Min) 0.0061 (Min)
C Root Truncation 0.156 - 0.402 0.0061 - 0.0158
LE Normal Length of Engagement 4.5 - 13 0.1772 - 0.5118

* Back to Thread Class Selection

M14 X 1.25 4H (Internal)

* Permisable values for thread Class 4H

# Description Value (mm) Value (Inch)
EL Allowance 0 (Ref) 0 (Ref)
D1 Minor Diameter 12.647 - 12.817 0.4979 - 0.5046
D2 Pitch Diameter 13.188 - 13.3 0.5192 - 0.5236
D Major Diameter 14 (Min) 0.5512 (Min)
LE Normal Length of Engagement 4.5 - 13 0.1772 - 0.5118

* Back to Thread Class Selection

M14 X 1.25 5H (Internal)

* Permisable values for thread Class 5H

# Description Value (mm) Value (Inch)
EL Allowance 0 (Ref) 0 (Ref)
D1 Minor Diameter 12.647 - 12.859 0.4979 - 0.5063
D2 Pitch Diameter 13.188 - 13.328 0.5192 - 0.5247
D Major Diameter 14 (Min) 0.5512 (Min)
LE Normal Length of Engagement 4.5 - 13 0.1772 - 0.5118

* Back to Thread Class Selection

M14 X 1.25 5G (Internal)

* Permisable values for thread Class 5G

# Description Value (mm) Value (Inch)
EL Allowance 0.028 (Ref) 0.0011 (Ref)
D1 Minor Diameter 12.675 - 12.887 0.499 - 0.5074
D2 Pitch Diameter 13.216 - 13.356 0.5203 - 0.5258
D Major Diameter 14 (Min) 0.5512 (Min)
LE Normal Length of Engagement 4.5 - 13 0.1772 - 0.5118

* Back to Thread Class Selection

M14 X 1.25 6H (Internal)

* Permisable values for thread Class 6H

# Description Value (mm) Value (Inch)
EL Allowance 0 (Ref) 0 (Ref)
D1 Minor Diameter 12.647 - 12.912 0.4979 - 0.5083
D2 Pitch Diameter 13.188 - 13.368 0.5192 - 0.5263
D Major Diameter 14 (Min) 0.5512 (Min)
LE Normal Length of Engagement 4.5 - 13 0.1772 - 0.5118

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M14 X 1.25 6G (Internal)

* Permisable values for thread Class 6G

# Description Value (mm) Value (Inch)
EL Allowance 0.028 (Ref) 0.0011 (Ref)
D1 Minor Diameter 12.675 - 12.94 0.499 - 0.5094
D2 Pitch Diameter 13.216 - 13.396 0.5203 - 0.5274
D Major Diameter 14 (Min) 0.5512 (Min)
LE Normal Length of Engagement 4.5 - 13 0.1772 - 0.5118

* Back to Thread Class Selection

M14 X 1.25 7H (Internal)

* Permisable values for thread Class 7H

# Description Value (mm) Value (Inch)
EL Allowance 0 (Ref) 0 (Ref)
D1 Minor Diameter 12.647 - 12.982 0.4979 - 0.5111
D2 Pitch Diameter 13.188 - 13.412 0.5192 - 0.528
D Major Diameter 14 (Min) 0.5512 (Min)
LE Normal Length of Engagement 4.5 - 13 0.1772 - 0.5118

* Back to Thread Class Selection

M14 X 1.25 7G (Internal)

* Permisable values for thread Class 7G

# Description Value (mm) Value (Inch)
EL Allowance 0.028 (Ref) 0.0011 (Ref)
D1 Minor Diameter 12.675 - 13.01 0.499 - 0.5122
D2 Pitch Diameter 13.216 - 13.44 0.5203 - 0.5291
D Major Diameter 14 (Min) 0.5512 (Min)
LE Normal Length of Engagement 4.5 - 13 0.1772 - 0.5118

* Back to Thread Class Selection

M14 X 1.25 8G (Internal)

* Permisable values for thread Class 8G

# Description Value (mm) Value (Inch)
EL Allowance 0.028 (Ref) 0.0011 (Ref)
D1 Minor Diameter 12.675 - 13.1 0.499 - 0.5157
D2 Pitch Diameter 13.216 - 13.496 0.5203 - 0.5313
D Major Diameter 14 (Min) 0.5512 (Min)
LE Normal Length of Engagement 4.5 - 13 0.1772 - 0.5118

* Back to Thread Class Selection

Tap Drill Sizes for M14 X 1.25

  • 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% 0.516 13.11
60% 0.513 13.03
65% 0.510 12.94
70% 0.506 12.86
75% 0.503 12.78
80% 0.500 12.70
85% 0.497 12.62

Over Wire Measurements for M14 X 1.25


* 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 0.631 - 1.263 0.0249 - 0.0497
Ideal Wire Diameter 0.722 0.0284
Possible Wires
From Standard Sets		 * 0.722
* 0.866
* 1.01
* 1.155
 * 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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