M4.5 - Basic Thread Dimensions

Property mm Inch
Nominal Diameter 4.5 0.1772
Pitch (Distance) 0.75 0.0295
Pitch Diameter 4.013 0.158
Minor Diameter 3.688 0.1452
Thread Height 0.406 0.016
Addendum 0.244 0.0096
Crest (External)
Root (Internal)
0.094 0.0037
Tap Drill Size
(75% depth)
3.77 0.148
Lead Angle
(Single Start)
3.4°
Thread Family Metric Coarse Pitch (MC)
Relevant Standards ISO 68-1, ISO 9651-1, ISO 965-2, ISO 261,DIN 13
Equivalent Inch Thread#10 - 32 32-UN

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

Table of Content


M4.5 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

M4.5 4g (External)

* Permisable values for thread Class 4g

# Description Value (mm) Value (Inch)
es Allowance 0.022 (Ref) 0.0009 (Ref)
d Major Diameter 4.388 - 4.478 0.1728 - 0.1763
d2 Pitch Diameter 3.935 - 3.991 0.1549 - 0.1571
R Root Radius 0.094 (Min) 0.0037 (Min)
C Root Truncation 0.094 - 0.179 0.0037 - 0.007
LE Normal Length of Engagement 2.2 - 6.7 0.0866 - 0.2638

* Back to Thread Class Selection


M4.5 4h (External)

* Permisable values for thread Class 4h

# Description Value (mm) Value (Inch)
es Allowance 0 (Ref) 0 (Ref)
d Major Diameter 4.41 - 4.5 0.1736 - 0.1772
d2 Pitch Diameter 3.957 - 4.013 0.1558 - 0.158
R Root Radius 0.094 (Min) 0.0037 (Min)
C Root Truncation 0.094 - 0.179 0.0037 - 0.007
LE Normal Length of Engagement 2.2 - 6.7 0.0866 - 0.2638

* Back to Thread Class Selection


M4.5 6e (External)

* Permisable values for thread Class 6e

# Description Value (mm) Value (Inch)
es Allowance 0.056 (Ref) 0.0022 (Ref)
d Major Diameter 4.304 - 4.444 0.1694 - 0.175
d2 Pitch Diameter 3.867 - 3.957 0.1522 - 0.1558
R Root Radius 0.094 (Min) 0.0037 (Min)
C Root Truncation 0.094 - 0.202 0.0037 - 0.008
LE Normal Length of Engagement 2.2 - 6.7 0.0866 - 0.2638

* Back to Thread Class Selection


M4.5 6g (External)

* Permisable values for thread Class 6g

# Description Value (mm) Value (Inch)
es Allowance 0.022 (Ref) 0.0009 (Ref)
d Major Diameter 4.338 - 4.478 0.1708 - 0.1763
d2 Pitch Diameter 3.901 - 3.991 0.1536 - 0.1571
R Root Radius 0.094 (Min) 0.0037 (Min)
C Root Truncation 0.094 - 0.202 0.0037 - 0.008
LE Normal Length of Engagement 2.2 - 6.7 0.0866 - 0.2638

* Back to Thread Class Selection


M4.5 6h (External)

* Permisable values for thread Class 6h

# Description Value (mm) Value (Inch)
es Allowance 0 (Ref) 0 (Ref)
d Major Diameter 4.36 - 4.5 0.1717 - 0.1772
d2 Pitch Diameter 3.923 - 4.013 0.1544 - 0.158
R Root Radius 0.094 (Min) 0.0037 (Min)
C Root Truncation 0.094 - 0.202 0.0037 - 0.008
LE Normal Length of Engagement 2.2 - 6.7 0.0866 - 0.2638

* Back to Thread Class Selection


M4.5 5g4g (External)

* Permisable values for thread Class 5g4g

# Description Value (mm) Value (Inch)
es Allowance 0.022 (Ref) 0.0009 (Ref)
d Major Diameter 4.388 - 4.478 0.1728 - 0.1763
d2 Pitch Diameter 3.92 - 3.991 0.1543 - 0.1571
R Root Radius 0.094 (Min) 0.0037 (Min)
C Root Truncation 0.094 - 0.19 0.0037 - 0.0075
LE Normal Length of Engagement 2.2 - 6.7 0.0866 - 0.2638

* Back to Thread Class Selection


M4.5 5h4h (External)

* Permisable values for thread Class 5h4h

# Description Value (mm) Value (Inch)
es Allowance 0 (Ref) 0 (Ref)
d Major Diameter 4.41 - 4.5 0.1736 - 0.1772
d2 Pitch Diameter 3.942 - 4.013 0.1552 - 0.158
R Root Radius 0.094 (Min) 0.0037 (Min)
C Root Truncation 0.094 - 0.19 0.0037 - 0.0075
LE Normal Length of Engagement 2.2 - 6.7 0.0866 - 0.2638

* Back to Thread Class Selection


M4.5 5g6g (External)

* Permisable values for thread Class 5g6g

# Description Value (mm) Value (Inch)
es Allowance 0.022 (Ref) 0.0009 (Ref)
d Major Diameter 4.338 - 4.478 0.1708 - 0.1763
d2 Pitch Diameter 3.92 - 3.991 0.1543 - 0.1571
R Root Radius 0.094 (Min) 0.0037 (Min)
C Root Truncation 0.094 - 0.19 0.0037 - 0.0075
LE Normal Length of Engagement 2.2 - 6.7 0.0866 - 0.2638

* Back to Thread Class Selection


M4.5 7g6g (External)

* Permisable values for thread Class 7g6g

# Description Value (mm) Value (Inch)
es Allowance 0.022 (Ref) 0.0009 (Ref)
d Major Diameter 4.338 - 4.478 0.1708 - 0.1763
d2 Pitch Diameter 3.879 - 3.991 0.1527 - 0.1571
R Root Radius 0.094 (Min) 0.0037 (Min)
C Root Truncation 0.094 - 0.215 0.0037 - 0.0085
LE Normal Length of Engagement 2.2 - 6.7 0.0866 - 0.2638

* Back to Thread Class Selection


M4.5 7h6h (External)

* Permisable values for thread Class 7h6h

# Description Value (mm) Value (Inch)
es Allowance 0 (Ref) 0 (Ref)
d Major Diameter 4.36 - 4.5 0.1717 - 0.1772
d2 Pitch Diameter 3.901 - 4.013 0.1536 - 0.158
R Root Radius 0.094 (Min) 0.0037 (Min)
C Root Truncation 0.094 - 0.215 0.0037 - 0.0085
LE Normal Length of Engagement 2.2 - 6.7 0.0866 - 0.2638

* Back to Thread Class Selection


M4.5 7e6e (External)

* Permisable values for thread Class 7e6e

# Description Value (mm) Value (Inch)
es Allowance 0.056 (Ref) 0.0022 (Ref)
d Major Diameter 4.304 - 4.444 0.1694 - 0.175
d2 Pitch Diameter 3.845 - 3.957 0.1514 - 0.1558
R Root Radius 0.094 (Min) 0.0037 (Min)
C Root Truncation 0.094 - 0.215 0.0037 - 0.0085
LE Normal Length of Engagement 2.2 - 6.7 0.0866 - 0.2638

* Back to Thread Class Selection


M4.5 4H (Internal)

* Permisable values for thread Class 4H

# Description Value (mm) Value (Inch)
EL Allowance 0 (Ref) 0 (Ref)
D1 Minor Diameter 3.688 - 3.806 0.1452 - 0.1498
D2 Pitch Diameter 4.013 - 4.088 0.158 - 0.1609
D Major Diameter 4.5 (Min) 0.1772 (Min)
LE Normal Length of Engagement 2.2 - 6.7 0.0866 - 0.2638

* Back to Thread Class Selection


M4.5 5H (Internal)

* Permisable values for thread Class 5H

# Description Value (mm) Value (Inch)
EL Allowance 0 (Ref) 0 (Ref)
D1 Minor Diameter 3.688 - 3.838 0.1452 - 0.1511
D2 Pitch Diameter 4.013 - 4.108 0.158 - 0.1617
D Major Diameter 4.5 (Min) 0.1772 (Min)
LE Normal Length of Engagement 2.2 - 6.7 0.0866 - 0.2638

* Back to Thread Class Selection


M4.5 5G (Internal)

* Permisable values for thread Class 5G

# Description Value (mm) Value (Inch)
EL Allowance 0.022 (Ref) 0.0009 (Ref)
D1 Minor Diameter 3.71 - 3.86 0.1461 - 0.152
D2 Pitch Diameter 4.035 - 4.13 0.1589 - 0.1626
D Major Diameter 4.5 (Min) 0.1772 (Min)
LE Normal Length of Engagement 2.2 - 6.7 0.0866 - 0.2638

* Back to Thread Class Selection


M4.5 6H (Internal)

* Permisable values for thread Class 6H

# Description Value (mm) Value (Inch)
EL Allowance 0 (Ref) 0 (Ref)
D1 Minor Diameter 3.688 - 3.878 0.1452 - 0.1527
D2 Pitch Diameter 4.013 - 4.131 0.158 - 0.1626
D Major Diameter 4.5 (Min) 0.1772 (Min)
LE Normal Length of Engagement 2.2 - 6.7 0.0866 - 0.2638

* Back to Thread Class Selection


M4.5 6G (Internal)

* Permisable values for thread Class 6G

# Description Value (mm) Value (Inch)
EL Allowance 0.022 (Ref) 0.0009 (Ref)
D1 Minor Diameter 3.71 - 3.9 0.1461 - 0.1535
D2 Pitch Diameter 4.035 - 4.153 0.1589 - 0.1635
D Major Diameter 4.5 (Min) 0.1772 (Min)
LE Normal Length of Engagement 2.2 - 6.7 0.0866 - 0.2638

* Back to Thread Class Selection


M4.5 7H (Internal)

* Permisable values for thread Class 7H

# Description Value (mm) Value (Inch)
EL Allowance 0 (Ref) 0 (Ref)
D1 Minor Diameter 3.688 - 3.924 0.1452 - 0.1545
D2 Pitch Diameter 4.013 - 4.163 0.158 - 0.1639
D Major Diameter 4.5 (Min) 0.1772 (Min)
LE Normal Length of Engagement 2.2 - 6.7 0.0866 - 0.2638

* Back to Thread Class Selection


M4.5 7G (Internal)

* Permisable values for thread Class 7G

# Description Value (mm) Value (Inch)
EL Allowance 0.022 (Ref) 0.0009 (Ref)
D1 Minor Diameter 3.71 - 3.946 0.1461 - 0.1554
D2 Pitch Diameter 4.035 - 4.185 0.1589 - 0.1648
D Major Diameter 4.5 (Min) 0.1772 (Min)
LE Normal Length of Engagement 2.2 - 6.7 0.0866 - 0.2638

* Back to Thread Class Selection


Tap Drill Sizes for M4.5

  • 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% 0.156 3.96
60% 0.154 3.92
65% 0.152 3.87
70% 0.150 3.82
75% 0.148 3.77
80% 0.146 3.72
85% 0.145 3.67

Over Wire Measurements for M4.5


* 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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