M5 Thread Specs
Standard: ISO 261 (ISO Metric Coarse)
This reference guide outlines the technical dimensions and tapping parameters for the standard M5 metric thread.
Part of the ISO Metric Coarse series defined by ISO 261, the thread features a nominal diameter of 5 mm and a pitch of 0.8 mm.
For machining or fabrication, the recommended tap drill size is 4.2 mm (for 75% thread depth) or 4.25 mm (for 65% thread depth).
Dimensional Specifications (mm)
Nominal Diameter
5 mm
Pitch
0.8 mm
Threads per mm
1.25
Major Diameter
5 mm
Pitch Diameter (d₂)
4.48 mm
Minor Diameter (d₁) Ext
4.134 mm
Minor Diameter (D₁) Int
4.249 mm
Thread Height
0.693 mm
Root Radius
0.115 mm
Drilling & Strength Specs
Tap Drill (75%)
4.2 mm
Tap Drill (65%)
4.25 mm
Stress Area
14.18 mm²
Stress Diameter
4.019 mm
Recommended Tightening Torque
| Property Class | Dry (Nm) | Lubricated (Nm) |
|---|---|---|
| Class 8.8 | 7.5 | 5.6 |
| Class 10.9 | 11 | 8.3 |
| Class 12.9 | 13 | 9.8 |
Quick Unit Converter
mm
⇄
inch
Frequently Asked Questions
What is the tap drill size for a M5 thread?
For standard thread engagement (approx. 75%), the recommended tap drill size for M5 is 4.2 mm. For a slightly looser 65% thread engagement, a 4.25 mm drill bit is recommended.
What is the pitch of a M5 thread?
The thread pitch for a standard M5 thread is 0.8 mm, which equates to approximately 1.25 threads per millimeter.
What are the major and pitch diameters for M5?
The nominal major diameter of M5 is 5 mm. The calculated pitch diameter (d₂) is 4.48 mm per the ISO 68-1/ISO 261 standards.