M22 Thread Specs
Standard: ISO 261 (ISO Metric Coarse)
This reference guide outlines the technical dimensions and tapping parameters for the standard M22 metric thread.
Part of the ISO Metric Coarse series defined by ISO 261, the thread features a nominal diameter of 22 mm and a pitch of 2.5 mm.
For machining or fabrication, the recommended tap drill size is 19.5 mm (for 75% thread depth) or 19.66 mm (for 65% thread depth).
Dimensional Specifications (mm)
Nominal Diameter
22 mm
Pitch
2.5 mm
Threads per mm
0.4
Major Diameter
22 mm
Pitch Diameter (d₂)
20.376 mm
Minor Diameter (d₁) Ext
19.294 mm
Minor Diameter (D₁) Int
19.655 mm
Thread Height
2.165 mm
Root Radius
0.361 mm
Drilling & Strength Specs
Tap Drill (75%)
19.5 mm
Tap Drill (65%)
19.66 mm
Stress Area
303.4 mm²
Stress Diameter
18.933 mm
Recommended Tightening Torque
| Property Class | Dry (Nm) | Lubricated (Nm) |
|---|---|---|
| Class 8.8 | 690 | 517.5 |
| Class 10.9 | 1015 | 761.3 |
| Class 12.9 | 1218 | 913.5 |
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Frequently Asked Questions
What is the tap drill size for a M22 thread?
For standard thread engagement (approx. 75%), the recommended tap drill size for M22 is 19.5 mm. For a slightly looser 65% thread engagement, a 19.66 mm drill bit is recommended.
What is the pitch of a M22 thread?
The thread pitch for a standard M22 thread is 2.5 mm, which equates to approximately 0.4 threads per millimeter.
What are the major and pitch diameters for M22?
The nominal major diameter of M22 is 22 mm. The calculated pitch diameter (d₂) is 20.376 mm per the ISO 68-1/ISO 261 standards.