M52 Thread Specs
Standard: ISO 261 (ISO Metric Coarse)
This reference guide outlines the technical dimensions and tapping parameters for the standard M52 metric thread.
Part of the ISO Metric Coarse series defined by ISO 261, the thread features a nominal diameter of 52 mm and a pitch of 5 mm.
For machining or fabrication, the recommended tap drill size is 47 mm (for 75% thread depth) or 47.31 mm (for 65% thread depth).
Dimensional Specifications (mm)
Nominal Diameter
52 mm
Pitch
5 mm
Threads per mm
0.2
Major Diameter
52 mm
Pitch Diameter (d₂)
48.752 mm
Minor Diameter (d₁) Ext
46.587 mm
Minor Diameter (D₁) Int
47.309 mm
Thread Height
4.33 mm
Root Radius
0.722 mm
Drilling & Strength Specs
Tap Drill (75%)
47 mm
Tap Drill (65%)
47.31 mm
Stress Area
1757.83 mm²
Stress Diameter
45.866 mm
Recommended Tightening Torque
| Property Class | Dry (Nm) | Lubricated (Nm) |
|---|---|---|
| Class 8.8 | 10000 | 7500 |
| Class 10.9 | 14700 | 11025 |
| Class 12.9 | 17640 | 13230 |
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Frequently Asked Questions
What is the tap drill size for a M52 thread?
For standard thread engagement (approx. 75%), the recommended tap drill size for M52 is 47 mm. For a slightly looser 65% thread engagement, a 47.31 mm drill bit is recommended.
What is the pitch of a M52 thread?
The thread pitch for a standard M52 thread is 5 mm, which equates to approximately 0.2 threads per millimeter.
What are the major and pitch diameters for M52?
The nominal major diameter of M52 is 52 mm. The calculated pitch diameter (d₂) is 48.752 mm per the ISO 68-1/ISO 261 standards.