M64 Thread Specs
Standard: ISO 261 (ISO Metric Coarse)
This reference guide outlines the technical dimensions and tapping parameters for the standard M64 metric thread.
Part of the ISO Metric Coarse series defined by ISO 261, the thread features a nominal diameter of 64 mm and a pitch of 6 mm.
For machining or fabrication, the recommended tap drill size is 58 mm (for 75% thread depth) or 58.37 mm (for 65% thread depth).
Dimensional Specifications (mm)
Nominal Diameter
64 mm
Pitch
6 mm
Threads per mm
0.17
Major Diameter
64 mm
Pitch Diameter (d₂)
60.103 mm
Minor Diameter (d₁) Ext
57.505 mm
Minor Diameter (D₁) Int
58.371 mm
Thread Height
5.196 mm
Root Radius
0.866 mm
Drilling & Strength Specs
Tap Drill (75%)
58 mm
Tap Drill (65%)
58.37 mm
Stress Area
2675.97 mm²
Stress Diameter
56.639 mm
Recommended Tightening Torque
| Property Class | Dry (Nm) | Lubricated (Nm) |
|---|---|---|
| Class 8.8 | 18700 | 14025 |
| Class 10.9 | 27500 | 20625 |
| Class 12.9 | 33000 | 24750 |
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Frequently Asked Questions
What is the tap drill size for a M64 thread?
For standard thread engagement (approx. 75%), the recommended tap drill size for M64 is 58 mm. For a slightly looser 65% thread engagement, a 58.37 mm drill bit is recommended.
What is the pitch of a M64 thread?
The thread pitch for a standard M64 thread is 6 mm, which equates to approximately 0.17 threads per millimeter.
What are the major and pitch diameters for M64?
The nominal major diameter of M64 is 64 mm. The calculated pitch diameter (d₂) is 60.103 mm per the ISO 68-1/ISO 261 standards.