M64x4 Thread Specs
Standard: ISO 261 (ISO Metric Fine)
This reference guide outlines the technical dimensions and tapping parameters for the standard M64x4 metric thread.
Part of the ISO Metric Fine series defined by ISO 261, the thread features a nominal diameter of 64 mm and a pitch of 4 mm.
For machining or fabrication, the recommended tap drill size is 60 mm (for 75% thread depth) or 60.25 mm (for 65% thread depth).
Dimensional Specifications (mm)
Nominal Diameter
64 mm
Pitch
4 mm
Threads per mm
0.25
Major Diameter
64 mm
Pitch Diameter (d₂)
61.402 mm
Minor Diameter (d₁) Ext
59.67 mm
Minor Diameter (D₁) Int
60.247 mm
Thread Height
3.464 mm
Root Radius
0.577 mm
Drilling & Strength Specs
Tap Drill (75%)
60 mm
Tap Drill (65%)
60.25 mm
Stress Area
2850.78 mm²
Stress Diameter
59.093 mm
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Frequently Asked Questions
What is the tap drill size for a M64x4 thread?
For standard thread engagement (approx. 75%), the recommended tap drill size for M64x4 is 60 mm. For a slightly looser 65% thread engagement, a 60.25 mm drill bit is recommended.
What is the pitch of a M64x4 thread?
The thread pitch for a standard M64x4 thread is 4 mm, which equates to approximately 0.25 threads per millimeter.
What are the major and pitch diameters for M64x4?
The nominal major diameter of M64x4 is 64 mm. The calculated pitch diameter (d₂) is 61.402 mm per the ISO 68-1/ISO 261 standards.