M72 Thread Specs
Standard: ISO 261 (ISO Metric Coarse)
This reference guide outlines the technical dimensions and tapping parameters for the standard M72 metric thread.
Part of the ISO Metric Coarse series defined by ISO 261, the thread features a nominal diameter of 72 mm and a pitch of 6 mm.
For machining or fabrication, the recommended tap drill size is 66 mm (for 75% thread depth) or 66.37 mm (for 65% thread depth).
Dimensional Specifications (mm)
Nominal Diameter
72 mm
Pitch
6 mm
Threads per mm
0.17
Major Diameter
72 mm
Pitch Diameter (d₂)
68.103 mm
Minor Diameter (d₁) Ext
65.505 mm
Minor Diameter (D₁) Int
66.371 mm
Thread Height
5.196 mm
Root Radius
0.866 mm
Drilling & Strength Specs
Tap Drill (75%)
66 mm
Tap Drill (65%)
66.37 mm
Stress Area
3459.74 mm²
Stress Diameter
64.639 mm
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Frequently Asked Questions
What is the tap drill size for a M72 thread?
For standard thread engagement (approx. 75%), the recommended tap drill size for M72 is 66 mm. For a slightly looser 65% thread engagement, a 66.37 mm drill bit is recommended.
What is the pitch of a M72 thread?
The thread pitch for a standard M72 thread is 6 mm, which equates to approximately 0.17 threads per millimeter.
What are the major and pitch diameters for M72?
The nominal major diameter of M72 is 72 mm. The calculated pitch diameter (d₂) is 68.103 mm per the ISO 68-1/ISO 261 standards.