M56x4 Thread Specs
Standard: ISO 261 (ISO Metric Fine)
This reference guide outlines the technical dimensions and tapping parameters for the standard M56x4 metric thread.
Part of the ISO Metric Fine series defined by ISO 261, the thread features a nominal diameter of 56 mm and a pitch of 4 mm.
For machining or fabrication, the recommended tap drill size is 52 mm (for 75% thread depth) or 52.25 mm (for 65% thread depth).
Dimensional Specifications (mm)
Nominal Diameter
56 mm
Pitch
4 mm
Threads per mm
0.25
Major Diameter
56 mm
Pitch Diameter (d₂)
53.402 mm
Minor Diameter (d₁) Ext
51.67 mm
Minor Diameter (D₁) Int
52.247 mm
Thread Height
3.464 mm
Root Radius
0.577 mm
Drilling & Strength Specs
Tap Drill (75%)
52 mm
Tap Drill (65%)
52.25 mm
Stress Area
2143.96 mm²
Stress Diameter
51.093 mm
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Frequently Asked Questions
What is the tap drill size for a M56x4 thread?
For standard thread engagement (approx. 75%), the recommended tap drill size for M56x4 is 52 mm. For a slightly looser 65% thread engagement, a 52.25 mm drill bit is recommended.
What is the pitch of a M56x4 thread?
The thread pitch for a standard M56x4 thread is 4 mm, which equates to approximately 0.25 threads per millimeter.
What are the major and pitch diameters for M56x4?
The nominal major diameter of M56x4 is 56 mm. The calculated pitch diameter (d₂) is 53.402 mm per the ISO 68-1/ISO 261 standards.