M100 Thread Specs
Standard: ISO 261 (ISO Metric Coarse)
This reference guide outlines the technical dimensions and tapping parameters for the standard M100 metric thread.
Part of the ISO Metric Coarse series defined by ISO 261, the thread features a nominal diameter of 100 mm and a pitch of 6 mm.
For machining or fabrication, the recommended tap drill size is 94 mm (for 75% thread depth) or 94.37 mm (for 65% thread depth).
Dimensional Specifications (mm)
Nominal Diameter
100 mm
Pitch
6 mm
Threads per mm
0.17
Major Diameter
100 mm
Pitch Diameter (d₂)
96.103 mm
Minor Diameter (d₁) Ext
93.505 mm
Minor Diameter (D₁) Int
94.371 mm
Thread Height
5.196 mm
Root Radius
0.866 mm
Drilling & Strength Specs
Tap Drill (75%)
94 mm
Tap Drill (65%)
94.37 mm
Stress Area
6994.64 mm²
Stress Diameter
92.639 mm
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Frequently Asked Questions
What is the tap drill size for a M100 thread?
For standard thread engagement (approx. 75%), the recommended tap drill size for M100 is 94 mm. For a slightly looser 65% thread engagement, a 94.37 mm drill bit is recommended.
What is the pitch of a M100 thread?
The thread pitch for a standard M100 thread is 6 mm, which equates to approximately 0.17 threads per millimeter.
What are the major and pitch diameters for M100?
The nominal major diameter of M100 is 100 mm. The calculated pitch diameter (d₂) is 96.103 mm per the ISO 68-1/ISO 261 standards.