MAN4MACHINEMJ2
Aerospace / High-Fatigue
Dimensionally an M thread at the pitch diameter -- same 60 degree flank, same pitch-diameter formula -- but the root is cut to a controlled minimum radius (rather than M's unspecified, often flat-truncated root) so the thread can survive repeated fatigue cycling. Used across aerospace and other high-fatigue fastening. Pitch-diameter and tolerance math is identical to M; the radius is a manufacturing and inspection requirement this database records but does not turn into a different basic diameter.
- Standard
- ISO 5855 / MIL-S-8879
- Flank angle
- 60° included
- Series
- Coarse pitch (default) -- assumed when a designation states no pitch
- Pitch
- 0.40 mm
Thread profile
A 60 degree included flank angle, with a controlled root radius rather than a flat truncation -- the fatigue-resistant detail this diagram's rounded root stands in for.
Basic major 2.000 mm, pitch diameter 1.740 mm, minor diameter 1.567 mm -- theoretical dimensions at zero allowance, before any tolerance class is applied.
MJ coarse sizes
| Designation | Pitch | Major Ø | Pitch Ø | Minor Ø |
|---|---|---|---|---|
| MJ1.6 | 0.35 mm | 1.60 mm | 1.373 mm | 1.221 mm |
| MJ2 | 0.40 mm | 2.00 mm | 1.740 mm | 1.567 mm |
| MJ2.5 | 0.45 mm | 2.50 mm | 2.208 mm | 2.013 mm |
| MJ3 | 0.50 mm | 3.00 mm | 2.675 mm | 2.459 mm |
| MJ3.5 | 0.60 mm | 3.50 mm | 3.110 mm | 2.850 mm |
| MJ4 | 0.70 mm | 4.00 mm | 3.545 mm | 3.242 mm |
| MJ5 | 0.80 mm | 5.00 mm | 4.480 mm | 4.134 mm |
| MJ6 | 1.00 mm | 6.00 mm | 5.350 mm | 4.917 mm |
| MJ8 | 1.25 mm | 8.00 mm | 7.188 mm | 6.647 mm |
| MJ10 | 1.50 mm | 10.00 mm | 9.026 mm | 8.376 mm |
| MJ12 | 1.75 mm | 12.00 mm | 10.863 mm | 10.106 mm |
| MJ14 | 2.00 mm | 14.00 mm | 12.701 mm | 11.835 mm |
| MJ16 | 2.00 mm | 16.00 mm | 14.701 mm | 13.835 mm |
| MJ18 | 2.50 mm | 18.00 mm | 16.376 mm | 15.294 mm |
| MJ20 | 2.50 mm | 20.00 mm | 18.376 mm | 17.294 mm |
| MJ22 | 2.50 mm | 22.00 mm | 20.376 mm | 19.294 mm |
| MJ24 | 3.00 mm | 24.00 mm | 22.051 mm | 20.752 mm |
| MJ27 | 3.00 mm | 27.00 mm | 25.051 mm | 23.752 mm |
| MJ30 | 3.50 mm | 30.00 mm | 27.727 mm | 26.211 mm |
| MJ33 | 3.50 mm | 33.00 mm | 30.727 mm | 29.211 mm |
| MJ36 | 4.00 mm | 36.00 mm | 33.402 mm | 31.670 mm |
Designation calculator
Try “M12x1.5-6g”, “M8” (coarse pitch assumed), “MJ6-4h6h”, or “Tr20x4-8H”. Add “-LH” for a left-hand thread.
Calculated live
Basic dimensions
- Major diameter
- 2.000 mm
- Pitch diameter
- 1.740 mm
- Minor diameter
- 1.567 mm
Tap drill · 75% thread
- Tap drill
- 1.70 mm (1.675 mm calculated)
- Clearance drill (normal)
- 2.80 mm (2.800 mm calculated)
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