ALNsbMJ MJ A286 Self-Locking Nuts (EN 3152)
The ALNsbMJ range is an Auto-Lok MJ-thread single-slotted prevailing-torque nut manufactured from A286 stainless steel and aligned with EN 3152. It delivers reusable all-metal locking (no nylon insert) for aerospace MJ internal threads.
Why MJ threads are specified in aerospace
The MJ thread form is the aerospace metric standard, known for a larger root radius that supports improved fatigue behavior. It is commonly specified with tighter internal tolerances such as 4H6H or 4H5H. If the drawing calls for an MJ internal thread, use an MJ nut and match it with an MJ external thread.
What you get with ALNsbMJ
- Reusable prevailing-torque locking (no polymer insert)
- Suitable when the drawing specifies MJ internal threads
- Reduced prevailing torque for smoother assembly and repeatable re-installation
ALNsbMJ part numbers (A286, EN 3152)
| Auto-Lok nut | Auto-Lok nut with silver plating finish | Thread |
|---|---|---|
| ALNsbMJ3x050A286 | ALNsbMJ3x050A286SP | MJ3 × 0,5 — 4H6H |
| ALNsbMJ4x070A286 | ALNsbMJ4x070A286SP | MJ4 × 0,7 — 4H6H |
| ALNsbMJ5x080A286 | ALNsbMJ5x080A286SP | MJ5 × 0,8 — 4H6H |
| ALNsbMJ6x100A286 | ALNsbMJ6x100A286SP | MJ6 × 1,0 — 4H5H |
| ALNsbMJ7x100A286 | ALNsbMJ7x100A286SP | MJ7 × 1,0 — 4H5H |
| ALNsbMJ8x100A286 | ALNsbMJ8x100A286SP | MJ8 × 1,0 — 4H5H |
| ALNsbMJ10x125A286 | ALNsbMJ10x125A286SP | MJ10 × 1,25 — 4H5H |
| ALNsbMJ12x125A286 | ALNsbMJ12x125A286SP | MJ12 × 1,25 — 4H5H |
Standard & acceptance criteria
DIN EN 3152:2005 specifies technical delivery conditions for self-locking nuts with MJ thread manufactured from FE-PA2601 (A286), silver-plated or uncoated.
It also defines qualification procedures and required quality-assurance documentation, with a strength class of 1100 MPa at room temperature and a maximum test temperature of 425 °C.
FAQ
Do you have MJ thread Auto-Lok nuts?
Yes. We supply MJ-thread prevailing-torque nuts for aerospace applications, including the EN 3152-aligned ALNsbMJ (A286) range. MJ is the aerospace metric standard and is typically specified with tighter internal tolerances (e.g. 4H6H / 4H5H).
When should I choose MJ instead of standard metric M?
Choose MJ when the drawing explicitly requires an MJ thread form or when fatigue behavior at the thread root is a key concern (common in aerospace). Always match MJ internal threads with MJ external threads.
Is prevailing torque the same as tightening torque?
No. Prevailing torque is the resistance of the locking feature. Tightening torque is the installation torque defined for the joint (size/grade/lubrication). Confirm the nut’s prevailing-torque range meets your spec (often referenced with ISO 2320 limits and methods).
Need help selecting the correct MJ nut?
Share your drawing requirements (thread, tolerance, finish, temperature) and we’ll help you shortlist the right part numbers.