MIL-DTL-25027 Self-Locking Nuts — 250°F, 450°F & 800°F
The specification for MIL-DTL-25027 self-locking nuts covered specialized fasteners designed for continuous service at 250°F, 450°F, and 800°F, depending on the base material. The document's final update, MIL-DTL-25027 revision H (15 August 1997), superseded the earlier MIL-N-25027G. The entire document was itself superseded on December 14, 1999, by NASM25027, which remains the active governing specification today.
At a Glance
MIL-DTL-25027 Self-Locking Nuts Overview
MIL-DTL-25027 was the direct successor to MIL-N-25027G, establishing rigorous performance criteria for high-temperature lock nuts. The standard rated these components for continuous service at 250°F, 450°F, or 800°F based entirely on the base material and locking element utilized. Copper-base and aluminum alloys with non-metallic inserts were strictly limited to 250°F, non-corrosion-resistant steel reached 450°F, and all-metal corrosion-resistant steel (CRES) configurations were certified up to 800°F.
The Department of Defense published the final issue, Revision H, on August 15, 1997. The entire specification was formally superseded on December 14, 1999, when the government adopted NASM25027 as the governing document. This action transferred the maintenance of these critical Federal Specification fasteners to the Aerospace Industries Association's NAS/Military (NASM) document family.
- Products originally qualified under MIL-DTL-25027 through certified government testing are legally considered qualified under the current NASM25027 standard without requiring retesting.
- Any new aerospace procurement or engineering design should cite NASM25027 directly rather than the obsolete military detail specification.
Qualification and Testing Requirements
Because self-locking nuts are utilized in flight-critical and high-vibration applications, the original military specification established rigorous testing protocols that have carried over to the modern NASM equivalent. Fasteners must pass extensive torque-out testing (verifying the locking element retains friction after multiple installation/removal cycles), vibration resistance testing, and high-temperature bake tests to ensure the locking mechanisms do not fail under dynamic operational stress. You can track the official cancellation notice and transition documents via the Defense Logistics Agency (DLA) portal.
Specification Lineage
| Document | Status |
|---|---|
| MIL-N-25027 (through Rev. G) | Superseded by MIL-DTL-25027 |
| MIL-DTL-25027 (Rev. H, 1997) | Superseded by NASM25027 |
| NASM25027 (1999–present) | Active, current governing document |
MIL-DTL-25027 is superseded. Current and future procurement should reference NASM25027, which covers the same high-temperature lock nut family under active maintenance by the Aerospace Industries Association. This page is retained for legacy drawing cross-reference only.
Frequently Asked Questions
Is MIL-DTL-25027 the same nut as NASM25027?
Functionally, yes — NASM25027 is the direct successor document and covers the exact same self-locking nut family, temperature classes, and material options. Products previously qualified under the military standard carry over as qualified under NASM25027.
Why do some drawings still cite the old specification?
Older engineering drawings and blueprints often retain the specification number that was in effect when they were originally released (like MIL-N-25027G or MIL-DTL-25027). For current procurement, buyers must cross-reference to NASM25027.
Need Self-Locking Nuts to NASM25027?
Ananka Fasteners manufactures current NASM25027 self-locking nuts with full material traceability and Mill Test Certification.
Prefer email? sales@anankafasteners.com
