MIL-F-19700 Non-Magnetic Fasteners — Screw Threaded
MIL-F-19700 non-magnetic fasteners are specialized components described by MIL-F-19700A(SH). The specification outlines the characteristics of non-magnetic screw-threaded fasteners and related items that otherwise remain dimensionally in conformance with recognized military and industrial hardware standards. It operates as a supplemental specification for shipboard equipment sensitive to magnetic signatures, including mine countermeasure vessels and advanced sonar systems.
At a Glance
MIL-F-19700 Non-Magnetic Fasteners Overview
MIL-F-19700A describes the stringent characteristics of non-magnetic screw-threaded fasteners and related items that remain dimensionally in conformance with the recognized Federal Specification fasteners and industrial standards normally used for that part shape. For example, a hex bolt manufactured under this specification still matches its usual head, thread, and dimensional standard, but features added magnetic-property requirements layered on top to meet strict military criteria.
The specification's stated intent is highly explicit: it is meant to supplement, not supersede, the specifications normally used for the acquisition of threaded fasteners and related items. In field practice, this means a fastener drawing or purchase order will call out both its normal governing standard (such as an MS, NAS, or federal specification) and MIL-F-19700 revision A, with the latter adding the necessary non-magnetic material and testing requirements.
- The "(SH)" designator identifies Naval Sea Systems Command (Ships) as the specification's custodian, reflecting its critical origin in shipboard equipment where magnetic signature control is a matter of safety and mission success.
- Typical Naval Sea Systems Command fasteners include applications driving mine countermeasure vessels, degaussing systems, and equipment situated near sensitive magnetic or sonar instrumentation. In these environments, standard ferrous or magnetically-susceptible alloys could catastrophically interfere with function or increase vessel detectability.
Magnetic Permeability Testing
Because even inherently non-magnetic alloys can develop slight magnetic permeability during cold working, heading, or threading processes, MIL-F-19700 enforces strict permeability limits. Finished components must be subjected to magnetic permeability testing using specialized indicator tools (often per ASTM A342) to confirm the finished part remains below the specified magnetic threshold. Official guidelines and amendments for this testing process are continuously updated and stored in the Defense Logistics Agency (DLA) ASSIST portal.
Typical Non-Magnetic Material Options
MIL-F-19700 doesn't invent new fastener geometries — it adds a non-magnetic material requirement to an existing part standard. Common qualifying alloys include:
How MIL-F-19700 Is Typically Called Out
| Drawing Element | Role |
|---|---|
| Base Fastener Standard | Defines geometry, thread, head style (e.g. an MS or NAS bolt drawing) |
| MIL-F-19700 | Adds non-magnetic material and verification requirement |
| Magnetic Permeability Test | Confirms the finished part meets the specified non-magnetic threshold |
MIL-F-19700 is a supplemental specification — it's always paired with a fastener's normal governing document (such as an MS, NAS, or federal spec) rather than called out on its own. If you're sourcing non-magnetic hardware, specify both documents together on the purchase order or drawing.
Frequently Asked Questions
Does MIL-F-19700 replace the normal fastener spec?
No. It's explicitly written to supplement, not supersede, the specification normally used to acquire that fastener. Both documents are cited together on the procurement forms.
Why would a fastener need to be non-magnetic?
Certain naval platforms and equipment — mine countermeasure vessels, degaussing systems, sonar housings, and instrumentation sensitive to stray magnetic fields — require hardware that won't interfere with magnetic sensing or increase the vessel's magnetic signature.
What materials typically satisfy this requirement?
300-series austenitic stainless steel, nickel-copper alloy (Monel), brass and other copper-base alloys, titanium alloys, and aluminum alloys are all commonly used non-magnetic fastener materials — the specific choice depends entirely on the strength, corrosion resistance, and cost tradeoffs of the application.
Need Non-Magnetic Fasteners to MIL-F-19700?
Ananka Fasteners supplies non-magnetic hardware qualified to MIL-F-19700 alongside the applicable base fastener standard, with full material traceability.
Prefer email? sales@anankafasteners.com
