Selecting the right fastener specification is critical in defence and aerospace engineering. Whether you are sourcing NAS bolts, MS hardware or AS-series aerospace fasteners, each standard carries specific performance expectations, certification requirements and dimensional controls that directly affect the safety and reliability of your platform.
This guide breaks down the differences between NAS fasteners, MS fasteners and AS fasteners, helping engineers, procurement teams and programme managers make informed choices.
TL;DR
NAS fasteners offer the highest precision and fatigue performance for aerospace and defence systems, MS fasteners support legacy military platforms, and AS fasteners provide modernised specifications for new-build projects. Choosing the right standard depends on load requirements, environment, certification needs and platform compatibility.
Need Help Selecting the Right Specification?
JP Aero supplies fully certified NAS, MS and AS hardware with expert guidance for defence and aerospace programmes. Get in touch for technical support and dependable sourcing.
Why Fastener Standards Matter in Defence and Aerospace
Modern defence systems operate under extreme thermal, mechanical and environmental loads. The fastener products used across military aircraft, naval systems and weapons platforms must therefore meet standards far beyond those required in commercial engineering.
For this reason, NAS, MS and AS specifications remain the global benchmarks for precision bolts, screws, nuts and rivets used in high-risk applications. Each standard defines:
- Material and mechanical requirements
- Dimensional tolerances
- Surface finish and coatings
- Heat treatment processes
- Testing and traceability levels
Choosing the wrong specification can compromise structural integrity, introduce fatigue issues or lead to non-compliance with defence procurement frameworks.
Understanding NAS Fasteners
What Are NAS Fasteners?
NAS (National Aerospace Standards) represent some of the most rigorously controlled hardware available. Originally developed for critical aerospace and defence platforms, NAS hardware offers superior dimensional accuracy, fatigue performance and long-term durability.
NAS components include nas bolts, nuts, washers, high-strength aerospace bolts, precision nas screws, and specialist rivets.
Common series include:
- NAS624 – High-strength, corrosion-resistant bolts widely used in aircraft structures
- NAS6203 – Bearings and related hardware engineered for rotational loads
- NAS1306 – Tension and shear rivets for structural aerospace assemblies
These parts are not simply “high-spec” equivalents of commercial hardware — they are engineered for mission-critical use.
Why Choose NAS Fasteners for Defence?
Defence programmes select NAS components when the engineering demands:
- Exceptional fatigue resistance
- High tensile properties
- Tight dimensional tolerances
- Repeatable performance over decades
- Compatibility with titanium, aluminium and composite structures
NAS hardware is especially common in flight-critical locations on both crewed and unmanned aerospace platforms.
Because NAS parts must be produced by approved manufacturers operating under strict process controls, they also offer an unmatched level of consistency and full traceability, essential in defence procurement.
MS Fasteners: Legacy Military Standards Still Widely Used
What Are MS Fasteners?
MS (Military Standard) hardware is one of the longest-standing ranges of defence-approved components. While some MS specifications have been superseded by AS standards, many ms parts, ms screws, nuts and bolts remain active, particularly in legacy aircraft support and overhaul programmes.
MS fasteners are known for:
- Defined mechanical strength classes
- Controlled plating and corrosion-protection requirements
- Standardisation across NATO and allied supply chains
Their long service history means they appear extensively in defence documentation and drawings.
When Are MS Fasteners the Right Choice?
MS-spec hardware remains essential where:
- Platform drawings explicitly reference MS codes
- Interchangeability with legacy hardware is required
- Defence maintenance teams rely on established part families
- Cost-effective alternatives to NAS fasteners are acceptable
Although MS parts typically offer lower fatigue performance than NAS equivalents, they remain fully approved for many non-flight-critical military applications.
AS Fasteners: The Modern Evolution of MS Standards
What Are AS Fasteners?
AS (Aerospace Standards) hardware was introduced to modernise and consolidate many legacy MS specifications. Administered through SAE International, AS standards update the material, dimensional and testing criteria to align with current aerospace engineering requirements.
AS fasteners include:
- Bolts
- Nuts
- Washers
- Precision screws
- Inserts and structural hardware
AS parts also support digital documentation and modern quality-management frameworks, making them highly suitable for new-build defence systems.
Why Choose AS Fasteners?
AS-spec hardware is preferred when:
- You are designing new defence or aerospace systems
- Modern certification and documentation are required
- You want compatibility with advanced alloys and coatings
- You need predictable supply from approved manufacturers
For many procurement teams, AS hardware represents the “future-proof” standard.
How to Choose Between NAS, MS and AS Standards
Selecting the right specification depends on:
1. Platform Requirements
New aerospace systems often prefer AS standards; high-fatigue areas favour NAS; legacy fleets typically maintain MS documentation.
2. Mechanical and Environmental Conditions
For heat- or vibration-intensive applications, NAS bolts or high-strength stainless steel bolts are common choices.
3. Certification and Traceability Needs
NAS and AS parts usually offer enhanced inspection routes and more robust documentation packages.
4. Interchangeability
If drawings call for NAS624, NAS6203, NAS1306 or equivalent legacy MS parts, maintaining the original specification avoids compliance issues.
5. Material Compatibility
Fastener and structural materials must work together — e.g. titanium structures often pair with NAS products.
JP Aero supports defence engineers in selecting the right specification by analysing load requirements, materials, environmental exposure and lifecycle expectations.
Why Work with a Specialist Fastener Supplier?
Defence and aerospace programmes rely on suppliers who can provide:
- Certification to NAS, MS and AS standards
- Full traceability across every production step
- Approved materials (e.g. A286, titanium, Inconel, stainless steel)
- Reliable supply from audited manufacturers
- Technical support for specification selection
- Consistency across global sourcing programmes
JP Aero delivers compliant, fully certified hardware across a wide range of NAS bolts, AS fasteners, MS components and specialist aerospace products, supporting MRO, upgrades and new-build defence platforms.
Conclusion
NAS, MS and AS standards each play a distinct role in defence and aerospace fasteners procurement. Whether you are working on a new defence aircraft, a naval system, a surveillance platform or a land-based military programme, choosing the correct specification ensures safety, compliance and long-term reliability.
If you need guidance on selecting the right fastener series for your engineering requirements, JP Aero can help you identify the most appropriate solution with full certification and dependable supply.
Speak to Our Aerospace & Defence Fastener Experts
For NAS, MS or AS hardware — including nas bolts, stainless steel bolts, ms screws, nas screws and specialist aerospace fastener products — speak to the JP Aero team. We provide technical support, certified supply routes and trusted delivery for defence and aerospace programmes worldwide.