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A guide to the standards and specifications for wire thread inserts

Posted by Advanex  |  

There are hundreds of relevant standards and specifications that govern how, why, and which wire thread inserts should be used.

The aerospace and automotive industries each have a set of specifications that apply to designs for each of their corresponding industries. These industries contain a number of safety-critical applications, where inaccuracies, design errors or faults can pose a threat to health and safety. In light of this, wire thread inserts require rigorous testing and standardisation to ensure performance and reliability.

In this article, we dive into the different wire thread insert specifications.

Why are there standards for wire thread inserts?

Aerospace applications operate on the precipice of precision engineering. Because of this, they call for components that can be pushed to the absolute limit and maintain full functionality and reliability. Standardisation ensures these factors, as well as the full interoperability of components from different manufacturers.

Wire thread insert standards provide aerospace and defence contractors with confidence in their ability to perform reliably in the long-term. They undergo rigorous torque, tension and vibration testing as well as comprehensive dimensional inspection and metallurgical analysis. As a result, engineers can have confidence in the fastening capabilities of the wire thread inserts whilst in the field.

What are the standards for wire thread inserts?

NAS and MA Standards

NAS (National Aerospace Standards) is a comprehensive set of wire thread insert standards of unified thread sizes. They ensure the interoperability and reliability of fastening solutions between aerospace components. Not only does this bring efficiency to the engineering process, but ensures a high standard of performance for these components. For metric thread sizes, the MA series of standards is used.

Unified Sizing

Specification Description
A-A-59156 A specification that describes tools for inserting and extracting wire thread inserts.
AS7245 A wire thread insert with a helical coil, a procurement specification.
AS7246 A wire thread insert with a helical coil, made using Inconel (corrosion and heat resistant alloy).
NAS1130 A tangless wire thread insert with a helical coil.
NASM122076-122275 A free running wire thread insert with a coarse thread.
NASM124651-124850 A free running fine thread wire thread insert.
NASM21209 A self locking wire thread insert, self locking in coarse and fine thread.
NASM33537 A wire thread insert in inch series, with standard assembly dims.
NASM8646 A procurement specification for the unified series.

Metric Sizing

Specification Description
NA0276 A tangless wire thread insert in free running and self-locking.
MA1565 Metric series of wire thread inserts, a procurement specification.
MA1567 Metric series of wire thread inserts with standard assembly dims.
MA3279 Uncoated wire thread inserts in free running.
MA3280 Dry film lubricated, free running wire thread inserts.
MA3281 Cadmium plated wire thread inserts in free running.
MA3329 Uncoated self-locking wire thread inserts in metric series.
MA3330 Dry film lubricated wire thread inserts in self-locking.
MA3331 Cadmium plated, self-locking wire thread inserts in metric.

AMS Standards

AMS (Aerospace Material Specifications) were established by the Society of Automotive Engineers (SAE). They focus on the material science tied to inserts, such as their compositions, tolerances and surface coating/plating. AMS wire thread insert specifications provide security of the quality and reliability of their material properties to be used in aerospace applications.

Platings and Coatings

Standards & Specification Description
AMS-QQ-P-416 Plating – Cadmium, electrodeposited.
AMS2410 Plating – Silver, Nickle Strike, High Bake
AMS2411 Plating – Silver for high temperature applications
AMS2412 Plating – Silver, Copper Strike, Low Bake
AMS-C-26074 Plating – Electroless Nickel
AMS2700 Passivation of CRES
AS5272 Lubricant – Solid Film, Heat Cured, Corrosion Inhibiting. Procurement Specification.

KATO® Inserts, made to match the standards.

KATO® Advanex wire thread inserts are fully compliant with NAS, MA and AMS standards with full traceability. We hold a commitment to reliability and operability, but take it a step further by providing industry leading performance and quality with each of our products.

KATO® Tanged solutions use high-integrity and wear-resistant threads that exceed the strength of most parent materials. Additionally, they are available in a wide range of size ranges and material compositions to suit any component in any environment.

KATO® Tangless products eliminate the risk of foreign object debris (FOD) in critical applications. With a bi-directional notch design and individual coil flexion, KATO® Tangless solutions save manufacturers considerable time and production costs without compromising on performance.

For pricing information or to get a quote for our products, contact a member of our team today.

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