--- title: Galling protection description: Galling is a very common problem experienced by customers using locking helical coil inserts. Typically galling occurs when the bolt passes through the locking coil and binds. image: https://blog.katoadvanex.com/hubfs/221015ADVANX0221-0%20(1).jpg --- [Skip to content](https://blog.katoadvanex.com/galling-protection#main) - [Products](https://www.katoadvanex.com/products/) - [![](https://www.katoadvanex.com/wp-content/uploads/2023/08/tanged-thumbnail.jpg) KATO® Tanged Inserts](https://www.katoadvanex.com/tanged-inserts/) - [![](https://www.katoadvanex.com/wp-content/uploads/2023/08/tangless-thumbnail.jpg) KATO Tangless® Inserts](https://www.katoadvanex.com/tangless-inserts/) - [![](https://www.katoadvanex.com/wp-content/uploads/2023/08/tooling-thumbnail.jpg) KATO® Tooling](https://www.katoadvanex.com/tooling/) - [See all products](https://www.katoadvanex.com/products/) - [Industries](https://www.katoadvanex.com/industries/) - [![](https://www.katoadvanex.com/wp-content/uploads/2023/04/Rectangle-197.png) Aerospace](https://www.katoadvanex.com/aerospace/) - [![](https://www.katoadvanex.com/wp-content/uploads/2023/04/Mask-group-min.webp) Automotive](https://www.katoadvanex.com/automotive/) - [![](https://www.katoadvanex.com/wp-content/uploads/2023/04/electronics-image-semiconductor-1.jpeg) Electronics](https://www.katoadvanex.com/electronics/) - [![](https://www.katoadvanex.com/wp-content/uploads/2023/04/advanex-industry-train.jpg) Rail](https://www.katoadvanex.com/railway/) - [Technology](https://www.katoadvanex.com/kato-technology/) - [Distributors](https://www.katoadvanex.com/distributors/) - [Resources](https://blog.katoadvanex.com/) - [Get Pricing](https://www.katoadvanex.com/contact-us/) [Get Pricing](https://www.katoadvanex.com/contact-us/) Article # Galling protection Posted by Advanex  |   13 April, 2023 Galling is a very common problem experienced by customers using locking helical coil inserts. Typically galling occurs when the bolt passes through the locking coil and binds. This is particularly evident with like materials. The result is that the insert is threaded out of the hole when the bolt is removed, or the insert is threaded deeper into the hole when the bolt is tightened. Less obvious, is the slight movement of the insert in the hole, which may be undetectable to the operators. The most common cause of galling is the use of dead soft bolts, e.g., 300 series stainless steel. CoilThread® inserts are made of cold-rolled 304 stainless steel wire (AS7245), work-hardened to a tensile strength above 200,000 psi and a hardness of Rc 43-50. In order to minimise galling heat-treated screws with a hardness of Rc 36-43 is strongly recommended. Locking CoilThread® inserts produce torques in accordance to MIL-I-8846 when they are used with heat-treated cadmium plated bolts. KATO recommends avoid the use of  300 series stainless bolts. Stainless steel requirements should use A286 aircraft quality screws. In applications where stainless steel screws are mandatory or when using heat-treated unplated bolts an anti-seize compound, e.g., molybdenum disulfide, must be used in order to minimise galling. Specifying CoilThread inserts with dry film lubricants or cadmium plating are other option available to the customer. [![KATO Brochure Discover the full KATO range for 2025. Get brochure](https://hubspot-no-cache-eu1-prod.s3.amazonaws.com/cta/default/27133590/6bb301de-9ed2-4f73-8634-8643efc3218d.png)](https://hubspot-cta-redirect-eu1-prod.s3.amazonaws.com/cta/redirect/27133590/6bb301de-9ed2-4f73-8634-8643efc3218d) ### Related Resources from Advanex - ### [![](https://blog.katoadvanex.com/hs-fs/hubfs/Red-dye-on-locking-Coilthread.jpg?width=352&name=Red-dye-on-locking-Coilthread.jpg) Article Red dye on locking Coilthread® inserts Unlocking the Red Dye Mystery: Red dye in locking inserts is simply for identification, without affecting the installation.. 16 March, 2023 More](https://blog.katoadvanex.com/red-dye-on-locking-coilthread-inserts) - ### [![](https://blog.katoadvanex.com/hs-fs/hubfs/torque%20fasteners.jpg?width=352&name=torque%20fasteners.jpg) Article What is positive locking and why is it vital to mechanical joint longevity? We define the concept of positive locking and highlight its importance in maintaining joint integrity. 25 November, 2024 More](https://blog.katoadvanex.com/what-is-positive-locking-and-why-is-it-vital-to-mechanical-joint-longevity) - ### [![](https://blog.katoadvanex.com/hs-fs/hubfs/coilthread-rebrands-as-kato.jpg?width=352&name=coilthread-rebrands-as-kato.jpg) Article CoilThread® announces rebranding to KATO® CoilThread® evolves into KATO®, honoring its founder and a century of excellence. Discover KATO®'s legacy in.. 20 July, 2023 More](https://blog.katoadvanex.com/coilthread-announces-rebranding-to-kato-by-advanex) - ### [![](https://blog.katoadvanex.com/hs-fs/hubfs/Insert-assembly-tensile-strength.jpg?width=352&name=Insert-assembly-tensile-strength.jpg) Article Insert assembly tensile strength Uncover the secrets behind tensile strength in bolted assemblies using CoilThread® inserts. Get the insights to engineer.. 06 April, 2023 More](https://blog.katoadvanex.com/insert-assembly-tensile-strength) - ### [![](https://blog.katoadvanex.com/hs-fs/hubfs/Shutterstock_1473498770%20(1).jpg?width=352&name=Shutterstock_1473498770%20(1).jpg) Article Galvanic corrosion resistance for mechanical joints Examining the methods of mitigating against galvanic corrosion and how wire thread inserts enhance the corrosion resistance.. 14 December, 2023 More](https://blog.katoadvanex.com/galvanic-corrosion-resistance-for-mechanical-joints) - ### [![](https://blog.katoadvanex.com/hs-fs/hubfs/aircraft%20galvanic.jpg?width=352&name=aircraft%20galvanic.jpg) Article Galvanic corrosion in aircraft - how to detect and prevent it 25 March, 2025 More](https://blog.katoadvanex.com/galvanic-corrosion-in-aircraft-how-to-detect-and-prevent-it) [View all](https://blog.katoadvanex.com) ### Decades of knowledge. Just try us. Got a question? Want to discuss your requirements? Get in touch with our expert team. [Get in touch](https://www.katoadvanex.com/contact-us/) ### Industries - [Aerospace](https://www.katoadvanex.com/aerospace/) - [Automotive](https://www.katoadvanex.com/automotive/) - [Electronics](https://www.katoadvanex.com/electronics/) - [Rail](https://www.katoadvanex.com/railway/) ### About us - [Our Industries](https://www.katoadvanex.com/industries/) - [Our Technology](https://www.katoadvanex.com/kato-technology/) - [Privacy Policy](https://www.katoadvanex.com/privacy-policy/) - [Data Protection Policy](https://www.katoadvanex.com/data-protection-policy/) ### Products - [Tanged Inserts](https://www.katoadvanex.com/tanged-inserts/) - [Tangless® Inserts](https://www.katoadvanex.com/tangless-inserts/) - [KATO® Tooling](https://www.katoadvanex.com/tooling/) All the latest news and information from KATO [Privacy policy](https://www.katoadvanex.com/privacy-policy/) #### Proud members of: ![IST](https://blog.katoadvanex.com/hubfs/ist.png) ![SMMT](https://blog.katoadvanex.com/hubfs/smmt.png) ![Nottingham Manufacturing Network](https://blog.katoadvanex.com/hubfs/nmn.png) © 2026 Advanex KATO® KATO® Tanged & Tangless® Wire Thread Inserts are manufactured by Advanex Worldwide [Website by Forge®](https://www.forge.uk/) ```json { "@context" : "https://schema.org", "@type" : "BlogPosting", "author" : { "@type" : "Person", "name" : "Advanex", "url" : "https://blog.katoadvanex.com/author/advanex" }, "dateModified" : "2023-11-01T17:36:54.208Z", "datePublished" : "2023-04-13T10:35:00.000Z", "headline" : "Galling protection", "image" : [ "https://blog.katoadvanex.com/hubfs/221015ADVANX0221-0%20(1).jpg" ], "mainEntityOfPage" : { "@id" : "https://blog.katoadvanex.com/galling-protection", "@type" : "WebPage" }, "publisher" : { "@type" : "Organization", "logo" : { "@type" : "ImageObject", "url" : "https://blog.katoadvanex.com/hubfs/kato-advanex-favicon.png" }, "name" : "Advanex Europe Limited" } } ```