Getting into the groove 13 June 2023

The groove is the concave space located beneath the head of the screw or bolt and above the threads on the nut. It has a specific geometry that holds sealing rings or elastomers securely in place as the fastener is tightened. APM Hexseal is able to offer customisable sealing solutions to prevent contamination or leakages from either side of an enclosed space.

A well-engineered groove is critical to the ability of the fastener’s sealing ring to compress properly upon tightening, allowing an airtight, leak-proof barrier to form between the groove and the mating surface. In industrial applications, sealing hardware is essential for securely fastening components within a system – while simultaneously blocking contaminants from entering or exiting the sealed space.

APM Hexseal has decades of design and manufacturing experience to provide intelligently designed sealing solutions for a variety of mission critical and sensitive applications.

APM Hexseal’s screws, bolts, and other fasteners, are designed with built-in grooves that allow sealing elements to fit snugly and precisely under the fastener head. For instance, Seelnuts® contain a custom groove that enables the moulding of the elastomer directly into the threads, providing a superior and long-lasting seal. The design helps create a tight seal that confines the contents of operations while preventing external contaminants or debris from entering. Making sure the integrity of the fastener remains fully intact during the fabrication process is essential for achieving reliable sealing and fastening performance from the hardware.

High-tech sealing components are also available by request with FDA approved silicone to best support equipment used in sensitive applications, such as medical and pharmaceutical applications. With APM’s products with hardware’s integrity is maintained by incorporating the groove into the actual manufacturing process using cold forming techniques.

Selecting the right fastener with the appropriate groove geometry is essential to the hardware’s ability to seal properly. The exact parameters of a fastener’s groove will depend on multiple factors, such as the screw size and the panel cut-out. APM can customise virtually any aspect to the fastener or sealing element including the fastener material, as well as the sealing ring material. They can both be moulded from a wide range of elastomers allowing the choice of a material based on the specific conditions the fastener will encounter in applications. The colour of the elastomer can also be customised and the fasteners can be made to include various locking features, including self-locking pallets, strips and patches.

When choosing or designing sealing hardware for a specific application, there are several factors that should be considered to make sure the final product performs as intended. To form a proper seal, the elastomeric sealing element of the fastener must be able to deform by being compressed or stretched in various ways. The diameter, depth, and width, of a fastener’s groove will determine the sealing ring’s ability to be compressed properly against the mating surface to provide an adequate seal. Because of this, proper groove design plays a major role in the overall sealing performance of the hardware.

The exact features of a groove will depend on the overall size and style of the fastener, as well as the characteristics of the mounting panel that will be used. One of the most important design considerations is making sure the groove can be sized appropriately for the application without causing damage to the screw’s integrity.

A common mistake in fastener design is to allow the undercut to penetrate too deeply into the shank, causing the head of the fastener to break off when drilled into a surface. The engineers at APM Hexseal possess the expertise to prevent these types of failures, creating custom sealing hardware with expertly designed grooves that can ensure success in each application.

APM’s reusable self-sealing fasteners can block or contain liquids, lubricants, gases, and dust, making them perfect for protecting and confining sensitive materials and equipment. The fastener’s tight seal prevents contaminants from seeping into or out of the sealed environment through small gaps between the screw and the mating surface.

APM is ISO 9001:2015 certified and complies with a variety of other industry standards, including Dodd-Frank, REACH and RoHS.
Becca England Assistant Editor t: +44 (0) 1727 615 413

Becca is the latest member to join our team and is eager to get stuck into the world of fasteners. She brings an enthusiastic and fresh outlook on what we do editorially and will be leading our social media activity – including sourcing material, editing articles and posting online.