What are sealing fasteners and when should you use them? 15 October 2021

In this article, US-based ZAGO Manufacturing Co, a manufacturer of speciality sealing solutions, explains what are sealing fasteners, as well as the applications they should be used in.

Sealing fasteners are highly specialised, high-tech fasteners that include sealing screws, sealing nuts, sealing bolts, and sealing washers. Unlike ordinary fasteners, sealing fasteners are configured with a rubber O-ring (or a rubber element) that when squeezed, permanently seal out contaminants such as oil, water, gas, saltwater, precipitation, moisture, dust, chemicals, from entering and damaging equipment while preventing contaminants from leaking into the environment. 

Sealing fasteners are engineered with a custom groove under the head of the screw or the face of the nut that when combined with a rubber O-ring (rubber element) and tightened, squeezes outwardly to form a 360 degree leak-proof hermetic seal. Once the screw is torqued, the O-ring will not break or crack, and metal-to-metal contact prolongs the life of the O-ring, which is not compromised under pressure. 

Sealing fasteners for all seasons

Sealing fasteners are designed to withstand harsh weather and extreme temperatures, such as when unmanned underwater vehicles survey the icy cold depths of the ocean floor to unmanned automotive vehicles operating in the extreme heat of the desert. They are vibration and pressure resistant and outperform ordinary fasteners in highly pressurised environments, including pneumatic pumps used in medical ventilators and pressure valves in industrial machinery.

Made of corrosion resistant metals, such as stainless steel and steel alloys, titanium, brass and monel, sealing fasteners are perfect for sealing indoor and outdoor equipment with confidence. They are reusable and may be unscrewed and retightened multiple times (i.e, routine battery changes).

Impervious to alcohol and other disinfectants, they are also a safe choice for sealing and wiping down invasive and non-invasive medical instruments and equipment (i.e surgical robots and kidney dialysis machines) and may be engineered with FDA-grade O-rings.

When to use sealing fasteners

Sealing fasteners are ideal for use when high asset machinery or sensitive equipment needs an air tight, hermetic seal to ensure protection from possible exposure to oil, gases, liquids, chemicals, dust, dirt, moisture, saltwater, or other contaminants. They are also used to withstand extreme pressure, temperature and/or weather conditions; as well as prevent the seepage of pollutants leaking into the environment.

ZAGO sealing fasteners are used in countless industries to seal all sorts of fixtures, components and equipment including robots and co-bots; electric vehicle charging units; aircraft engines and motors; drones and droneports; sonar systems; data centres; sensors; wind turbines and solar panels; rechargeable batteries; satellites; circuit boards; automated machinery; 3D cameras / LiDAR technology; commercial lighting; HVAC systems; and conveyor belts.

ZAGO sealing fasteners are made in the USA and ‘Buy American Act’ compliant.  ZAGO manufactures military grade sealing screws and O-rings that meet MS3212/MS3213/NASM 82496 and pressure tested to 1,500psi and NEMA-ready solutions for electrical enclosures. Parts are DFARS, REACH, RoHS, and DEKRA compliant.


Claire Aldridge Deputy Editor t: +44 (0) 1727 743 889

Having spent a decade in the fastener industry experiencing every facet – from steel mills, fastener manufacturers, wholesalers, distributors, as well as machinery builders and plating + coating companies, Claire has developed an in-depth knowledge of all things fasteners.

Alongside visiting numerous companies, exhibitions and conferences around the world, Claire has also interviewed high profile figures – focusing on key topics impacting the sector and making sure readers stay up to date with the latest developments within the industry.