Close Menu


Browse Plugs
Plugs for Oil and Gas

Expansion Plugs for Extreme Environments and Extreme Requirements

The Lee Company has produced expansion plugs since 1948, initially for the aircraft industry. Oil and gas became our second market shortly after that. Machines intended for downhole operations have unexpected commonalities with the aerospace industry. They must function in constrained environments and under extreme temperature, pressure, and vibration. Any failures can turn into unplanned downtime that costs millions of dollars a minute.

Unlike other designs that rely on threads, O-rings, or sealants, the Lee Plug® forms a leak-tight metal-to-metal seal using the principle of controlled expansion. We continued to innovate, meeting the unique challenges that inform the design of downhole oil tools and created new products from new materials to perform under extreme pressure.

Our lineup of plugs now features NACE-compliant designs that withstand extreme temperatures and pressures. We’ve also created removable and reusable plugs rated for pressures of up to 56,000 psi. Each new shipment of plugs is manufactured under a benchmark quality system and has exacting requirements for acceptance to ensure performance for a product that serves a function as a single point of failure. As a result, we guarantee the best designs and the best quality products to serve the most demanding industry on the planet when failure isn’t an option.

Our standard product offering usually contains a plug the size and proof pressure that a customer needs. This includes evolved configurations of our original expansion plug with different material, installation, and retention options. With that said, we’re more than happy to create new designs on request. Each of our customers is unique – and they often need unique plugs. Over half of the work we perform at The Lee Company is customized to meet the needs of a specific application. So whether your solution is off-the-shelf or one-of-a-kind, you can rest assured knowing that Lee products always adhere to exacting standards for quality and performance.

Lee Plug® Expansion Plugs

The founding flagship product from The Lee Company works like this: the cylindrical plug body contains a tapered hole partway through. First, the body is inserted into a properly reamed hole. Then, a tapered pin is inserted into the plug itself, causing the plug to expand in a controlled manner. Lands and grooves on the side of the plug then bite into the sides of the hole, creating multiple metal-to-metal seals. See Installation Process Specification 203 (which applies to all Lee expansion plugs) for more information.

Lee Plugs are manufactured to exacting tolerances. Every process is precisely controlled. Each lot of pins and plugs undergoes rigorous inspection and acceptance testing, which ensures performance when any failure could be catastrophic.

Standard Lee Plugs are available in multiple grades of aluminum, stainless steel, and Monel, plus titanium and MP35N. They can be purchased in diameters from 0.093 to 0.656 of an inch or metric sizes from 2.5 to 8.0 mm.

Lee R.F.O.® (Radial Force Only) Plugs

Lee R.F.O. Plugs are designed to seal holes in thin walls. These plugs are intended to be easily removable and do not require a support shoulder. In addition, the installation system ensures that no downward pressure is applied to the product.

Lee R.F.O. Plugs are available in aluminum and can be found in standard diameters ranging from 0.156 to 0.875 of an inch.

Lee QIP® (Quick Installation Plug) Plugs

The Lee QIP was developed to provide a more straightforward method of handling and installing the smallest plug sizes. This is accomplished by pre-installing the pin into the plug. Despite their smaller size, these plugs experience no loss of strength, with proof pressures up to 12,000 psi.

The Lee QIP is available in aluminum and is offered in four standard sizes: 0.093, 0.125, 0.156, and 0.187 inch diameters.

Lee A.F.O.® (Axial Force Only) Plugs

Unlike other plugs in our product family, A.F.O. Plugs are both removable and reusable due to their threaded design, allowing technicians easy access to sealed passageways. Despite this, the A.F.O. Plug still seals up to 56,000 psi. Each plug features a floating seal that self-aligns, allowing for threaded holes that aren’t concentric with the through-hole. Lastly, the A.F.O. designation means no radial force is applied during installation, making this component suitable for thinner-walled housings. See Installation Process Specification P1013 (which applies to all A.F.O. Plugs) for more information.

A.F.O. Plugs are made from either stainless steel or MP35N and are available in standard diameters from 0.190 to 0.625 of an inch.

Lee Dual Sealing A.F.O Plug

The Dual Sealing A.F.O. Plug comes with all the strength and ease-of-use of our regular A.F.O. Plugs, but with added safety features for use in hydraulic systems. Incorporating an O-ring allows users to vent gas out of a side port or safely release trapped high-pressure gas. This enables the Dual Sealing A.F.O. Plug to be used for “fill and drain” applications. In addition, a newer higher pressure version of this product is available with backup rings rated to seal up to 15,000 psi when partially open. See our Installation Process Specification for more information.

The Dual Sealing A.F.O. Plug is available in stainless steel and NACE-compliant MP35N. It is sold at a standard diameter of 0.750 of an inch.

Lee Cross Port Plugs

Lee Cross Port Plugs are a plugging solution specifically engineered to seal cross port passageways. This configuration is a variant of the original Lee Plug® that set industry standards over 65 years ago. A smooth wall design combined with the field-proven controlled expansion principle creates a permanent, leak-proof seal without the need for O-rings or sealants. Installation is simple and reliable, and the plug requires no maintenance once installed.

Lee Cross Port Plugs are ideal for isolating sections of a fluidic manifold. They are also used to plug deep passageways that are difficult to access with conventional sealing methods.

Lee Cross Port Plugs are constructed from 6Al-4V Titanium. They have been qualified for proof pressures over 20,000 psi and at temperatures up to 400°F. Configurations are available in 0.250, 0.281, and 0.343 inch diameters.

Support & Resources

Support & Resources from a Team that Speaks Your Language

Partner with The Lee Company and get much more than just a supplier of top-quality fluid control products. Our reliable technical support team is available every step of the way to help you find solutions, maximize productivity, and drive efficiency across your operations. Check out these resources tailored to the oil and gas industry to learn more.