Lee Expansion Plugs

Featured Product from Lee Co. (The)

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Lee Plug® expansion plugs seal fluid passages leak-tight, without the use of O-rings, threads, or sealants.

It is simply the most successful method of sealing drilled holes in critical applications. Well over 100 million Lee Plugs have been used on aircraft, missiles, spacecraft, and other sophisticated hydraulic systems that require a permanent leak-tight seal.

Learn how the Lee Plug works.

Available Designs

Lee Plug expansion plugs are available in three versions:

  • The original Lee Plug is available in short and long versions in a range of English sizes from 0.093" dia. to 0.656" dia., and in metric sizes from 2.5mm to 8.0mm. A variety of standard material combinations are available.
  • The High-Strength Lee Plug is specifically designed for high-pressure systems and has been optimized for use in high-strength/high-hardness materials, such as the precipitation hardenable steels titanium.
  • Lee Plug RFO® (Radial Force Only) The Lee Plug RFO is designed to seal holes in thin walls or fragile materials. Designed to be easily removable, the plug does not require a support shoulder and the installation system assures that no downward pressure is applied to the product.

Threaded Plugs        

In addition to our expansion plug family, Lee offers threaded A.F.O. and Dual Sealing A.F.O. plugs for higher pressures up to 56,000 psi. Both are offered in NACE Compliant versions to meet the special demands of the oil and gas industries.

  • A.F.O. (Axial Force Only)  Plugs provide a leak-tight, metal-to-metal seal in higher-pressure/high-temperature manifold applications. Designed to be both removable and reusable, the plugs feature a unique floating seal that self-aligns to prevent galling.
  • Dual Sealing A.F.O. (Axial Force Only) Plugs incorporate an O-ring for venting. Pressure can be vented out of a side port to remove air from a hydraulic system, or safely release trapped high pressure gas.