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Plugs Performance

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.

The Principle of Lee Plug Performance – How the Lee Plug Works

The Lee Plug solves the problem of leakage in drilled passageways – absolutely – without using O-rings, threads or adhesives.

Here's how it works:

  1. Insert the Plug into the reamed passageway.
  2. Drive in the tapered pin until it's flush with the plug.
  3. Controlled expansion causes the lands and grooves on the O.D. of the plug to "bite" into the surrounding material, forming a reliable, leak-tight seal for both liquids and gases.

Lee Plug illustration


Lee Plugs are manufactured to exacting tolerances. Every process is precisely controlled. Critical dimensions are 100% checked and others are statistically checked. All plugs and pins are 100% visually inspected. In addition, every lot of Lee Pins and Plugs is production acceptance tested. A representative sample of the mating pin or plug are performance tested to a Lee Company process specification for installation, leakage, pin retention, proof pressure and thermal stability. Two certificates of performance (one for the pin lot and one for the plug lot) accompany every shipment of Lee Plugs.