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Automotive castings and manifolds are often complex, with numerous channels and passages that must be precisely connected to function properly. To achieve this, a process called “cross-drilling” is often required, where holes are drilled through the outer shell and internal channels of the casting. These cross-holes must then be sealed, which is why The Lee Company developed engineered expansion plugs for the automotive market. The Lee Betaplug® was designed to seal cross-holes in metal or plastic housings using a tapered plug and installation hole design, while the DL Series Plug* is ideal for sealing cross-holes in aluminum housings with a straight hole and shoulder design.
Lee Betaplug® expansion plugs operate without the need for threads, sealants, or O-rings. These pre-assembled, tapered plugs seal cross-holes using controlled expansion. The lands and grooves on the plug’s outer diameter bite into the housing wall during installation, creating a leak-tight seal and ensuring retention. This single-assembly design reduces costs, making the component cost-effective for mass production.
The tapered design of the Lee Betaplug® eliminates the need for tight manufacturing tolerances, which is ideal for high-volume applications. The matching tapers of the Betaplug and its installation hole create a perfect fit, eliminating the need for additional expansion. Since the size of the tapered pin precisely controls the Betaplug’s expansion, the amount of expansion and any resulting boss stress is completely predictable. This means that installation is repeatable – the same size plug will create the same stress, which is ideal for brittle materials or thin wall conditions.
The DL Series Plug is a single-piece, stainless-steel expansion plug specifically designed to seal holes in aluminum housings for the automotive market. DL Series Plugs seal straight cylindrical bores and sit on a chamfered installation shoulder. These expansion plugs are designed to be as shallow as possible in order to reduce space and manifold weight.
For this expansion plug, Lee developed the Drive Locking® technology which is purposely designed to facilitate reliable automated installation and verification processes, allowing customers to reduce scrap and labor costs while improving the reliability of their production processes. Visual indication of a proper installation is valuable for both low and high volume production as it adds a level of reliability and accountability to your manufacturing process.
*Patent Pending
Partner with The Lee Company and get much more than just a supplier of top-quality fluid control products. Find solutions, maximize productivity, and drive efficiency across your operations using our literature, case studies, and videos. Check out these resources for automotive manufacturers to learn more.
Always verify flow calculations by experiment.
*There are many parameters to consider when determining V-Factor. Click here for more information.
