Hillman 10 Pack Expansion Nuts (1/4"-20 x 1") | Rubber Well Nuts with Steel Insert | Blind Hole Fasteners for Sealing Leakproof Mounting Automotive Marine Applications

Product Description Hillman expansion nuts, also known as well nuts, are designed to provide secure fastening in blind or closed-end hole applications where access to the backside is not available. These fasteners are commonly used in automotive, marine, and general repair projects where reliable internal anchoring and sealing are required. Each expansion nut features a neoprene rubber body with a threaded steel insert embedded at one end. When a bolt is inserted and tightened, the rubber body expands inside the hole, creating a firm grip against the surrounding material. This expansion helps stabilize the fastener while improving holding strength and reducing the risk of loosening over time. In addition to providing a secure hold, the expanding rubber creates a tight seal around the bolt hole. This helps prevent leaks from water, air, or debris, making these nuts suitable for applications where sealing performance is important. This dual functionality of fastening and sealing makes them a practical solution for a variety of installation scenarios. Designed with a standard 1/4"-20 coarse thread, these expansion nuts are compatible with commonly used bolts and threaded rods. Ideal for repair, maintenance, and installation tasks, they provide a dependable fastening solution in applications requiring both secure anchoring and leak resistance. From the Manufacturer An expansion or well nut consists of a flanged neoprene bushing with a threaded nut embedded in the non flanged end. It is used in blind bolt holes to fasten a piece and seal the bolt hole. The nut is inserted into the hole flange side up, as the bolt is screwed into the nut the rubber on the other side of the hole expands and seals the bolt hole.

• DESIGNED FOR BLIND HOLE FASTENING APPLICATIONS: Ideal for blind or closed-end holes, providing secure fastening for automotive, marine, and repair applications where back access is limited.
• EXPANDING RUBBER DESIGN FOR SECURE HOLD: Features a neoprene rubber body that expands when tightened, creating a firm grip and improving holding strength, reducing loosening in vibration-prone or dynamic applications.
• LEAKPROOF SEALING PERFORMANCE: Expands to seal around the bolt hole, preventing water, air, or debris from passing through, ideal for moisture resistance in outdoor and enclosed installations.
• 1/4"-20 COARSE THREAD COMPATIBILITY: Equipped with a steel insert featuring a standard 1/4"-20 coarse thread, ensuring compatibility with bolts and threaded rods for reliable fastening performance across various applications.
• TRUSTED HILLMAN FASTENING SOLUTIONS: Hillman hardware is engineered for quality, reliable performance, and easy use in construction, repair, and home improvement. Trusted by professionals and DIYers for consistent results in everyday projects.