Lag Screws
Lag Screws (Lag Bolts) – Heavy-Duty Fasteners for Structural Wood Connections
Lag screws, also known as lag bolts, are among the strongest fasteners available for wood-to-wood and wood-to-metal applications. Engineered for maximum holding power, these heavy-duty fasteners feature a hex head design that is installed using a wrench or socket, allowing for superior torque and clamping strength. Commonly used in construction, deck building, framing, and structural reinforcement, lag screws provide the durability and load capacity required for demanding projects.
Standard Hex Head Lag Screws
Standard hex head lag screws are the most widely used option for structural wood fastening. Designed with deep, coarse threads and a sharp point, they penetrate wood fibers effectively to create strong mechanical grip. Typically manufactured from carbon steel, these lag bolts are available in plain finish, zinc-plated, or hot-dip galvanized coatings. Zinc plating works well for interior use, while hot-dip galvanized finishes are ideal for pressure-treated lumber and outdoor environments.
Stainless Steel Lag Screws
For marine, coastal, or high-moisture environments, stainless steel lag screws provide superior corrosion resistance. Available in 18-8 stainless steel or 316 stainless steel, these fasteners resist rust and staining, making them ideal for docks, decks, fencing, and exterior structures exposed to harsh weather conditions.
Structural Wood Screws (Modern Lag Alternatives)
Structural wood screws are advanced alternatives to traditional lag bolts. Often featuring self-tapping threads and Torx® or star drive heads, these screws offer faster installation and may eliminate the need for pre-drilling. Many meet ICC code requirements for structural applications.
Silicon Bronze Lag Screws
Silicon bronze lag screws are commonly used in historic restorations and boatbuilding. They offer excellent corrosion resistance along with an attractive, classic finish.
Key Specifications
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Diameters: Typically 1/4" to 3/4"
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Lengths: 1" to 12"+
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Materials: Carbon steel, stainless steel, silicon bronze
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Finishes: Zinc, hot-dip galvanized, stainless
Selecting the right lag screw ensures long-term structural integrity, superior load performance, and reliable fastening in critical applications.