Hillman Fasteners 47870 Lag Screws 3-1/2 X 5/16 in 25 Pack

Product Description

The HILLMAN FASTENERS 47870 is a 25-pack of Power Pro Bronze Ceramic Construction Lag Screws measuring 3-1/2 inches long by 5/16 inches in diameter. These fasteners feature a Type 17 cut point for clean entry into wood and a star drive head with coarse serrated threads for high-retention pull-through resistance. The bronze ceramic coating is tested to withstand 1500 hours of salt spray exposure, making these lags suitable for treated lumber, exterior framing, and corrosive environments. Licensed contractors, carpenters, and deck builders install these as a primary structural fastener where code-compliant corrosion resistance is required.

These lag screws are designed for structural wood-to-wood and wood-to-framing applications in residential and light commercial construction. Common install scenarios include deck framing connections, ledger board attachment, post anchoring, and heavy timber joinery. The coarse serrated thread pattern bites aggressively into dimensional lumber and engineered wood products. The star drive recess reduces cam-out during high-torque driving, which is particularly useful when driving lags into dense or pressure-treated stock.

Key Features

• Bronze ceramic coating rated for 1500-hour salt spray resistance for use with treated lumber
• Type 17 cut point self-starts in wood without a pilot hole in many applications
• Star drive head reduces cam-out and improves torque transfer
• Coarse serrated threads provide high pull-out resistance in structural connections
• Lifetime warranty included
• Sold in a 25-count box for jobsite-ready quantities

Compatibility

Designed as a structural construction lag screw for use in wood framing, deck construction, and exterior applications requiring corrosion-resistant fasteners compatible with pressure-treated lumber.

Installation Notes

Lag screws of this type are typically installed by carpenters, framers, and deck contractors using a star-bit impact driver or heavy-duty drill. A pilot hole is recommended in hardwoods or near board edges to prevent splitting. Consult applicable building codes, including IRC or IBC structural fastening requirements, for minimum embedment depth and spacing. Always verify fastener compatibility with the specific preservative treatment used in pressure-treated lumber before installation.