5/16 x 1 1/4 Stainless Steel 18-8 Hex Lag Screw

Description

5/16 x 1 1/4 Stainless Steel (SS) 18-8 Hex Lag Screw is a high-quality, durable fastener that offers greater corrosion resistance than zinc or HDG alternatives, often used for marine and chemical-exposure wood fastening applications.

Also known as an “SS 18-8 hex lag bolt” or “stainless steel lag bolt,” hex lag screws have a flat bearing surface, a hexagonal head, and a fully threaded or partially threaded shank with coarse, wood-gripping threads and a pointed tip. Their six-sided head allows for easy tightening with standard wrenches and sockets, and the stainless steel construction provides reliable performance in corrosive and moisture-heavy environments.

Stainless Steel (SS) 18-8

• Stainless Steel 18-8 hex lag screws have a higher corrosion resistance than zinc or HDG alternatives
• These are often used around chemicals or saltwater, and in applications requiring a clean, polished appearance

5/16 x 1 1/4 SS 18-8 Hex Lag Screw Features

• High torque capacity due to the six-sided head, allowing use with wrenches, ratchets, and impact drivers
• Coarse, aggressive thread pattern designed to bite into wood fibers for a strong, secure hold
• Corrosion and scratch resistant, durable when submerged in water or exposed to mild chemicals

Common Uses

• Marine construction, docks, and boat building involving wood components
• Coastal and waterfront structures including boardwalks, piers, and outdoor decking
• Water treatment facilities, chemical handling environments, and applications requiring a clean aesthetic finish

Application

• Always pre-drill a pilot hole to prevent wood splitting and ease installation
• Use a wrench, socket, or impact driver sized to the hex head
• Do not require a nut — threads bite directly into the wood substrate for holding power

Tips

• Always use a washer under the head to distribute load and prevent the head from digging into the wood surface
• Hex lag screws are measured from directly under the head to the tip of the shank
• Use stainless steel washers to avoid galvanic corrosion when pairing with SS 18-8 fasteners