Best Bolts and Screws for Attaching Wood to Metal: Types & Guide

Wood-to-metal connections are essential in construction, carpentry, and industrial projects, requiring the right fasteners for strong, durable joints. Choosing the best bolt or screw depends on factors like load capacity, corrosion resistance, and ease of installation. This guide covers the best bolts and screws for wood-to-metal connections and how to pick the right one for your needs.

Types of Bolts and Screws for Wood-to-Metal Attachments

Selecting the right fastener for joining wood to metal ensures structural integrity and long-term durability. Here are the most common options:

🔹 Lag Bolts (Lag Screws)

• Best for: Heavy-duty applications, outdoor structures, framing, and fencing.
• Features: Thick, coarse threads that grip wood securely; requires pre-drilling.
• Why Choose It? Ideal for high-load structures connecting wood to steel brackets or plates.

🔹 Self-Drilling Screws (Tek Screws)

• Best for: Fast and easy wood-to-metal fastening without pre-drilling.
• Features: Built-in drill tip for penetrating metal; coarse threads for wood grip.
• Why Choose It? Great for roofing, decking, and industrial construction.

🔹 Carriage Bolts with Nuts & Washers

• Best for: Heavy-duty connections in decks, timber frames, and outdoor projects.
• Features: Smooth, rounded head for a finished look; requires a nut and washer.
• Why Choose It? Provides strong mechanical joints in load-bearing applications.

🔹 Machine Screws with T-Nuts or Metal Inserts

• Best for: Furniture, cabinetry, and light-duty wood-to-metal connections.
• Features: Threaded shaft designed for pre-threaded metal inserts.
• Why Choose It? Ideal for aesthetic and removable joints in modular builds.

🔹 Threaded Rods with Nuts & Washers

• Best for: High-strength structural applications.
• Features: Fully threaded, allowing for custom lengths and deep wood penetration.
• Why Choose It? Offers maximum load-bearing capacity in heavy-duty connections.

How to Choose the Right Fastener for Your Project

When selecting a bolt or screw for wood-to-metal applications, consider these factors:

✅ Load Capacity

• Light-duty applications: Use self-drilling screws or machine screws.
• Medium-duty applications: Choose lag screws or carriage bolts.
• Heavy-duty applications: Go with threaded rods or high-strength bolts with washers and nuts.

✅ Corrosion Resistance

• For outdoor or high-moisture areas: Use stainless steel, hot-dip galvanized, or coated fasteners.
• For indoor applications: Zinc-plated or plain steel screws may be sufficient.

✅ Ease of Installation

• If speed matters, self-drilling screws are best.
• If maximum strength is required, bolts with nuts and washers provide the most secure attachment.

✅ Wood Type & Thickness

• Softwoods (e.g., pine, cedar): Use coarse-threaded fasteners for strong grip.
• Hardwoods (e.g., oak, maple): Pre-drilling may be necessary to prevent splitting.

✅ Metal Type & Thickness

• For thin sheet metal: Use self-drilling screws or machine screws with nuts.
• For thick steel beams: Choose lag bolts, carriage bolts, or threaded rods.

Final Thoughts

Choosing the right bolt or screw for wood-to-metal connections depends on load requirements, corrosion resistance, and ease of installation. Lag screws, self-drilling screws, carriage bolts, and threaded rods are among the most popular fasteners in North American construction and woodworking. Making the right selection ensures strong, durable, and reliable connections in any project. Always consider wood and metal thickness, environmental conditions, and fastening strength before making your choice.

Need expert advice on fasteners? Contact a fastener specialist to find the best solution for your project!