Simpson #8 x 1-1/4" Truss-Head Screw in 305 Stainless Steel is a precision-engineered fastener from Simpson, designed for securing a wide range of materials to wood and wood-substrate surfaces. Built from Type 305 stainless steel, this screw delivers reliable corrosion resistance that makes it well-suited for outdoor, coastal, and moisture-prone applications. The oversized truss head distributes load across a broader bearing surface, while the Type-17 point and coarse threads allow for confident, efficient driving into wood substrates without pre-drilling in most cases.

Key Features

• Type 305 stainless steel construction - resists rust and corrosion in humid, wet, and outdoor environments, extending the service life of the fastened connection
• Truss head profile with 0.374" head diameter - the wide, low-profile head spreads clamping force over a larger surface area, reducing the risk of pull-through in softer substrates
• #2 square drive - provides positive bit engagement and reduces cam-out compared to Phillips drive, giving the installer better torque control and a cleaner finish
• Type-17 point - cuts into wood fibers rather than pushing them aside, enabling fast starts and reducing the need for pre-drilling in many wood applications
• Coarse thread pattern - maximizes holding strength in wood and wood-composite materials, pulling materials tightly together for a secure, stable connection
• #8 diameter, 1-1/4" length - a compact, versatile sizing that works across a broad range of light- to medium-duty fastening tasks in wood-substrate assemblies

Why This Product

• Corrosion-resistant material for demanding environments - Type 305 stainless steel holds up in wet, outdoor, and high-humidity conditions where zinc-plated or uncoated fasteners would corrode and fail prematurely
• Reduced cam-out frustration - the #2 square drive bit engagement keeps the driver locked in place during installation, saving time and reducing stripped heads on job sites
• Faster, cleaner installation into wood - the Type-17 point and coarse thread combination means the screw self-starts and seats firmly without wandering, making it a dependable choice for wood-to-wood and material-to-wood assemblies
• Broad material compatibility - the truss head and coarse thread design make this screw effective for attaching a variety of materials to wood or wood-composite substrates, adding versatility to a single fastener solution

Specifications

• Brand: Simpson Strong-Tie
• Screw Size: #8
• Length: 1-1/4 in.
• Head Diameter: 0.374 in.
• Head Type: Truss Head
• Drive Type: #2 Square
• Thread Type: Coarse Threads
• Point Type: Type-17 Point
• Material: Type 305 Stainless Steel
• Country of Origin: Taiwan

Available Pack Options

• S08C125TSC: 100 Pk
• S08C125TSM: 1000 Pk

Frequently Asked Questions

Do I need to pre-drill before driving this screw?

Pre-drilling is recommended depending on the substrate. The Type-17 point is designed to self-start in many wood applications, but harder or denser substrates may benefit from a pilot hole to prevent splitting and ensure accurate placement.

What drive bit do I need for this screw?

This screw uses a #2 square drive. Simpson recommends replacement bit model BIT2S-2 for driving these fasteners.

What materials can this screw be used to fasten?

The truss-head screw is ideal for securing all materials to wood or wood-substrate materials. The coarse thread and Type-17 point work together to pull materials firmly into the wood base.

Why is the truss head style beneficial compared to a standard flat or pan head?

The truss head features a wider diameter of 0.374 in. and a low profile, which distributes clamping load over a larger surface area. This reduces the chance of pull-through in softer or thinner materials and produces a clean, low-profile appearance once installed.