Simpson #8 x 2-1/2" Truss-Head Screw in 305 Stainless Steel is a precision-engineered fastener from Simpson designed to securely attach 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 a practical choice for demanding indoor and outdoor fastening applications. The oversized truss head, Type-17 point, and coarse-thread design work together to deliver strong holding power with efficient installation - whether you are working on structural assemblies, trim, or composite wood substrates.

Key Features

• Type 305 Stainless Steel construction - provides strong corrosion resistance, keeping fasteners secure and structurally sound in moisture-exposed or corrosive environments
• Truss head design with 0.374 in. head diameter - the low-profile oversized head distributes load across a wider surface area, reducing pullthrough and creating a cleaner, flush appearance in finished assemblies
• #2 Square drive - delivers positive bit engagement and reduces cam-out during installation, resulting in faster, more controlled driving compared to Phillips-style drives
• Type-17 point - the self-drilling tip bores into wood fibers efficiently, minimizing splitting and reducing the need for predrilling in many wood substrates
• Coarse threads - designed to grip wood fibers firmly, providing strong pull-out resistance and a tight, secure connection between materials and wood or wood-substrate bases
• #8 diameter x 2-1/2 in. length - a versatile size that provides solid penetration depth for reliable fastening without overdriving or compromising the substrate

Why This Product

• The Type 305 stainless steel material makes this screw a dependable choice where moisture or humidity could cause standard carbon steel fasteners to rust, corrode, or stain surrounding materials over time.
• The truss head profile is specifically engineered for applications where a wide bearing surface is needed - it seats flush without mushrooming or leaving sharp protrusions, making it well-suited for attaching panels, decking, or wood composites.
• The combination of a Type-17 self-drilling point and coarse threads means faster installation with less preparation - reducing the need for predrilling in wood and helping drive straight, consistent fasteners with each pass.
• The #2 square drive interface minimizes slippage and cam-out during installation, giving installers better torque control and cleaner results - particularly when working at awkward angles or with power tools.

Specifications

• Brand: Simpson Strong-Tie
• Screw Size: #8
• Length: 2-1/2 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

• S08C250TSC: 100 Pk
• S08C250TSM: 1000 Pk
• S08250TSBC: 2000 Pk

Frequently Asked Questions

What is the difference between a truss head and a standard pan or flat head screw?

A truss head features a low-profile, wider-diameter dome shape - in this case 0.374 in. across - that distributes clamping force over a larger surface area than a standard pan head. This reduces the risk of the screw pulling through softer or thinner materials, making it a preferred choice when fastening panels, sheeting, or composites to wood substrates.

Do I need to predrill before using this screw?

Predrilling is recommended depending on the substrate. The Type-17 point helps the screw self-start and bore into wood fibers without splitting, but for harder woods, dense composites, or applications near board edges, predrilling will help prevent cracking and ensure proper seating of the truss head.

What drive bit do I need to install this screw?

This screw uses a #2 square drive. The replacement bit compatible with this drive type is model BIT2S-2. Using the correct square drive bit helps maintain positive engagement and prevents cam-out during installation.

Is Type 305 stainless steel suitable for outdoor or wet environment use?

Type 305 stainless steel offers solid corrosion resistance, making it appropriate for many outdoor and moisture-exposed applications. It performs well in general exterior conditions where protection from rust and staining is important when fastening to wood or wood-substrate materials.