Simpson #12 x 1" Self-Drilling Hex-Washer Head Screw in 316 Stainless Steel is a heavy-duty fastener engineered for reliable performance in corrosive and moisture-prone environments. Built from Type 316 stainless steel - the grade prized for superior resistance to saltwater, chemicals, and coastal weather conditions - this self-drilling screw eliminates the need for a separate pre-drilled pilot hole, saving time and effort during installation. With a hex-washer head driven by a 5/16 in. hex bit and tapping threads at 14 TPI, it delivers a secure, vibration-resistant grip in aluminum and fiberglass applications where dependable fastening is essential.

Key Features

• Type 316 stainless steel construction - provides exceptional resistance to corrosion, oxidation, and chemical exposure, making it a dependable choice for marine, coastal, and outdoor installations
• Self-drilling #3 drill point - bores its own pilot hole as it drives, reducing installation steps and speeding up the fastening process without sacrificing holding strength
• Indented hex-washer head with 5/16 in. hex drive - distributes clamping load over a wider surface area for a more secure seat and reduces the chance of fastener pull-through in softer materials
• Tapping screw thread at 14 TPI - cuts its own mating threads into the base material, creating a strong mechanical lock that resists loosening under vibration or movement
• #12 screw diameter x 1" length - a versatile size well-suited for thin-gauge aluminum panels, fiberglass sheets, and similar lightweight substrates where a compact but robust fastener is needed

Why This Product

• Type 316 stainless steel offers measurably greater corrosion resistance than standard 304 stainless - making these screws a practical solution for applications exposed to moisture, salt air, or harsh outdoor conditions where fastener longevity matters
• The self-drilling point means no separate drill bit or pre-drilling step is required when working with aluminum or fiberglass, reducing tool changes and accelerating project timelines
• The hex-washer head design provides a broader bearing surface than a standard hex head alone, helping to prevent pull-through and ensuring a flush, stable connection in panel and cladding applications
• Specifically suited for aluminum and fiberglass fastening - not steel - this screw is purpose-matched to the materials where it performs best, helping installers avoid misapplication and achieve consistent, reliable results

Specifications

• Brand: Simpson Strong-Tie
• Coating/Material: Type 316 Stainless Steel
• Screw Size: #12
• Length: 1 in.
• Head Type: Hex Washer Head
• Drive Type: 5/16 in. Hex
• Thread Type: Tapping Threads
• TPI: 14
• Point Type: #3 Drill Point
• Country of Origin: Taiwan

Available Pack Options

• T12100HDUC: 100 Pk
• T12100HDUM: 1000 Pk

Approved Applications

• Fastening aluminum panels and aluminum sheet assemblies
• Securing fiberglass panels, enclosures, and structural fiberglass components
• Coastal, marine, and high-humidity environments where corrosion resistance is a priority
• Outdoor cladding and panel installations where a self-drilling fastener eliminates pre-drilling steps

Frequently Asked Questions

Can this screw be used to fasten into steel substrates?

No. This screw is specifically designed for aluminum and fiberglass fastening and is not intended for use in steel. Using it in steel can compromise the drill point and result in a failed or insecure connection. Always match the fastener to the correct substrate.

What drive tool is needed to install this screw?

This screw uses a 5/16 in. hex (socket) drive. A standard hex-head driver bit or nut-setter in the 5/16 in. size - used with a power drill or impact driver - is all that is needed for installation.

Why is Type 316 stainless steel preferred over 304 stainless for outdoor or coastal applications?

Type 316 stainless steel contains molybdenum, which provides enhanced resistance to pitting corrosion caused by chlorides - such as those found in seawater and salt air. This makes 316 SS a more durable choice than 304 in marine, coastal, and chemically exposed environments.

Does this screw require a pre-drilled pilot hole?

No. The #3 drill point is a self-drilling tip that bores through the base material as the screw is driven. This eliminates the need for a separate pilot hole when working with aluminum or fiberglass, streamlining the installation process.

Note: Product dimensions and/or thread length may differ from picture. Please see the item description above for specifications.