Simpson #12 x 1-1/2" Self-Drilling Hex-Washer Head Screw in 316 Stainless Steel is a precision fastener engineered for reliable performance in demanding environments. Designed with a #3 drill point and tapping screw threads, this hex-washer head screw drives cleanly into aluminum and fiberglass without pre-drilling, saving time on the job. The 316 stainless steel construction delivers exceptional resistance to corrosion, saltwater exposure, and harsh outdoor conditions - making it a trusted choice for marine, coastal, and exterior applications where standard fasteners would fail.

Key Features

• 316 Stainless Steel construction - provides superior corrosion resistance compared to standard 304 stainless, making it ideal for saltwater, coastal, and chemically aggressive environments
• #3 drill point (self-drilling tip) - eliminates the need for pre-drilling pilot holes in aluminum and fiberglass, reducing installation steps and labor time
• Tapping screw thread at 14 TPI - cuts its own mating threads as it drives, creating a secure, vibration-resistant hold in compatible materials
• Indented hex-washer head with 5/16 in. hex drive - the integrated washer distributes clamping load over a wider surface area, reducing material stress and improving pull-through resistance
• #12 diameter x 1-1/2 in. length - a robust fastener size that delivers strong holding power in thin-to-medium thickness aluminum panels and fiberglass sections
• Simpson brand quality - engineered to consistent tolerances so every screw drives predictably and seats flush, minimizing installation rejects

Why This Product

• When fastening aluminum framing, gutters, or fiberglass panels, this self-drilling screw removes the extra step of pilot hole drilling - the #3 drill point bores and taps in a single pass, speeding up production and field installation alike
• The 316 stainless steel alloy is specifically chosen for environments where moisture, salt air, or chemical exposure would quickly corrode carbon steel or zinc-plated fasteners - giving your finished assembly lasting structural integrity
• The hex-washer head style provides a positive wrench engagement that resists cam-out under power driving, and the integrated washer prevents the fastener from pulling through softer substrate materials like fiberglass skins
• This screw is explicitly rated for aluminum and fiberglass applications - not for steel - so specifying it correctly avoids galvanic corrosion issues that arise when dissimilar metals are improperly paired

Specifications

• Brand: Simpson Strong-Tie
• Screw Size: #12
• Length: 1-1/2 in.
• Material / Coating: Type 316 Stainless Steel
• Head Type: Hex Washer Head (Indented)
• Drive Type: 5/16 in. Hex
• Thread Type: Tapping Threads
• TPI: 14
• Point Type: #3 Drill Point
• Country of Origin: Taiwan

Available Pack Options

• T12150HDUC: 100 Pk
• T12150HDUM: 1000 Pk

Approved Applications

• Fastening aluminum panels, framing, and trim components
• Securing fiberglass sheets, enclosures, and structural panels
• Marine and coastal construction where corrosion resistance is critical
• Exterior applications exposed to moisture, humidity, or salt air

Frequently Asked Questions

Can this screw be used to fasten into steel?

No. This self-drilling hex-washer head screw is designed specifically for aluminum and fiberglass fastening. It is not recommended for use in steel applications. Using it in steel may result in galvanic corrosion or inadequate holding performance.

What is the difference between 316 stainless steel and standard 304 stainless, and why does it matter?

316 stainless steel contains added molybdenum, which gives it greater resistance to chlorides, saltwater, and industrial chemicals compared to 304 stainless. For fasteners used in marine environments, coastal installations, or anywhere exposed to salt air, 316 stainless is the preferred specification for long-term corrosion protection.

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

No pre-drilling is required. The #3 drill point on this screw is a self-drilling tip that bores through the substrate and taps its own threads in a single operation, making installation faster and more efficient in aluminum and fiberglass materials.

What tool do I need to drive this screw?

This screw uses a 5/16 in. hex (hex-washer) drive. A power driver or nut driver fitted with a 5/16 in. hex bit is the appropriate tool for installation. The hex drive provides strong torque engagement and reduces the risk of cam-out during driving.

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