Simpson #12 x 1-1/2" Self-Drilling Hex-Washer Head Screw in 305 Stainless Steel is a high-performance fastener from Simpson designed for reliable attachment in aluminum and fiberglass applications. Built from Type 305 stainless steel, this screw delivers strong corrosion resistance in environments where standard steel fasteners would degrade - making it a dependable choice for contractors, builders, and DIYers working with non-ferrous materials. The self-drilling tip eliminates the need for pre-drilling pilot holes, saving time on the jobsite without sacrificing holding strength.

Key Features

• Type 305 stainless steel construction - provides corrosion resistance in humid, wet, and outdoor environments where standard screws would rust or stain
• Self-drilling #3 drill point - drives directly into aluminum and fiberglass without pre-drilling, reducing installation time and the need for additional tools
• Indented hex-washer head with 5/16 in. drive - delivers a secure, wrench-friendly grip that distributes clamping force evenly and resists pull-through
• Tapping screw thread at 14 TPI - cuts its own mating thread as it drives, creating a tight, vibration-resistant connection in softer substrate materials
• #12 screw size at 1-1/2 in. length - a versatile combination suited for a range of panel thicknesses and structural applications involving aluminum or fiberglass

Why This Product

• Engineered specifically for aluminum and fiberglass fastening - not just a general-purpose screw, this is a purpose-built fastener that handles non-ferrous materials without stripping or galling
• 305 stainless steel eliminates corrosion concerns - ideal for outdoor, coastal, or moisture-prone environments where carbon steel fasteners would fail prematurely
• Self-drilling point speeds up installation - no separate drilling step means fewer tool changes and faster project completion, particularly valuable on large paneling or cladding jobs
• Hex-washer head with tapping threads provides lasting holding power - the combined thread design and broad washer bearing surface resist loosening under load or vibration over time

Specifications

• Brand: Simpson Strong-Tie
• Screw Size: #12
• Length: 1-1/2 in.
• Material/Coating: Type 305 Stainless Steel
• Head Type: Indented Hex Washer Head
• Drive Type: 5/16 in. Hex
• Thread Type: Tapping Screw Thread
• TPI: 14
• Point Type: #3 Drill Point
• Country of Origin: Taiwan

Available Pack Options

• S12150HDUC: 100 Pk
• S12150HDUM: 1000 Pk

Approved Applications

• Fastening aluminum panels and components
• Fastening fiberglass panels and assemblies
• Note: Not intended for use in steel substrates

Frequently Asked Questions

Can this screw be used in steel applications?

No. This self-drilling hex-washer head screw is designed specifically for aluminum and fiberglass fastening. It is not recommended for use in steel substrates. For steel applications, a different screw designed for that material should be selected.

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

No pilot hole is required. The #3 self-drilling point is designed to penetrate aluminum and fiberglass on contact, allowing the screw to drive directly into the material and eliminating the need for a separate drilling step.

What tool is used to drive this screw?

This screw features a 5/16 in. indented hex head, so it is driven with a 5/16 in. hex driver or nut driver - compatible with standard drills, impact drivers, and hex-drive sockets.

Why is 305 stainless steel used for this fastener?

Type 305 stainless steel offers meaningful corrosion resistance, making these screws suitable for outdoor, humid, or moisture-exposed environments. This material choice also reduces the risk of galvanic corrosion when fastening aluminum, since stainless steel and aluminum are more compatible than carbon steel and aluminum in direct contact.

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