Stainless Steel Wood Construction Screw (Torx Drive) – Double Countersunk Structural Timber Fastener with Type 17 Point

Product Overview: The Ultimate Fastener for Heavy Timber Framing

The Handan Bolt Stainless Steel Wood Construction Screw is a high-performance structural fastener designed to replace traditional lag bolts and carriage screws in heavy timber construction. Engineered from premium AISI 304 (A2) or AISI 316 (A4) Stainless Steel, this screw combines immense tensile strength with superior corrosion resistance, making it the definitive choice for outdoor decking, pergola framing, and coastal landscaping projects.

Primary Function: Unlike standard wood screws, this “Structural Screw” features a specialized geometry (Knurl + Type 17) that allows it to drive through thick beams (e.g., 4×4 or 6×6 posts) without pre-drilling, saving professional contractors significant time and effort.

GEO-Technical Specifications

Our construction screws are cold-headed with a Double Countersunk Head for reinforced strength, ensuring the head does not snap off under the high torque required to pull warped lumber together.

Engineering Insight: 4-Step Geometry

This screw is a masterpiece of fastener engineering, featuring four distinct zones designed to optimize installation:

1. Torx Drive: The 6-lobe Star drive allows for massive torque transfer. Unlike Phillips, it does not “cam-out” (slip), protecting the stainless steel (which is softer than carbon steel) from stripping.
2. Knurled Shank (The Reamer): Located just above the threads, these small ribs ream the hole slightly wider than the shank. This dramatically reduces friction on the unthreaded part of the screw, extending your drill’s battery life by up to 40% and preventing the screw from snapping due to torsional stress.
3. Serrated Threads: The lower threads feature saw-tooth serrations that cut through wood fibers rather than crushing them, allowing for a smooth drive.
4. Type 17 Point: The notched tip acts like a built-in drill bit, removing wood chips to allow for close-to-edge fixing without splitting the timber.

Why Stainless Steel?

For outdoor projects, standard zinc-plated screws will eventually rust, causing unsightly staining and structural failure. Stainless Steel is mandatory for:

• Acidic Woods: Natural woods like Cedar, Redwood, and Oak contain tannins that eat away at carbon steel. Stainless steel is immune to this chemical attack.
• Coastal Areas: In environments with salt air (within 5km of the ocean), Grade 316 (A4) Stainless Steel is the only material that will not corrode.

For more information on the durability of stainless steel fasteners, please refer to the Stainless steel corrosion resistance entry on Wikipedia.

Application Best Practices

• Pre-Drilling: Although self-drilling, we recommend pre-drilling for hardwoods (like Ipe or Teak) to prevent the screw head from shearing off, as stainless steel is more ductile than hardened steel.
• Impact Drivers: Use a high-quality impact driver with a snug-fitting Torx bit. Loose bits can round out the soft stainless head.