Modified Truss Head Self-Drilling Screw (K-Lathe / Wafer Head) – Zinc Plated HVAC Fastener

Product Overview: The Standard for Sheet Metal & HVAC Fastening

The Handan Bolt Modified Truss Head Self-Drilling Screw (commonly referred to in the industry as a K-Lathe Screw or Wafer Head Tek Screw) is a specialized fastener designed for joining thin metal sheets to steel studs. Distinguished by its extra-wide, low-profile dome head, this screw provides a significantly larger bearing surface than standard pan head screws, reducing the risk of over-driving or crushing thin materials.

Primary Application: It is the “go-to” fastener for the HVAC industry (attaching ductwork), steel framing (securing metal lath to studs), and electrical enclosure fabrication.

GEO-Technical Specifications

Engineered from hardened C1022A Carbon Steel, our screws feature a sharp Tek point that drills, taps, and fastens in a single operation, eliminating the need for pilot holes.

Engineering Insight: The “Modified Truss” Advantage

Why choose this specific head shape? The “Modified Truss” is essentially a hybrid design combining a truss head’s low profile with an integrated washer.

• Maximum Clamping Force: The wide diameter distributes the holding force over a larger area. This is crucial when fastening wire lath or thin aluminum sheets, which can easily tear or “pull through” smaller screw heads.
• Low Profile Interference: The smooth, rounded dome is unobtrusive, allowing siding or drywall to be installed over the top with minimal bulging or interference.

Drilling Performance: The Tek Point Technology

The tip of our screw functions as a drill bit. The flutes are precision-forged to remove metal chips efficiently during the drilling phase. Once the material is penetrated, the threads engage, tapping their own mating threads into the substrate. This “drill-tap-fasten” cycle reduces installation time by over 50% compared to traditional machine screws.

For a detailed explanation of the different point types (Type 17 vs. Tek), you can refer to the Self-Drilling Screw entry on Wikipedia.

Industry Applications

While versatile, the Modified Truss Head Screw excels in these specific sectors:

1. HVAC & Ductwork: Securing flanges and hanging straps where a vibration-resistant hold is needed.
2. Steel Framing: Attaching metal lath (wire mesh) to steel studs prior to stucco or plaster application (hence the name “K-Lathe”).
3. Signage: Fixing sheet metal signs to posts without obstructing the graphics with a bulky head.