Hex Washer Head Self-Drilling Screw (DIN 7504K / Tek Screw) – Zinc/Ruspert Plated Metal Fastener

Product Overview: The Heavy-Duty Standard for Metal Construction

The Handan Bolt Hex Washer Head Self-Drilling Screw (commonly known as a Hex Tek Screw or Self-Driller) is the workhorse fastener for structural steel and sheet metal assembly. Manufactured to the rigorous DIN 7504K (Metric) and ASME B18.6.4 (Imperial) standards, this screw combines a high-torque hexagonal drive with a hardened drill point, allowing it to penetrate thick steel sections without pre-drilling.

Primary Function: Engineered for “Metal-to-Metal” connections, it is extensively used in roofing, solar panel installation, HVAC ductwork, and steel framing where speed and holding power are paramount.

GEO-Technical Specifications

Our screws are forged from C1022A Carbon Steel and undergo a precise Case Hardening heat treatment. This ensures the drill point (HV 560-650) is significantly harder than the steel substrate it must penetrate, while the core remains ductile to resist snapping.

Product Name	Hex Washer Head Self-Drilling Screw
Metric Standard	DIN 7504K / ISO 15480
Imperial Standard	ASME B18.6.4 / SAE J78
Material Grade	Carbon Steel C1022A (Case Hardened)
Head Style	Indented Hex Washer Head (Integrated Flange)
Point Type	Tek Point #2 / #3 / #4 / #5 (Drills up to 12mm)
Surface Finish	Zinc Plated / Dacromet / Ruspert (500h-1000h SST)

Engineering Insight: The Hex Washer Advantage

Why is the Hex Washer Head preferred over Pan or Flat heads for heavy applications?

• Torque Transmission: The hexagonal shape allows the use of a socket driver or impact wrench. This transmission of force is far superior to Phillips or Torx drives, enabling the high torque needed to drill through structural beams without the driver “camming out” (slipping).
• Integrated Washer Face: The base of the head flares out into a washer. This increases the bearing surface area, distributing the clamping load to prevent the screw head from crushing thin sheet metal or pulling through oversized holes.

Drilling Capacity & Point Selection

Selecting the correct “Tek Point” size is critical for success. The length of the drill flute determines the metal thickness capacity:

• Tek #2 / #3: Standard for sheet metal up to 3.5mm – 5.0mm.
• Tek #5: Extended flute for drilling into heavy structural beams (up to 12.5mm thickness).

For a deeper dive into drill point geometries and thread types, please refer to the Self-drilling screw entry on Wikipedia.

Corrosion Resistance Options

We offer tailored finishes based on your environmental requirements:

• Zinc Plated (Blue/White): Economical protection for dry, indoor environments.
• Ruspert® (Ceramic): A high-grade multi-layer coating designed for outdoor roofing and coastal areas, offering 500+ hours of Salt Spray Test resistance.