Countersunk Self-Tapping Screws

Countersunk Self-Tapping Screws DIN 7982 | ST2.9–ST6.3 | Flush-Finish Sheet Metal Screws

Countersunk self-tapping screws manufactured to DIN 7982 feature a flat countersunk head that sits flush with the material surface when installed. These screws combine self-tapping capability with a clean, flush finish, making them ideal for applications where protruding heads would interfere with adjacent components or aesthetics. Available in ST2.9 to ST6.3 sizes with Phillips or Pozi drive options.

Material & Specifications

Size Range	ST2.9 to ST6.3 (#6 to #14)
Standard	DIN 7982, ISO 7050, ANSI B18.6.4
Material	Carbon Steel (Case Hardened), 410 SS, 304 SS
Surface / Coating	Zinc Plated (Cr3+ RoHS), Black Oxide, Ceramic Coated
Head Type	Countersunk flat head with Phillips / Pozi / Torx drive
Thread Type	Type A (sharp point), Type AB (gimlet point)

Surface Treatment & Zinc Coating Quality

At BoltNutsPlus, we understand that surface treatment is critical to fastener longevity and performance. Our products undergo rigorous coating processes to ensure maximum corrosion resistance and durability. We offer five premium coating options, each tested to international standards:

• Hot-Dip Galvanizing (HDG) — Thick zinc layer (50-120μm) providing superior long-term corrosion protection for outdoor, marine, and industrial environments. Compliant with ISO 1461 / ASTM A153 standards. Salt spray resistance: 500-1,000+ hours. Ideal for structural steel assemblies exposed to harsh weather.
• Electroplated Zinc Blue-White (Zn Blue/White) — Bright, clean silver-blue appearance with 5-15μm zinc layer. Cr3+ passivation technology, fully RoHS compliant. Ideal for indoor machinery, electronics, and general-purpose applications requiring aesthetic appeal and moderate corrosion resistance.
• Color Zinc / Yellow Zinc (Iridescent Passivation) — Multi-colored iridescent passivation film offering enhanced corrosion resistance (100-200 hours salt spray) with a distinctive golden finish. Widely preferred in automotive, agricultural equipment, and construction machinery sectors for its balanced protection and visual appeal.
• Dacromet Coating — Advanced water-based zinc-chromium coating technology with NO hydrogen embrittlement risk. Provides 1,000+ hours salt spray resistance, making it the preferred choice for high-strength fasteners in extreme environments. Environmentally friendly (no heavy metal discharge), RoHS/ELV compliant, ideal for automotive and wind energy applications.
• Multi-Element Alloy Co-Permeation — Zinc-aluminum-rare earth alloy layer offering 2-3x the corrosion resistance of traditional galvanizing. Features self-healing properties at scratch points, ensuring long-term protection even in damaged areas. Ideal for critical infrastructure, power transmission towers, coastal projects, and marine installations.

Key Features

• Countersunk head sits flush with surface for clean, professional finish
• Self-tapping design eliminates pre-drilling in most sheet metal applications
• Case-hardened threads for sharp cutting and long service life
• Multiple drive options: Phillips, Pozi, Torx for various torque requirements
• Corrosion-resistant zinc plating suitable for indoor and sheltered outdoor use
• Ideal for applications where protruding screw heads would cause interference

Applications

• Sheet metal enclosure and cabinet assembly requiring flush finish
• Door and window frame installation in metal cladding
• Automotive interior panel and trim fastening
• Electronic equipment housing assembly
• Furniture and cabinet making with metal components
• General sheet metal fastening where flush surface is required

Why Choose BoltNutsPlus?

• ISO 9001:2015 Certified Manufacturing — consistent quality you can trust on every batch
• 15+ Years of Export Experience — serving 40+ countries across 6 continents
• Full Traceability — material certificates (EN 10204 3.1) and comprehensive test reports included
• Custom Packaging & OEM/ODM — your brand identity, your specifications, our precision manufacturing
• Third-Party SGS / Bureau Veritas Inspection Available upon request
• 24-Hour Quote Response — same-day reply for urgent requirements; standard 24-hour turnaround