Self-drilling screw countersunk head | A2 | DIN 7504O

This self-drilling screw with countersunk head is manufactured from high-quality A2 stainless steel, providing good corrosion resistance and long durability even in demanding environments. The Countersunk Self-Drilling Screw | A2 | DIN 7504O has a surface and core hardness of approximately 200 HV. Its self-drilling capacity and torsional resistance correspond to those of stainless steel self-drilling screws according to ISO 3506-4.

Please note that these self-drilling screws are suitable for drilling and self-tapping into softer materials such as aluminium, plastic, and plasterboard. For use in harder materials, such as sheet metal, we recommend self-drilling screws with a hardened tip, such as electro-galvanized (FZB) self-drilling screws.

AREA OF APPLICATION

Primarily used for assembly in metal and wood structures where a flush and discreet fastening is desired. Thanks to its stainless steel construction, it is well-suited for both indoor and outdoor use, particularly in environments exposed to moisture and weathering.

The countersunk head provides a flush mount against the surface, creating a sleek and professional finish—ideal for visible fastenings.

TECHNICAL SPECIFICATIONS

Product type: Self-drilling sheet metal screw

Standard: Similar to DIN 7504 O

Material: Stainless steel A2 (AISI 304)

Hardness: approx. 200 HV

Head shape: Countersunk

Drive type: Torx

FREQUENTLY ASKED QUESTIONS (FAQ)

What do the standards DIN 7504O and ISO 3506-4 mean for this self-drilling screw?

DIN 7504O (also corresponds to ISO 15482) specifies the geometry of a self-drilling screw with a countersunk head and drill point. Combined with ISO 3506-4, the screw's mechanical performance is ensured:

• Integrated torque sequence: The screw drills the hole, cuts the mating thread, and pulls the joint together in one quick operation without pre-drilling.

• Torsional strength: Designed to withstand the torque (torsion) that occurs during the drilling and threading process so that the screw does not shear off when used correctly.

In which materials can the A2 self-drilling screw (DIN 7504O) be used directly?

A2 stainless steel has a homogeneous surface and core hardness of approx. 200 HV (Vickers). This provides a tough screw with high resistance to corrosion, but limits its cutting capacity in hard metals.

• Suitable materials: Aluminium profiles, plastic, plasterboard, wood and composite materials, as well as softer plastic laminates.

• Unsuitable materials: Harder steel plate or stainless steel sheet. For these, either pre-drilling or a bi-metal screw is required (alternatively, electro-galvanized/FZB with a hardened drill point).

Technical advice: If you attempt to drill into standard steel plate with a pure A2 screw, the drill point will quickly become hot, lose its sharpness, and work-harden the metal without penetrating.

What is the advantage of a countersunk head (Form O) during assembly?

The countersunk head shape is drawn down completely flush into the material (or into countersunk holes in fittings):

• Smooth surface: Ideal for panel assembly, cover plates, or profiles where no screw heads must interfere with adjacent components or pose a tripping/abrasion hazard.

• Excellent corrosion protection: Stainless steel A2 (AISI 304 / 1.4301) effectively protects against moisture, outdoor climates, and condensation in industrial and outdoor environments.