Hex Self-Drilling Screws with Drill Point in Carbon Steel and Stainless Steel for Construction

Hex Self-Drilling Screws with Drill Point – DIN 7504‑K / ISO 15480

Hexagon washer head self‑drilling screw manufactured to DIN 7504‑K (superseded by ISO 15480), with an integral flange washer under the hex head and a built‑in drill point that drills its own pilot hole and forms the mating thread in a single operation. The screw incorporates a tapping thread to ISO 1478, with a case‑hardened drill point eliminating pre‑drilling in steel, aluminium, plastics, and timber‑to‑steel connections. Thread sizes ST2.9 to ST6.3, lengths from 9.5 mm to 300 mm. Carbon steel (SAE J403 1022) and stainless steel (A2‑304, A4‑316, 410) variants with finishes including zinc plating, black zinc, Dacromet, and painted RAL colours. Widely used in roofing, cladding, metal framing, HVAC, and general construction where single‑side access and rapid installation are required.

What are the exact dimensional specifications for DIN 7504‑K hexagon washer head self‑drilling screws?

Thread sizes from ST2.9 to ST6.3 with metric coarse pitches ranging from 1.1 mm to 1.8 mm. Head height varies between 2.5 mm and 5.9 mm; washer diameter from 5.8 mm up to 13.5 mm; across flats from 3.82 mm to 9.78 mm; and drill point maximum diameter from 2.3 mm to 5.8 mm, depending on thread size. Length measured from under the head to the tip. DIN 7504‑K and ISO 15480 are interchangeable, with ISO 15480 omitting the drill point diameter specification.

What drill point types are available and what material thickness can each drill through?

Drill points are classified by point length as Tek #2, #3, #4, #5, and #7 (Tek 7 being the longest). Maximum drillable combined material thickness ranges from 0.9 mm (#2) up to 19.1 mm (#7). For timber‑to‑steel applications, wings (reamers) are added above the drill point to oversize the hole in wood, preventing thread engagement until the metal is reached; wings snap off upon contact with steel.

What are the mechanical property, hardness, and torsional strength requirements?

Carbon steel screws are manufactured from SAE J403 1022 with case hardening. Surface hardness exceeds 500 HV, core hardness 240‑450 HV, and case depths vary by thread size from 0.05 mm to 0.28 mm. Alternative Rockwell specification: HRC 32‑40. Minimum torsional strength ranges from 24 Lb/in for ST3.5 up to 150 Lb/in for ST6.3. Drilling time depends on diameter and material thickness, typically 4 to 13 seconds. Stainless steel grades (A2‑304, A4‑316, 410) are also available with appropriate hardness for their material class.

FAQ

Q:Are you a factory or trading company?

A: We are factories, mainly producing fasteners, such as nuts, bolts, screws and rods, and meanwhile, we also manage other hardware products.

Q: Where is your factory located? How can I visit there?

A: Our factory is located in Jiaxing City, Zhejiang Province with a good location and convenient transportation, which is next to Shanghai Port, Ningbo Port and Zhapu Port.

Q: How does your factory do regarding quality control?

A: "Quality is priority" we supervise each production link and we always attach great importance to quality controlling from the beginning to the end.