Product Summary

لونجزي Hex Washer Head Self-Drilling Screws (also known as Tek Screws) are high-performance fasteners manufactured according to DIN 7504K و ISO 15480 standards, widely used in metal roofing, steel

building construction, HVAC ducting, and industrial siding. Featuring a drill-point tip and an integrated hex washer head, these لونجزي Hex Washer Head Self-Drilling Screws drill their own pilot hole, tap

their own thread, and secure the connection in a single operation, significantly reducing installation time and labor costs.

• ✔ Integrated EPDM Sealing: Available with EPDM Bonded Washers to create a 100% watertight seal, preventing leaks in roofing and cladding applications.

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• ✔ Rapid Drill-Point Technology: Precision-engineered tips (Point #2 to #5) capable of penetrating steel plates up to 12 mm thick without pre-drilling.

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• ✔ High Torque Stability: The hexagonal head provides a non-slip drive surface for power nut setters, ensuring safe and efficient installation on high-speed construction sites.

Key Features of Hex Washer Head Self-Drilling Screws

• 3-in-1 Fastening Solution – Combines drilling, tapping, and fastening into one step, eliminating the need for separate drill bits.

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• Superior Weather Resistance – Offered with high-grade Dacromet أو Zinc-Flake coatings that withstand over 1,000 hours of salt spray testing.

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• Vibration-Proof Seal – The EPDM Bonded Washer acts as a cushion, absorbing thermal expansion and mechanical vibration while protecting the metal sheet.

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• Wide Material Compatibility – Designed for securing metal-to-metal and metal-to-timber connections in heavy industrial environments.

Technical Specifications

• Standards: DIN 7504K / ISO 15480 / ASME B18.6.4 / SAE J78

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• Metric Size Range: ST3.5 to ST6.3 (Diameter)

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• Inch Size Range: #6 to 5/16" (Diameter)

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• Length Range: 13 mm to 250 mm

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• Drill Point Types: #2, #3, #4, #5 (Extra Deep Drilling)

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• Finish: Zinc Plated (Blue/Yellow), Ruspert (Silver/Grey), Dacromet, Ceramic Coated

• Material & Mechanical Properties

• مادة	درجة	Core Hardness	Surface Hardness	Drilling Capacity
  Carbon Steel	C1022A (Hardened)	270 to 390 HV	$\ge 560$ HV	Steel up to 12 mm
  الفولاذ المقاوم للصدأ	SS410 (Hardened)	350 to 450 HV	$\ge 500$ HV	Aluminum / Thin Steel
  Bi-Metal	SS304 + Steel Tip	240 to 300 HV	$\ge 550$ HV (Tip)	Stainless Steel Plates

• Standard Dimensions (Metric DIN 7504K)

• Size (ST)	Washer Head Dia (dk)	Head Height (k)	Socket Size (s)	Drill Tip Length
  ST4.2	8.80 mm	4.10 mm	7.0 mm	3.5 to 4.5 mm
  ST4.8	10.50 mm	4.45 mm	8.0 mm (5/16")	4.0 to 6.0 mm
  ST5.5	11.00 mm	5.40 mm	8.0 mm (5/16")	5.0 to 8.0 mm
  ST6.3	13.50 mm	6.45 mm	10.0 mm (3/8")	6.0 to 12.0 mm

• Surface Treatment

• Coating	Process	Salt Spray	طلب
  Zinc Plated	Electroplating	72 to 144h	General Indoor Steel
  Ruspert	Ceramic Coating	500 to 1500h	Roofing / Coastal Areas
  Dacromet	Zinc-Flake	1000+h	Heavy Industrial Construction
  XYLAN / PTFE	Polymer	1000+h	Chemical Plants / Offshore