Product Summary

Largo Wafer Head Self-Drilling Screws (also known as Modified Truss Head Screws) are high-precision fasteners manufactured to DIN 7504 y ISO 15480 standards, widely used in metal-to-metal framing,

HVAC ductwork, cabinet installation, and electrical box mounting. Featuring an ultra-wide, low-profile head and a drill-point tip,

these Largo Wafer Head Self-Drilling Screws provide a massive bearing surface to secure thin materials without pulling through, while drilling their own pilot hole in a single, rapid operation.

• ✔ Extra-Wide Bearing Surface: The "Wafer" or "Modified Truss" head acts like an integrated washer, distributing clamping force over a larger area to prevent material deformation.

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• ✔ Low-Profile Aesthetic: The thin, flat-topped head provides a sleek, professional finish that doesn't interfere with moving parts or secondary layers.

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• ✔ High-Speed Drilling: Engineered with a precision #2 or #3 drill point to penetrate cold-rolled steel, aluminum, and galvanized tracks in seconds.

Key Features of Wafer Head Self-Drilling Screws

• Reduced "Pull-Through" – The large head diameter makes these screws the industry standard for securing vinyl siding, thin-gauge metal lath, and delicate components.

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• Flush-Like Finish – While not fully countersunk, the wafer head is thin enough to allow other materials to lay flat over the screw head.

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• Self-Drilling Efficiency – Eliminates the need for separate drill bits and tapping tools, reducing labor costs on large-scale construction projects.

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• Superior Drive Engagement – Deep Phillips #2 or Torx recesses ensure the driver bit remains seated, preventing "cam-out" and surface scratches.

Technical Specifications

• Standards: DIN 7504 (Modified) / ISO 15480 / ASME B18.6.4 / SAE J78

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• Metric Size Range: ST3.5 to ST6.3

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• Inch Size Range: #6 to #14

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• Length Range: 13 mm to 100 mm (1/2" to 4")

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• Drill Point Types: Point #2 (Standard) / Point #3 (Heavy Duty)

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• Drive Type: Phillips #2 (Standard) / Square / Torx (Star)

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• Finish: Zinc Plated (Clear/Blue/Yellow), Black Phosphate, Ruspert, Plain

• Material & Mechanical Properties

• Material	Calificación	Core Hardness	Surface Hardness	Drilling Capacity
  Carbon Steel	C1022A (Hardened)	270 to 390 HV	$\ge 560$ HV	Steel up to 4.5 mm
  Acero inoxidable	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 Wafer Head Type)

• Size (ST)	Head Dia (dk)	Head Height (k max)	Phillips No.	Drilling Max (Steel)
  ST4.2 (#8)	10.5 to 11.5 mm	2.20 mm	PH2	1.0 to 3.0 mm
  ST4.8 (#10)	11.0 to 12.0 mm	2.50 mm	PH2	1.5 to 4.0 mm
  ST5.5 (#12)	12.5 to 13.5 mm	3.00 mm	PH3	2.0 to 5.0 mm
  ST6.3 (#14)	13.5 to 14.5 mm	3.50 mm	PH3	2.5 to 6.0 mm

• Surface Treatment

• Coating	Process	Salt Spray	Solicitud
  Zinc Plated	Electroplating	72 to 144h	General Indoor Framing
  Black Phosphate	Chemical Dip	48 to 96h	Drywall / Steel Lath
  Ruspert	Ceramic Coating	500 to 1000h	Outdoor Cladding / HVAC
  Passivated	Chemical	1000+h	Stainless Steel Only