Meridyen Self-Drilling Screw YHB 3.9X25 (12,000 Pieces)

Meridyen Self-Drilling Screw YHB 3.9×25 mm — 12,000 Pieces

The Meridyen Self-Drilling Screw YHB 3.9×25 mm is a fastener designed to deliver deep, strong and permanent grip in thick multi-layer sheet metal assemblies and insulated roof and facade systems. The YHB wide-bearing head design distributes pressure evenly to prevent crushing the sheet and provides partial sealing protection. Supplied in a well-balanced pack of 12,000 pieces, it offers practical, continuous supply for both mass-production workshops and large construction sites.

Technical Specifications

• Brand: Meridyen
• Diameter × Length: 3.9 mm outer diameter, 25 mm working length beneath the head
• Head Type: YHB — wide bearing surface, washer-effect hexagonal flange head
• Thread Profile: Metal-specific deep thread form; holds firmly at every turn even through thick layers
• Point Feature: Self-drilling tip; forms its own pilot hole, no pre-drilling required
• Drive Type: Easily applied with standard hexagonal wrenches
• Surface Coating: Galvanized; corrosion-resistant, suitable for indoor and outdoor use
• Pack Contents: 12,000 pieces

Applications

• Fastening two or three layers of sheet metal panels and profiles together
• Roof and facade cladding: sheet + thick insulation + support profile installation
• Medium-gauge metal frames, suspended ceilings and support system connections
• Securing air-conditioning, ventilation duct and heavy pipe support brackets
• Metal doors, frames, fences and railing structures
• Manufacturing of machinery housings, thick-component white goods and electrical panels
• Interior partition systems and thick-profile fixture connections

Product Advantages

• No Pre-Drilling Required: Self-drilling tip penetrates sheet metal directly; noticeably reduces installation time and labour cost
• Wide Bearing Surface: YHB head spreads load over a large area; thin metals resist crushing and tearing, the washer profile assists sealing
• Deep Grip Length: 25 mm working length penetrates sufficiently deep into the support structure even in multi-layer builds such as sheet + insulation + sheet; ideal solution where 22 mm and shorter lengths are inadequate
• Well-Proportioned Pack: 12,000 pieces — enables long-running work without overstocking; simplifies storage and procurement
• Reliable Hold: Metal-optimised thread design resists loosening from vibration, wind load and temperature variation; connections remain secure for years
• Fast High-Volume Installation: Operates at high speed with electric screwdrivers; work proceeds efficiently even on large projects
• Long-Lasting Protection: Galvanized coating provides durable defence against moisture, rain and outdoor conditions

Installation Recommendations

• Position the screw perfectly perpendicular to the sheet surface; angled entry increases tip wear and reduces holding strength
• Best suited to total assembly thicknesses of 9–15 mm; ensure sufficient thread protrusion through the far side
• Do not over-tighten; stop when the head seats fully to prevent buckling the sheet
• Place a gasket between dissimilar metals; direct contact may cause galvanic corrosion
• Store in dry, well-ventilated conditions; prolonged damp exposure shortens coating life

Frequently Asked Questions

What does 3.9×25 mm mean and which thicknesses is it best suited for?
3.9 mm is the outer shank diameter; 25 mm is the effective length measured from beneath the head. It is ideal for multi-layer sheet, thick-insulated facade and heavy-duty metal assemblies with a total thickness of 9–15 mm.

How does the 25 mm length differ from shorter sizes?
The extra length passes through multiple layers in a single drive; engages deeper into the support profile, connections remain sag-free, load distribution is even, and loosening does not occur over time.

What makes the YHB head design different?
The flared head distributes pressure evenly; prevents tearing of the sheet, partially blocks moisture and rain ingress in outdoor applications, and delivers a clean, permanent finish.