Self-drilling Sheet Metal Screw Koelner B-SL-FS-3545, phosphate-coated, 3.5×45 mm, container pack

Koelner self-drilling sheet metal screw B-SL-FS-3545 is a phosphate-coated fastening solution sized 3.5×45 mm supplied in a container pack. The screw features an integrated self-drilling tip that allows fastening thin sheet metal directly to metal substrates without the need for pre-drilling. The phosphate coating improves surface hardness and offers basic corrosion resistance suitable for indoor and covered outdoor applications. This fastener is intended for professional and DIY use where reliable metal-to-metal connections are required.

Advantages

The self-drilling tip eliminates the time and effort of pre-drilling, speeding up installation. The 3.5×45 mm dimensions provide sufficient length and penetration for thin sheets and common metal backing while maintaining a low profile. Phosphate coating enhances thread durability and provides moderate protection against rust in non-aggressive environments. Supplied in a container pack, the screws are easy to store and handle on-site.

Suitable for

• Fastening thin sheet metal to steel or aluminum substrates
• Roofing repair and installation where self-drilling fasteners are required
• HVAC ductwork assembly and mounting
• Light metal fabrication and panel attachment

Key specifications

• Size: 3.5 × 45 mm (diameter × length)
• Head type: compatible with standard cross or Torx drive (check product head marking)
• Tip: integrated self-drilling point for direct metal-to-metal fastening
• Surface finish: phosphate coating for improved surface hardness and basic corrosion resistance
• Pack type: container pack for bulk storage and on-site use

How to use

Select the appropriate screw length and drive bit for the head type. Position the sheet metal on the substrate and apply steady pressure while driving the screw with an electric screwdriver or drill at moderate speed. Allow the self-drilling tip to cut through the sheet and into the substrate; do not apply excessive speed or force to avoid deforming the sheet. For best results, maintain perpendicular alignment between the screw and the sheet surface during installation.

Usage recommendations

Use these phosphate-coated self-drilling screws in dry or covered environments and avoid prolonged exposure to highly corrosive conditions. For outdoor or marine-exposed applications, consider stainless or zinc-coated alternatives. Pre-fit panels and test-drive a screw in a spare area to confirm fit and drive settings before full installation.