Bi-Metal Wafer Head Self-Drilling Screws for Steel and Solar Mounting
The bi-metal wafer head self-drilling screw combines a low-profile 304 stainless flange head with a hardened carbon steel drill point. It drills into steel without pre-drilling, and the wide wafer head spreads the load across thin sheet for a flush, neat finish. A favorite for steel framing, cladding and solar mounting systems where stainless appearance and drilling capability must coexist.
Features and Benefits
- Low-profile wafer head sits almost flush on thin sheet — no snag, clean architectural line
- 304 stainless head resists corrosion and staining at the exposed face
- Hardened drill point fastens steel up to 2.5 mm in a single operation
- Wide flange replaces a separate washer on most thin-sheet applications
- Phillips and Torx drive options matched to high-volume installation tooling
Typical Applications
- Solar panel rails and clamps to steel purlins
- Steel framing, furring and hat channel assembly
- Metal cladding and rain-screen substructures
- Stainless-to-steel connections in roofing trim
- Appliance and equipment enclosures
Model Specifications
| Thread Size | Drilling Capacity | Length Range | Drive | Head |
|---|---|---|---|---|
| 5.5 mm (#10) | steel up to 2.0 mm | 13-50 mm | PH2 / T20 | Wafer 10-11 mm |
| 6.3 mm (#12) | steel up to 2.5 mm | 16-65 mm | PH3 / T25 | Wafer 11-12 mm |
Material and Performance
- Head and shank: AISI 304 stainless steel, passivated
- Drill point: hardened alloy steel, friction or laser welded, weld torque tested per batch
- Flange diameter 10-12 mm distributes clamp load on sheet from 0.5 mm
- Standards: DIN 7504 N equivalent geometry; ISO 9001 factory quality system
Installation Guidelines
- Match the drill point to total steel thickness — the point must clear the stack before the thread starts pulling.
- Drive square to the surface so the wafer head seats evenly without tilting.
- Stop when the flange contacts the sheet; overdriving spins the point and destroys the hole.
- For stacked sheets with gaps, verify the combined thickness against drilling capacity before the run.
- Use depth-setting nosepieces on production lines for consistent seating across crews.
Why Source from BuildFastener
Batch-tested welds, drill capacity and drive torque back every shipment. Solar programs benefit from our kitting service — rails, screws and accessories packed per installation. Request samples for your tooling trial.
Need this product for your project?
Request a Quote for This Product
