5.5x45mm CSK S/Drill Screws Fi ne Thread For Heavy Steel (Zin

This range of self-drilling screws can vastly speed up assembly and installation times in sheet metalwork, ducting manufacture, electrical installations and general construction.
This roofing and general construction range has been specifically designed and manufactured to meet all the recognised industry standards and performance criteria.

• To obtain MaxCT (appropriate maximum clamping thickness):
• Washered Screws: Take the drill tip + thread engagment (5mm) + washer thickness (3mm) and subtract from total length of screw. 
• Non Washered Screw: Take the drill tip + thread engagment (5mm) and subtract from total length of screw