Self-Drilling vs Self-Tapping Screws: How to Choose

Self-drilling and self-tapping screws both cut their own thread, but they start very differently, and choosing wrong slows a crew down all day.

Self-drilling screws

A self-drilling screw has a drill-bit point that bores its own pilot hole as it goes. No pre-drilling needed, drive it straight into steel purlins, sheet metal or thin plate in one action. This is the screw roofing and cladding crews live on.

Self-tapping screws

A self-tapping screw cuts a thread into an existing hole. You (or a pre-punched panel) provide the pilot hole; the screw taps its mating thread as it drives. Ideal for thicker material, plastics, and situations where the hole is already there.

Heads, grades and sizes

Both come in PAN and CSK heads, and in GI, SS 304 and SS 316. For anything outdoors or coastal, step up to stainless. We stock hex-head self-drilling screws and the full PAN/CSK self-tapping range in all sizes, carton pricing for contractors.