STAINLESS STEEL SLOT RAISED COUNTERSUNK AB SELF TAPPING SCREWS DIN 7973C

Slot Raised Countersunk AB Self Tapping Screws DIN 7973C — DIN 7973C combines the flush-seating base of a countersunk head with a domed top left visible above the surface, giving a more finished, rounded appearance than a flat countersunk screw while keeping the same single straight slot found throughout the slotted range. It's most often specified where the fixing needs to look deliberate rather than purely functional — furniture hardware, decorative trim, and restoration or period-matching work, sometimes finished off with a cup washer to frame the domed head — and less often where driving speed or automated assembly matters, since a slot recess gives the driver bit no self-centring help and comparatively little resistance to cam-out compared with a cross, star, or square recess. The AB point shared with the rest of this range self-taps its own thread as it's driven into thin sheet steel or similar gauge material, generally without needing a pre-formed hole, although a pilot hole is still sensible for accurate location, particularly given how readily a slot driver can slip on a hard or painted surface. Functionally, DIN 7973C behaves exactly like the plain countersunk DIN 7972C at the seating face — the same countersink angle, the same thread-forming action — the raised dome changes only what's visible once the screw is fully driven. Grade selection is unchanged from the rest of the range: A2 stainless is the sensible default for general indoor and outdoor use, while A4 is worth specifying wherever the fixing will be visible and exposed to coastal air, marine conditions, or repeated washdown, since staining or light corrosion on a decorative head is more noticeable than the same wear on a hidden fixing. As with any countersunk profile, matching the clearance hole's countersink to the screw's actual head angle is what determines whether the finished dome sits at the intended height rather than proud or sunk.

FAQs
Is a cup washer commonly used with this screw?
It's a common cosmetic pairing to frame the domed head, but not a functional requirement of the fixing itself.

Does the raised dome affect how flush the screw sits?
No. The base of the head seats in the countersink exactly as a plain countersunk screw does; the dome only affects what's visible above the surface.

What flat-blade driver size should be used?
One with a blade width closely matched to the slot, so it bears fully across the recess rather than slipping under load.

Is this screw available in A4 for exposed decorative fixings?
Yes, A4 (316-equivalent) is worth specifying where a visible fixing faces coastal air, marine conditions, or repeated washdown.