STAINLESS STEEL HEXALOBULAR COUNTERSUNK AB SELF TAPPING SCREWS DIN 7982C

Hexalobular Countersunk AB Self Tapping Screws DIN 7982C — This screw brings the deep, positive engagement of a hexalobular recess to a flush-fitting countersunk head, making it a common specification wherever a production assembly needs both a tidy, flush finish and reliable, repeatable driving torque — panels, enclosures, and trim work in automotive and appliance manufacture, where cam-out on a cross-recess screw would mean stripped heads and stopped lines. The countersunk head seats into a matching chamfered clearance hole so the top sits level with the surrounding surface rather than standing proud, and shares its cone angle and thread-forming principle with the pan-head hexalobular equivalent, DIN 7981C — the head profile is the only real difference between the two. The AB point self-taps its own thread into thin sheet steel or aluminium as it's driven, generally self-starting without a pre-formed hole, though a pilot hole is still worth drilling wherever precise, repeatable location matters on a production line. As with DIN 7981C, this part describes DIN 7982's countersunk head and point geometry adapted to take a hexalobular recess, rather than following the dedicated international hexalobular standard, ISO 14586, covered separately in this range; the two are close cousins but dimensional interchangeability shouldn't be assumed without checking, so where a drawing specifies one standard, that's the one to follow. Grade selection is unchanged from elsewhere in the range: A2 stainless handles the great majority of general indoor and outdoor fixing work, while A4 is worth the extra cost on assemblies exposed to sustained chloride attack, such as coastal, marine, or washdown environments in food and chemical processing. Choosing a correctly sized hexalobular bit matters more here than with a cross recess, since a worn or mismatched bit will round the lobes rather than deliver the consistent torque this drive style exists to provide — and matching the clearance hole's countersink angle to the screw's actual head geometry is what keeps the finish genuinely flush rather than proud or sunk.

FAQs
Is DIN 7982C dimensionally interchangeable with ISO 14586?
Not automatically. The two are close in form, but ISO 14586 sets its own dimensions for the hexalobular format, so a drawing specifying one should not be filled with the other without checking.

What size hexalobular bit should be used?
One matched precisely to the screw's recess size; a worn or mismatched bit will round the lobes rather than deliver consistent torque.

How should the clearance hole be countersunk for a flush fit?
Match the countersink angle to the screw's actual head geometry so the top sits level with the surface, rather than proud or sunk.

Is A4 stainless available for coastal or washdown use?
Yes, for assemblies facing sustained chloride exposure in coastal, marine, or food and chemical washdown environments.