If securing ductboard to a metal, what screw should you use?

If securing ductboard to a metal, what screw should you use?

• A. #8 wood screws with hex nuts
• B. Nails and washers
• C. Machine screws with lock washers
• D. #10 sheet metal screws along with 2 1/2 square washer

Answer: (D)

Attaching ductboard to metal calls for fasteners that can bite into metal while not crushing the softer ductboard, and that also spread the clamping force so the board isn’t torn or pulled through. Self-tapping sheet metal screws are designed for this job; they create their own threads in the metal as you tighten, giving a secure hold without needing nuts or predrilled holes. Using a washer under the screw head distributes the load over a larger bearing surface, which protects the ductboard from damage and helps prevent pull-through under vibration or pressure. That’s why the combination of sheet metal screws with a washer is the practical, reliable choice for this connection. Other fasteners don’t fit as well: wood screws are meant for wood and won’t form proper threads in metal; nails don’t provide the required pull-out resistance; machine screws with lock washers require matching tapped holes or nuts and add unnecessary complexity for attaching ductboard to a metal frame.

Attaching ductboard to metal calls for fasteners that can bite into metal while not crushing the softer ductboard, and that also spread the clamping force so the board isn’t torn or pulled through. Self-tapping sheet metal screws are designed for this job; they create their own threads in the metal as you tighten, giving a secure hold without needing nuts or predrilled holes. Using a washer under the screw head distributes the load over a larger bearing surface, which protects the ductboard from damage and helps prevent pull-through under vibration or pressure.

That’s why the combination of sheet metal screws with a washer is the practical, reliable choice for this connection. Other fasteners don’t fit as well: wood screws are meant for wood and won’t form proper threads in metal; nails don’t provide the required pull-out resistance; machine screws with lock washers require matching tapped holes or nuts and add unnecessary complexity for attaching ductboard to a metal frame.