Metallics RSDS7B 9 x 3-1/2 in. Bugle Head Star Drive Deck Screws - Steel Yellow Zinc - Type 17 - Threads - Each

A T25 bit. The RSDS7B uses a star (flat six-lobe) recess, so a T25 star/Torx driver seats fully and keeps you from camming out when you're sinking 3-1/2 inch screws into dense framing.

No. The RSDS7B has a Type 17 point, which carries a chip cavity (auger point) that lets the fastener drive without pre-drilling a pilot hole, including in denser woods. On brittle hardwood trim or close to a board end you may still want to pre-drill to avoid splitting.

Yes. At 3-1/2 inches of length a #9 screw passes through nominal 2x decking (1-1/2 in. actual) and still buries roughly 2 inches of thread in the joist. The deeper thread form on the RSDS series is there specifically to resist pull-out, and the bugle head pulls flush into softwood without a washer.

The RSDS7B is carbon steel with a yellow zinc dichromate finish. That coating is a light corrosion barrier suited to general interior and protected exterior wood work. For direct, sustained weather exposure or contact with modern ACQ/copper-treated lumber, specify a stainless or heavy polymer-coated deck screw instead, since a zinc dichromate plating is not an equivalent to those systems.

They ship as a 440-count box, which is also the order minimum. Plan quantity in whole boxes rather than per piece.

It self-countersinks in wood. The bugle head measures 0.316 to 0.358 in. across and 0.124 in. high, so the tapered underside draws itself flush into softwood decking without a separate counterbore. Keep head width in mind if you're driving into a pre-drilled metal or composite part with a fixed hole size.

The RSDS7B is flagged both ARRA compliant and Buy American compliant in the manufacturer's data, which is what procurement on federally funded work usually asks for. Country of origin is listed as multiple, so if your specification requires a single documented origin, request the mill documentation for the lot you are buying.

AISI 1018 to 1022 low-carbon steel, with a yellow zinc dichromate plating. That is the standard case-hardenable wire for wood screws: hard enough at the Type 17 point to cut its own hole, with enough body ductility to take driving torque from a T25 bit.

It is a #9 diameter screw, 3-1/2 inches long, with a UNC coarse thread form at 9 threads per inch. Coarse pitch is what you want in wood: fewer, deeper threads grip fiber instead of shearing it. Note the manufacturer states that with no single industry standard for deck screws, slight dimensional deviation is acceptable.

The 440-count box comes in at 7.48 lbs, with the carton measuring 7.25 x 6.25 x 6 in. Useful if you are palletizing a multi-box order or estimating freight on a large deck package.