eBay

#10 x 1-5/8" Reamer Tek Screws - They are used in softwood or hardwood and these deep, wide and sharp threads provide maximum holding power (no pre-drilling in most applications).
Trailer Deck Screws - Manufactured from high quality heat treated steel. Coated with the bronze star triple ceramic coating for superior exterior protection.
Reamer Tek Screws - ACQ pressure treated lumber compatible and corrosion resistant. Self-Drilling wings bore through wood and then break off once they contact the steel or aluminum.
The screws use torx/star drive T-25. torx/star drive delivers twice the torque of phillips or square drive tek screws.
#10 x 1-5/8" reamer tek screws manufactured by TNITRIB after 1200 Hours of salt spray testing without failures.

#10 x 1-5/8" Reamer Tek Torx/Star Head Self-Drilling Wood to Metal Screws - Tek Screws for Flatbeds, Trailers, or for Fastening Wood to Steel - T-25 Torx Screw Head (130 Pcs)
Maximum Wood depth ~7/8" - Maximum Metal Thickness Screw Can Bore ~1/8" - Use T-25 Torx/Star Bit.
Dimensions: Head Width .38" - Total Length 1-5/8" - Shank Diameter .19" - Torx /Star Bit Not included.
They are designed for trailer decks, truck beds, docks, horse trailers, utility trailers, ATV trailers, etc.
Note：Keeping the speed low and not pushing too hard was super important.