10-24 x 1-1/4 Elco Dril-Flex / Phillips / Wafer Head / Steel / Stalgard / QTY 5000 Uses 3/16 in and 1/4

Uses 3/16 in and 1/4 in tappers

Better yet

8-15X2 1/4 Phillips Bugle Head Fine Thread Drywall Screw Black Phosphate

have a large flanged head

Bi-Flex structural screws are bi-metal self-drilling tapping screws that provide the corrosion resistance of 300 series stainless steel and the efficiency of drill screws

10-24 x 1-1/4 Elco Dril-Flex / Phillips / Wafer Head / Steel / Stalgard / QTY 5000 Uses 3/16 in and 1/4Dril Flex Structural Screws are dual heat treated self drilling tapping screws that provide the strength, ductility and resistance to embrittlement required for critical applications. Features & Specs High hardness point and lead threads for drilling and tapping Stalgard and Stalgard SUB Coatings provide improved corrosion resistance as well as enhanced galvanic compatibility in dissimilar metal applications, including those involving aluminum,