The Ultimate Fasteners M2M Metal to Metal screw is the perfect option for getting through that heavy gauge steel! Great for metal joists and any job where metal to metal joinery is needed! It’s advanced Tek, Quadrex drive & superior strength make this screw a sure win! Use a #2 square. 16 threads per inch. • # 3 Point • Drilling capacity 0.110 (12 gauge) – 0.179 (7 gauge).