5/8"-18 × 4" Grade 8 Indented Hex Flange Screw – Zinc Yellow CR+6, Baked (Non‑Serrated, Fine Thread)

Designed for high‑strength structural and automotive applications, the 5/8"-18 × 4" fine‑thread Grade 8 indented hex flange screw is commonly specified for frame and chassis assemblies requiring higher clamping force and improved resistance to vibration. The integrated non‑serrated flange provides wide, even load distribution while protecting mating surfaces, eliminating the need for a separate washer. Manufactured from high‑strength alloy steel, this fastener features a zinc yellow CR+6 finish for enhanced corrosion resistance. A post‑plating bake process helps reduce the risk of hydrogen embrittlement, ensuring reliable performance in demanding, high‑stress environments.