S-90420A667 1/4"-20 x 4" Tapping Screws

Key Features & Benefits at a Glance

• Eliminates pre-drilling requirements with its integrated drilling tip, cutting labor time and tooling costs in steel, stainless steel, and sheet metal applications.
• Superior corrosion resistance is ensured by the 18-8 Stainless Steel base material with a Galvanic-Barrier Coating, extending service life in demanding environments.
• High-strength thread forming (CSD) action creates strong, wear-resistant threads in the parent material for a secure, vibration-resistant hold.
• Effortless installation and high torque capability are provided by the External Hex Drive and robust 3/8" Hex Head, compatible with standard tools.
• Enhanced load distribution and seating are achieved with the integrated Flange design, helping to prevent loosening under stress.
• Reliable performance in coarse-thread applications is delivered by the 1/4"-20 UNC right-hand thread, ideal for quick assembly in various materials.
• Optimized for materials up to 0.21" thick, the No. 3 drill tip and specific tip length enable efficient penetration in specified metal gauges.

Professional Applications & Engineering Value

This 1/4"-20 UNC tapping screw is engineered to solve critical assembly challenges in metalworking and fabrication. Its thread-forming design eliminates the need for a separate tapping operation and the risk of chip accumulation, creating clean, strong threads directly in steel, stainless steel, and sheet metal. The galvanic-barrier coated 18-8 stainless steel construction is vital for preventing galvanic corrosion when fastened to dissimilar metals, a common pain point in mixed-material assemblies. The combination of a drilling tip and partial threading allows the screw to drill, tap, and fasten in a single operation, dramatically reducing installation time and labor costs while ensuring a secure, reliable connection that stands up to vibration and stress.

Specification Summary & Compliance

This screw conforms to UNC coarse thread standards (1/4"-20) with a right-hand thread direction. It is manufactured as a CSD Type thread-forming tapping screw. The 18-8 Stainless Steel material and specific coatings are compliant with common industry regulations such as RoHS and REACH. The dimensional specifications, including the 4" length, 3/8" hex head width, and 0.52" flange diameter, are precision-manufactured to ensure consistent performance and interchangeability.