OSG Threading Tap - UNF Spiral Flute HSS-E - Steam Oxide Coated - Blind Hole - 1/4 x 28

The OSG UNF Spiral Flute Threading Tap is a precision tapping tool designed for blind-hole work, delivering clean, accurate 1/4-28 UNF threads with every pass. Built for professional machinists, it emphasizes durability and consistent results in challenging materials.

• Material: HSS‑E cobalt substrate for superior wear resistance and heat tolerance during deep internal threading.
• Coating: Steam oxide coating reduces friction and protects against corrosion for extended tool life.
• Tool geometry: Spiral flute design enhances chip evacuation, preventing built-up material in blind holes.
• Thread format: UNF threading, 1/4-28, optimized for high-precision internal threads.
• Application: Ideal for blind-hole applications in tougher metals where consistent start and finish matter.
• Durability: Engineered for long tool life and repeatable results in demanding machining tasks.

This tap's HSS‑E cobalt core, combined with a steam oxide finish, provides robust heat resistance and low-friction cutting, extending tool life and reducing downtime. The spiral flute design ensures efficient chip evacuation, which is crucial when threading blind holes and helps maintain thread geometry and surface finish. With 1/4-28 UNF threads, it integrates smoothly with standard fasteners and components, making it a reliable choice for precision assemblies, maintenance, and production runs. In practice, users can expect repeatable thread depth, fewer reworks, and a cleaner internal thread surface even in materials that challenge ordinary taps.