The OSG Metric Spiral Flute Threading Tap is a high-performance tool designed for precise threading in blind holes, ideal for professional machinists and shops handling large-diameter metric threads. Crafted from HSS-E with cobalt and finished in steam oxide, it delivers durable cutting performance and excellent heat resistance in demanding tasks.

• Size/Thread: M39 x 4 — large-diameter metric thread for blind-hole applications.
• Flute Design: Spiral flute geometry optimized for efficient chip evacuation and reduced clogging.
• Material: High-Speed Steel with cobalt (HSS‑E) for enhanced hardness and wear resistance at elevated temperatures.
• Coating: Steam oxide coating to lower friction and improve heat dissipation during cutting.
• Application: Specifically suited for threading blind holes with clean, accurate thread formation.
• Technology: OSG’s advanced threading technology provides consistent results and reliable tool life in demanding environments.

This tap delivers reproducible, high-quality threads with fewer passes and less risk of tool chatter or breakage. The spiral flute design accelerates chip removal from blind holes, reducing heat buildup and extending tool life. Combined with the cobalt-infused HSS and steam oxide coating, it maintains a sharp cutting edge for longer, ensuring precise threads and improved finish across challenging materials. A dependable choice for critical assemblies, mold work, and maintenance tasks where precision and durability matter.