Osg 2916608 Spiral Flute Tap 4-40 Unc Ticn Vanadium Hss

Product Description

The OSG 2916608 is a spiral flute tap designed for cutting internal 4-40 UNC threads in a wide range of ferrous materials. Built from vanadium high-speed steel and finished with a titanium carbonitride (TiCN) coating, it delivers extended tool life in demanding production and job-shop environments. The modified bottoming chamfer allows threading close to the bottom of a blind hole. With a 45-degree helix angle and right-hand flute direction, the tap efficiently evacuates chips upward out of the hole, reducing the risk of chip packing in interrupted or deep-hole applications. Machinists and tool-and-die technicians are the primary users.

This tap is suited for threading 4-40 UNC holes in alloy steel, carbon steel, cast iron, stainless steel, die steel, and hardened steel. The modified bottoming chamfer makes it well-suited for blind-hole work where thread engagement close to the hole bottom is required. The TiCN coating adds surface hardness and lubricity, making it a practical choice for stainless steel and harder alloy grades where uncoated HSS taps wear quickly. It is used in manual tapping, CNC machining centers, and dedicated tapping machines.

Key Features

• 4-40 UNC right-hand thread form with H5 thread limit for close-tolerance fits
• TiCN coating increases surface hardness and reduces friction against difficult materials
• 45-degree spiral flute helix lifts chips out of blind holes, preventing re-cutting
• Modified bottoming chamfer enables threading near the base of blind holes
• Vanadium high-speed steel base material resists heat and wear in steel and cast iron
• Oversize designation accommodates coating buildup to maintain thread tolerance

Compatibility

Designed for cutting 4-40 UNC internal threads in alloy steel, carbon steel, cast iron, stainless steel, die steel, and hardened steel workpieces across manual and machine tapping applications.

Installation Notes

A licensed machinist or toolroom technician should verify correct tap drill size and hole depth before use. Secure the workpiece and ensure the tap is aligned perpendicular to the hole to prevent tap breakage, especially in harder materials. Use a compatible tapping fluid or cutting oil appropriate for the workpiece material. Inspect the tap for wear or chipping before each use, as a damaged tap in hardened steel can break and require EDM extraction.