Osg 15339005 Cobalt Drill Bit Letter R 130 Degree

Product Description

The OSG 15339005 is a cobalt jobber length drill bit sized to Letter R (0.3390 inches / 8.61 mm), designed for high-performance drilling in steel and alloy steel. It carries a titanium nitride (TiN) coating that reduces friction and extends cutting life in demanding production environments. The 130-degree split point geometry promotes self-centering entry and reduces the thrust required to start a hole without a center punch. With an overall length of 5.25 inches and a flute length of 3.4375 inches, this bit fits standard drill chucks and CNC machining center spindles. It is installed and operated by machinists, tool-and-die technicians, and maintenance mechanics.

This bit is suited for drilling blind holes, cross holes, and through holes in ferrous workpiece materials including mild steel, alloy steel, and similar P-category metals. The straight-cylindrical shank diameter of 0.375 inches seats securely in standard Jacobs-style chucks and collet holders. The regular spiral flute configuration evacuates chips efficiently in both manual feed and power-feed drilling operations. Series 1500 tooling is positioned for high-performance general-purpose work where cobalt hardness and TiN coating extend tool life beyond standard high-speed steel alternatives.

Key Features

• Letter R diameter: 0.3390 inches (8.61 mm) with tolerance of +0 to -0.022 mm
• Cobalt substrate with titanium nitride (TiN) coating for extended wear resistance in ferrous materials
• 130-degree drill point with R-thinned web and tapered web configuration for reduced entry thrust
• Right-hand cut, regular spiral flute with 2 flutes for efficient chip evacuation
• Straight-cylindrical shank, 0.375 inches diameter, compatible with standard drill chucks and collets
• Tool applications include blind hole, cross hole, general drilling, and self-centering starts

Compatibility

Designed for use in steel and alloy steel workpieces (Primary Workpiece Material Code: P) across standard drilling operations. Fits any drill press, lathe tailstock, or machining center accepting a 0.375-inch straight shank. Coolant-through is not supported on this bit.

Installation Notes

Secure the shank fully in the chuck or collet before operating and verify runout is within acceptable limits for the application. De-energize and lock out the machine before changing tooling per standard OSHA lockout/tagout procedures. Apply cutting fluid appropriate for cobalt tooling in ferrous materials to maximize coating life and control heat buildup. Avoid exceeding the recommended surface footage for cobalt in hardened alloys to prevent premature edge wear.