Osg 6156911 Screw Machine Drill Bit Letter I Tialn Hss

Product Description

The OSG 6156911 is a screw machine length drill bit sized to Letter I (0.2720 inch / 6.91 mm) and designed for high-performance drilling in steel, stainless steel, aluminum, and other non-ferrous materials. Built from vanadium high-speed steel and finished with a TiAlN coating, the bit runs a 120-degree, 4-facet point with web thinning to reduce entry force and improve chip evacuation. Overall length is 3.0709 inches (78.00 mm) with a 34.00 mm flute length and a straight cylindrical shank of 8.00 mm (0.3150 inch) diameter. The compact screw machine length makes it well suited for CNC machining centers, turret lathes, and other setups with limited tool clearance.

This drill is intended for production and job-shop environments where consistent hole quality and tool life in demanding workpiece materials are required. The 5xD flute-to-diameter ratio and tapered web configuration support reliable chip flow in interrupted or deep-entry passes. It is appropriate for machinists and toolroom professionals working with ferrous and non-ferrous stock, particularly in applications where a standard jobber-length drill would be too long or insufficiently rigid. The right-hand, regular spiral flute geometry suits standard spindle rotation on conventional and CNC machine tools.

Key Features

• Letter I size: 0.2720 inch (6.91 mm) diameter with a tolerance of +0 to -0.022 mm
• TiAlN coating extends tool life in steel and stainless steel applications
• 120-degree, 4-facet point with web thinning reduces thrust and improves centering
• Vanadium high-speed steel construction for toughness in high-performance cutting
• Screw machine (stub) length at 3.0709 inches OAL increases rigidity over jobber-length designs
• Straight cylindrical shank (8.00 mm) fits standard drill chucks and collet holders

Compatibility

Designed as an OEM-style replacement or direct-use cutting tool for machine setups requiring a Letter I screw machine length drill bit with a straight shank. Suitable for use in drill chucks and collet systems accepting an 8.00 mm straight shank. Primary workpiece materials include steel, stainless steel, aluminum, and non-ferrous alloys per OSG Series 1100 specifications.

Installation Notes

Installation should be performed by a qualified machinist following standard toolroom practices. Secure the shank fully in a properly sized chuck or collet and verify runout before engaging the workpiece. Ensure the machine spindle is fully stopped and locked out before inserting or removing the bit. Do not exceed the tool manufacturer's recommended feeds and speeds for the workpiece material and coating type.