Osg 10257005 Screw Machine Drill Bit 0.257in Cobalt Hss

Product Description

The OSG 10257005 is a screw machine length drill bit designed for high-performance drilling in steel and alloy steel applications. Built from cobalt high speed steel with a coated finish, this bit delivers increased heat and wear resistance compared to standard HSS tooling. It features a 130-degree split point with R-thinned web for easier penetration and reduced thrust. The straight-cylindrical shank seats securely in standard drill chucks. At 3.25 inches overall length with a 1.4375-inch flute, the stub-length geometry provides rigidity for accurate, on-center drilling in production and maintenance environments. This is a single-piece unit from OSG Series 1000, suited for machinists, tool-and-die techs, and industrial maintenance professionals.

This drill bit is intended for use in screw machine operations and general-purpose metal drilling where a short, rigid tool is preferred over jobber-length bits. It excels in drilling steel and alloy steel on drill presses, CNC lathes, turret lathes, and screw machines. The 3xD flute-to-diameter ratio and regular spiral keep chip evacuation clean in shorter-depth holes. The 0.257-inch diameter corresponds to Letter F sizing and 6.53 mm, making it a practical choice when matching drill charts for tapping or clearance holes in steel fabrication and machining work.

Key Features

• Cobalt high speed steel construction for improved heat resistance in steel and alloy steel drilling
• 130-degree drill point angle with R-thinned web for reduced thrust and self-centering entry
• Coated finish for added surface hardness and extended tool life
• Screw machine (stub) length provides extra rigidity and minimizes deflection
• Right-hand spiral flute with regular helix for consistent chip evacuation
• Straight-cylindrical shank fits standard drill chucks without adapters

Compatibility

Designed as a direct-fit screw machine length drill bit for use in standard drill chucks, turret lathes, and CNC drilling applications targeting steel and alloy steel workpieces. Diameter tolerance is plus 0 to minus 0.022 mm.

Installation Notes

Installation and use of this drill bit should be performed by machinists or qualified trade professionals familiar with rotating cutting tools. Ensure the machine spindle is fully stopped and locked out before inserting or removing the bit from the chuck. Verify chuck jaw condition and shank seating before operation. Follow applicable OSHA and machine-tool safety standards for speed, feed, and coolant selection based on workpiece material.