Guhring 9003290128000 Cobalt Stub Drill Bit 12.80 Mm

Product Description

The GUHRING 9003290128000 is a cobalt (M35 grade) stub-length drill bit with a 12.80 mm diameter and a 130-degree split point designed for demanding metal-cutting applications. Built to DIN 1897 standards, it features a web-thinned, tapered-web geometry that reduces thrust and improves chip evacuation. The spiral flute configuration and oxide finish contribute to heat resistance and extended tool life in tough materials. With an overall length of 4.016 inches and a flute length of 2.008 inches, this bit is suited for precision drilling in short-reach setups. Machinists and tool-room technicians working on production lines or job shops will find this a reliable choice for close-tolerance hole-making.

This drill bit is engineered primarily for titanium alloy workpieces and other hard-to-machine materials where standard high-speed steel bits fall short. The stub length and straight cylindrical shank allow use in standard drill chucks, CNC machining centers, and screw machine applications where rigidity and minimal runout are critical. It is dimensioned per DIN 1897 and falls within the 11.00 mm to 13.50 mm diameter size range of the Series 329 family, making it appropriate for applications requiring a nominal half-inch class bore.

Key Features

• M35 cobalt steel construction for high-heat and work-hardened material performance
• 130-degree point angle with web thinning reduces entry thrust and improves centering
• Stub (screw machine) length for maximum rigidity in short-reach setups
• Oxide surface finish improves lubricity and corrosion resistance during cutting
• Right-hand spiral flute promotes efficient chip evacuation
• Manufactured to DIN 1897 dimensional standard for predictable fit in tooling systems

Compatibility

Designed as an OEM-style replacement or direct tooling selection within the GUHRING Series 329 stub drill family, fitting any standard drill chuck or collet accepting a 12.80 mm straight cylindrical shank.

Installation Notes

Installation and use should be performed by qualified machinists familiar with metal-cutting tooling practices. Ensure the machine spindle is fully stopped and de-energized before inserting or removing the bit from the chuck or collet. Apply appropriate cutting fluid or coolant at the workpiece to manage heat, particularly when drilling titanium alloys. Confirm shank seating depth and runout with a dial indicator before starting production cuts to stay within the listed diameter tolerance of plus 0.000 to minus 0.027 mm.