Guhring 9003290085000 Cobalt Stub Drill Bit 8.50mm

Product Description

The GUHRING 9003290085000 is a cobalt (M35 material grade) stub-length drill bit designed for high-performance drilling in demanding materials. Built to DIN 1897 standards, it features an 8.50 mm diameter with a 130-degree split point and a web-thinned, tapered web configuration that reduces thrust and improves chip evacuation. The oxide-coated flutes are spiral-type with a regular helix, and the straight-cylindrical shank provides secure chuck retention. With an overall length of 3.1102 inches (79 mm) and a flute length of 1.4567 inches (37 mm), this bit is sized for short-reach, high-precision applications where rigidity matters. Licensed machinists and tooling specialists are the primary users of this bit in production environments.

This drill bit is rated for primary use in titanium alloy workpieces, making it well-suited for aerospace, medical device, and precision machining applications where work-hardening materials demand cobalt-grade tooling. The stub-length format reduces deflection and improves hole location accuracy in CNC machining centers, drill presses, and manual machine tool setups. The 3xD flute-to-diameter ratio supports controlled chip removal at depths up to 1.4567 inches (37 mm). Series 329 from GUHRING is a purpose-built stub drill line for tough, short-reach drilling tasks in production environments.

Key Features

• Cobalt M35 construction for elevated heat resistance and tool life in titanium alloy and hard metals
• 130-degree point angle reduces thrust and improves self-centering on hard materials
• Web-thinned tapered web configuration lowers entry force and chip packing risk
• Oxide finish coating provides lubricity and corrosion resistance during dry and semi-dry cutting
• DIN 1897 stub-length format delivers maximum rigidity and minimal runout
• Straight-cylindrical shank with 8.50 mm diameter compatible with standard drill chucks and collet systems

Compatibility

Designed as a DIN 1897 stub-length drill bit for use in CNC machining centers, drill presses, and manual machine tools equipped with standard collet or chuck systems accepting an 8.50 mm straight-cylindrical shank. Primary workpiece material is titanium alloy; cobalt construction also supports use in other hard and work-hardening metals.

Installation Notes

Installation and use should be performed by qualified machinists or tooling technicians familiar with drill press and CNC machine operation. Ensure the machine spindle and chuck or collet are fully de-energized and at rest before inserting or removing the bit. Verify chuck or collet bore matches the 8.50 mm shank diameter to prevent slippage and runout. Do not exceed the maximum drilling depth of 1.4567 inches (37 mm) in a single pass without retracting to clear chips.