Guhring 9006590063500 Cobalt Stub Drill Bit 0.25 Inch

Product Description

The GUHRING 9006590063500 is a cobalt screw machine length (stub) drill bit designed for high-performance drilling in hard and demanding workpiece materials. Built to DIN 1897 standards, this 0.25 inch diameter bit features a 130-degree split point, parabolic flute geometry, and a web-thinned construction that reduces thrust and improves chip evacuation. It is sized at 1/4 inch (decimal 0.2500 inch, letter size E) with a straight-cylindrical shank of 6.35 mm diameter. The stub length format provides added rigidity compared to jobber-length bits, making it well suited for production drilling environments where chatter and deflection must be minimized. Licensed HVAC, plumbing, and electrical trades as well as machining professionals install and use this bit in hand drills, drill presses, and CNC applications.

This bit is rated for use in titanium alloy as its primary workpiece material, which also makes it effective in stainless steel, high-temperature alloys, and other tough metals encountered in trade and industrial work. The parabolic flute design at a 3xD flute-to-diameter ratio allows efficient chip clearing at the 0.846 inch maximum drilling depth. The right-hand cutting direction is standard for conventional drill press and hand drill use. The Series 659 designation identifies it within the GUHRING cobalt heavy-duty stub drill product line, indicating it is built for repeated use in demanding production cycles where standard HSS bits fail prematurely.

Key Features

• Cobalt tool material rated for heavy-duty drilling in titanium alloy and hard metals
• 130-degree drill point angle with standard point type for positive engagement and reduced walking
• Parabolic flute geometry promotes efficient chip evacuation and reduced heat buildup
• Web-thinned, parallel web construction lowers axial thrust during entry
• Stub length (DIN 1897) format increases rigidity and reduces deflection in tight clearance applications
• Diameter tolerance of +0.000 to -0.022 mm ensures precise hole sizing

Compatibility

Designed as an OEM-style heavy-duty stub drill replacement conforming to DIN 1897 specifications, suitable for use in standard straight-shank drill chucks across hand drills, drill presses, and CNC drilling equipment accepting a 6.35 mm straight-cylindrical shank.

Installation Notes

Install into a properly sized drill chuck and verify shank seating before operation. Power down or de-energize all equipment before changing bits. Use appropriate cutting fluid or coolant when drilling titanium alloy or stainless steel to extend tool life, noting that this bit does not have through-coolant capability. Follow applicable OSHA and shop-safety guidelines for rotating tool operation, including eye protection and secure workpiece fixturing.