Guhring 9038990006400 Micro Drill Bit Size 72 Solid Carbide

Product Description

The GUHRING 9038990006400 is a solid carbide micro drill bit sized at wire gauge 72 (0.0252 inches decimal), designed for precision drilling in demanding industrial and machining environments. Built from K40-grade solid carbide and coated with TiAlN for heat resistance and extended tool life, this bit delivers consistent performance in tight-tolerance applications. It features a 140-degree faceted point with web thinning to reduce thrust and improve centering at entry. The spiral flute design with a 5xD flute-to-diameter ratio promotes chip evacuation in shallow holes. Overall length is 38 mm with a 3 mm straight-cylindrical shank sized to an h7 tolerance for accurate chuck fitment. Installed by machinists and tool-and-die professionals on CNC and manual drilling equipment.

This micro drill bit is suited for precision drilling in cast iron and steel workpieces where small-diameter, close-tolerance holes are required. The 140-degree point angle is well matched to harder ferrous materials, reducing walking and improving entry accuracy. With a maximum drilling depth of 6.04 mm (0.2380 inches) and a flute length of 7.00 mm, it is intended for shallow through-holes and blind holes in production and prototype machining. The straight-cylindrical shank fits standard collet chucks and drill chucks compatible with 3 mm shank tooling. Part of the Guhring Series 3899 micro drill family.

Key Features

• K40-grade solid carbide construction for rigidity and wear resistance in ferrous materials
• TiAlN coating improves heat resistance and extends tool life in steel and cast iron
• 140-degree faceted point with web thinning reduces thrust and improves entry accuracy
• Spiral flute with 5xD ratio promotes consistent chip evacuation in shallow holes
• h7 shank diameter tolerance ensures accurate, repeatable chuck registration
• Right-hand cut, regular spiral type for standard CNC and manual drilling setups

Compatibility

Designed for use with standard collet chucks or drill chucks accepting a 3 mm straight-cylindrical shank. Primary workpiece materials are cast iron (material code K) and steel (material code P) as specified by the manufacturer for the Series 3899.

Installation Notes

Micro drill bits of this diameter require a rigid, well-trammed spindle setup to prevent deflection and breakage. Secure the shank fully in a precision collet or drill chuck before operation, and confirm runout is within tolerance for the application. Reduce feed rates and spindle speeds incrementally when dialing in a new setup with carbide micro tooling. Avoid side loading the bit during entry or retraction, as solid carbide at this diameter is brittle under lateral force.