Hertel 66691486 Screw Machine Drill Bit 31/64 in Cobalt

Product Description

The HERTEL 66691486 is a screw machine length drill bit designed for high-performance metal drilling in demanding shop and field applications. Built from cobalt tool steel with a titanium nitride (TiN) coating, this bit handles harder workpiece materials where standard HSS bits fall short. The 135-degree split point reduces walking and allows the bit to engage the workpiece without a center punch in many setups. At 3-11/16 inches overall length with a 2-3/16 inch flute length, this is a stub-length format intended for rigid setups and close-quarter drilling where a jobber-length bit would flex or chatter.

This bit is suited for metalworking applications in machining, fabrication, and maintenance-repair-operations (MRO) environments. The 31/64 inch diameter (0.4844 inch decimal) fits within the 0.4500 to 0.5000 inch heavy-duty size range. The straight cylindrical shank seats directly in standard drill chucks and machine spindles without a reducer. Right-hand cutting direction is standard for conventional drill press, CNC, and hand-drill operation. Web-thinned geometry with a parallel web configuration reduces thrust requirements and improves chip evacuation in deep-hole applications.

Key Features

• Cobalt tool steel construction for heat resistance and extended tool life in hard or abrasive metals
• TiN coating reduces friction and improves wear resistance at the cutting edge
• 135-degree split point for reduced thrust and minimal walking on entry
• Web-thinned parallel web for improved chip flow and lower feed force
• Screw machine (stub) length provides added rigidity over jobber-length alternatives
• Straight cylindrical shank compatible with standard drill chucks and spindle toolholders

Compatibility

Designed as an OEM-style replacement or direct-use screw machine length drill bit for metalworking operations requiring a 31/64 inch diameter, straight-shank cobalt bit in heavy-duty drilling applications.

Installation Notes

Installation is performed by machinists, toolroom technicians, or maintenance professionals using a drill press, CNC machining center, or industrial hand drill. Secure the straight cylindrical shank fully into the chuck before operation and confirm runout is within acceptable limits for the application. Ensure the workpiece is clamped securely to prevent rotation or movement during drilling. Follow applicable shop safety procedures including eye protection and chip guarding when drilling ferrous or hardened materials.