Hertel 66693607 Screw Machine Drill Bit Letter W Hss

Product Description

The HERTEL 66693607 is a screw machine length drill bit designed for high-production drilling in metal, steel, and other ferrous and non-ferrous materials. It carries a Letter W designation, which corresponds to a decimal diameter of 0.3860 inches, and is manufactured from high-speed steel with a titanium nitride (TiN) coating that extends cutting edge life by reducing friction and heat buildup. The 135-degree split point allows the bit to start on contact without a center punch, reducing walkout on flat surfaces. This bit is intended for use by machinists, tool-and-die tradespeople, and maintenance mechanics working in production or job-shop environments.

Screw machine length drill bits are shorter than jobber-length bits, which provides greater rigidity and reduces deflection during drilling. This makes the 66693607 well suited for CNC machining centers, manual drill presses, and screw machines where controlled depth and positional accuracy matter. The straight-cylindrical shank accepts standard three-jaw chucks across a wide range of machine spindles. The heavy-duty grade designation indicates the bit is built for demanding cycle rates and harder workpiece materials within its size range of 0.3500 to 0.4000 inches.

Key Features

• Letter W size at 0.3860 inches decimal diameter for precise hole dimensioning
• 135-degree split point with web thinning reduces thrust and eliminates center-punch requirements
• TiN coating improves wear resistance and extends tool life in repetitive drilling cycles
• High-speed steel construction handles a broad range of metals and alloys
• Screw machine length body provides added rigidity over jobber-length alternatives
• Straight-cylindrical shank fits standard three-jaw chucks without adapters

Compatibility

Designed as a direct-fit replacement or add-to-stock drill bit for any machine spindle or chuck accepting a 0.3860-inch straight-cylindrical shank in the 0.3500 to 0.4000-inch drill bit size range.

Installation Notes

Installation is performed by machinists or maintenance mechanics using a standard three-jaw chuck or collet system. Ensure the machine spindle is fully powered down and the chuck key is removed before inserting or changing the bit. Verify chuck runout and shank seating before initiating a cut. Coolant-through is not supported on this bit, so external coolant or cutting fluid should be applied at the work surface when drilling at high cycle rates or in harder materials.