Hertel 66691494 Screw Machine Drill Bit 1/2 in Cobalt

Product Description

The HERTEL 66691494 is a screw machine length drill bit designed for heavy-duty drilling in metal, alloy steel, and other hard materials. Built from cobalt high-speed steel with a titanium nitride (TiN) coating, it offers superior wear resistance and heat tolerance compared to standard HSS bits. The 135-degree split point reduces walking on entry and requires less feed force at the start of a cut. At 3.75 inches overall length with a 2.25-inch flute, the shorter-than-jobber profile provides added rigidity, making it well-suited for drill press and CNC applications where chatter and deflection need to be minimized. This bit is installed and used by machinists, maintenance technicians, and metalworking trades.

Screw machine length drill bits are commonly used in production machining, maintenance and repair operations, and fabrication shops. The shorter overall length gives this bit better stiffness in turret lathes, drill presses, and machining centers. The straight cylindrical shank with 0.5-inch diameter seats directly in standard 3-jaw chucks and collet holders. Web thinning reduces thrust requirements, which is particularly useful when drilling stainless, tool steel, or titanium where heat buildup is a concern.

Key Features

• Cobalt high-speed steel construction for high-heat and abrasion resistance
• TiN coating extends tool life and reduces friction during cutting
• 135-degree split point for self-centering entry and reduced thrust
• Web-thinned parallel web configuration minimizes cutting force
• Screw machine (stub) length provides extra rigidity over jobber-length bits
• Right-hand spiral flute for efficient chip evacuation

Compatibility

Designed as a direct-fit replacement screw machine length drill bit for use in standard 3-jaw chucks, collet systems, and CNC tool holders accepting a 0.5-inch straight cylindrical shank.

Installation Notes

Always secure the workpiece and ensure the drill press or machine spindle is powered down and locked out before changing bits. Seat the straight shank fully in the chuck or collet and confirm it is centered before tightening. Use appropriate cutting fluid or coolant when drilling hard metals to extend tool life, as this bit does not support through-coolant delivery. Inspect the cutting edges before each use and replace if chipping or excessive wear is observed.