Hertel 66691841 Cobalt Screw Machine Drill Bit Size 8

Product Description

The HERTEL 66691841 is a cobalt screw machine length drill bit designed for high-performance drilling in tough materials. Built to a wire gauge size 8 (0.1990 inches), it features a 135-degree split point that reduces walking and allows fast penetration without a center punch. The TiN (titanium nitride) coating extends tool life by reducing friction and heat buildup at the cutting edge. At 2.25 inches overall length, this stub-length bit provides rigidity and accuracy in short-reach drilling applications. It is suited for machinists, maintenance technicians, and metalworking tradespeople working with steel, stainless, and other ferrous metals where standard HSS bits lose their edge prematurely.

This bit is appropriate for use in drill presses, CNC machining centers, and hand-held power drills in both production and job-site environments. The screw machine length format makes it a common choice for tight-clearance work and fixture drilling where a standard-length bit would flex or chatter. The heavy-duty cobalt grade handles interrupted cuts and hard alloys that would quickly degrade lower-grade tooling. It carries a straight-cylindrical shank measuring 0.1990 inches in diameter, compatible with standard drill chucks across the common size range.

Key Features

• Cobalt construction rated for heavy-duty drilling in hard and abrasive metals
• 135-degree split point reduces thrust force and eliminates center-punch requirement
• TiN coating lowers friction, extends cutting edge life, and resists heat buildup
• Stub screw machine length (2.25 inches OAL) provides rigidity and reduces deflection
• Web-thinned parallel web improves chip evacuation and cutting efficiency
• Right-hand spiral flute with straight-cylindrical shank fits standard drill chucks

Compatibility

Designed as an OEM-style replacement or direct-use drill bit for applications requiring wire gauge size 8 (0.1990 inches) within the 0.1500 to 0.2000 inch drill bit size range, using standard straight-cylindrical shank drill chucks.

Installation Notes

Installation is performed by machinists or maintenance trades using standard drill chuck tooling. Secure the shank fully in the chuck and verify concentricity before drilling. Always wear appropriate eye protection and secure workpieces to prevent rotation. Coolant-through is not supported on this bit; use external cutting fluid on hard materials to manage heat and preserve the TiN coating.