Hertel 66691445 Cobalt Screw Machine Drill Bit 27/64 in

Product Description

The HERTEL 66691445 is a cobalt screw machine length drill bit designed for high-performance drilling in tough materials. Built from heavy-duty cobalt steel and finished with a titanium nitride (TiN) coating, this bit handles hard steels, stainless, and abrasive alloys where standard HSS bits fail prematurely. It measures 27/64 inch (0.4200 inch decimal) in diameter with a 3-3/8 inch overall length, making it compact enough for close-quarters drilling applications. The 135-degree split point starts on contact without a center punch, reducing walking and improving hole accuracy. Licensed machinists, tool-and-die workers, and maintenance mechanics rely on this type of bit for production and repair drilling.

Screw machine length drill bits are shorter than jobber-length bits, providing added rigidity and reduced deflection in drill press, CNC, and turret lathe applications. The 66691445 is suited for metal fabrication shops, production machining environments, and industrial maintenance applications where hole consistency and bit longevity are critical. The right-hand spiral flute configuration and parallel web promote efficient chip evacuation during through-hole and blind-hole drilling in ferrous and non-ferrous metals.

Key Features

• Cobalt construction rated as heavy-duty grade for drilling hard and abrasive metals
• TiN coating extends cutting edge life and reduces friction during drilling
• 135-degree split point starts on contact, eliminating center punch requirement
• Web-thinned parallel web reduces thrust force and improves chip flow
• Straight-cylindrical shank fits standard drill chucks and collets without modification
• 2-inch flute length provides adequate chip clearance for the bit diameter

Compatibility

Designed as a direct-fit replacement screw machine length drill bit for use in drill presses, CNC machining centers, and turret lathes accepting a 0.4219-inch straight-cylindrical shank.

Installation Notes

Install and remove drill bits only with the machine powered down and the spindle at a full stop. Secure the shank fully in the chuck or collet to the recommended depth before tightening. Use appropriate cutting fluid or coolant for the material being drilled; note this bit does not support coolant-through delivery. Inspect the cutting edges for wear or chipping before each use and replace when edge degradation is visible to maintain hole quality and prevent workpiece damage.