Hertel 66691460 Screw Machine Drill Bit 29/64 in Cobalt

Product Description

The HERTEL 66691460 is a screw machine length drill bit designed for high-speed drilling in tough materials. Built from cobalt steel with a titanium nitride (TiN) coating, this bit handles hard steels, stainless, and other abrasion-resistant metals better than standard HSS tooling. It measures 29/64 inch (0.4531 inch decimal) in diameter with an overall length of 3-9/16 inches and a flute length of 2-1/8 inches. The 135-degree split point reduces walking and lowers thrust force at entry, making it well-suited for production and maintenance drilling where precision and tool life matter. Machinists, tool-and-die techs, and industrial maintenance mechanics are the primary users.

This bit fits screw machine and drill press applications in job shop, manufacturing, and MRO environments. The stub-length body improves rigidity compared to jobber-length bits, reducing deflection when drilling into hard or interrupted surfaces. It is appropriate for use in CNC drill presses, turret lathes, and gang-drilling setups where consistent hole quality across multiple cycles is required. The right-hand spiral flute design handles conventional drilling operations in ferrous and non-ferrous metals.

Key Features

• Cobalt steel construction with TiN coating for extended tool life in hard and abrasive materials
• 135-degree split point reduces thrust and prevents bit walking on entry
• Screw machine (stub) length body increases rigidity and reduces deflection
• Web-thinned parallel web configuration improves chip evacuation
• Straight-cylindrical shank fits standard drill chucks and collets sized to 0.4531 inch
• Heavy-duty grade rated for demanding production and maintenance drilling cycles

Compatibility

Designed as a direct-fit replacement or upgrade for standard screw machine length drill bits in the 0.4500 to 0.5000 inch decimal size range, compatible with any chuck or collet accepting a 0.4531 inch straight-cylindrical shank.

Installation Notes

Installation and use should be performed by qualified machinists or industrial maintenance personnel familiar with drill press and lathe operation. Secure the shank fully in the chuck or collet before operation and verify runout before drilling. Always wear appropriate eye protection and follow applicable machine guarding requirements. Coolant-through is not supported on this bit; apply external cutting fluid when drilling hard steels to prevent premature coating wear.