Hertel 66693938 Jobber Drill Bit Letter T Hss Tin

Product Description

The HERTEL 66693938 is a letter-size T jobber-length drill bit designed for production holemaking in metal and similar materials. Built from high speed steel (HSS) with a titanium nitride (TiN) coating, the bit delivers extended tool life and reduced friction compared to uncoated HSS. The 135-degree split point starts on contact without a center punch and reduces walking on flat or curved workpieces. With an overall length of 4-7/8 inches and a flute length of 3-1/2 inches, it handles standard jobber-depth holes efficiently. This bit is installed and used by machinists, maintenance technicians, pipefitters, and general trade professionals working with drill presses or handheld power drills.

The 66693938 is suited for general-purpose drilling in ferrous metals, non-ferrous metals, and hard plastics. The straight-cylindrical shank at 0.358 inches diameter fits standard 3-jaw drill chucks across benchtop drill presses, magnetic drill presses, and hand drills. The right-hand spiral flute geometry evacuates chips efficiently during through-hole and blind-hole drilling. It is designated to NAS specification standards, making it appropriate for maintenance, repair, and light manufacturing environments where dimensional accuracy and consistent performance are required.

Key Features

• 135-degree split point starts on contact and self-centers without a center punch
• TiN coating extends tool life and reduces heat buildup during cutting
• High speed steel construction rated for heavy-duty drill bit grade applications
• Web-thinned, tapered web configuration reduces thrust and improves chip flow
• Right-hand, regular spiral flute for efficient chip evacuation
• NAS specification designation for consistent manufacturing standards

Compatibility

Designed as a jobber-length drill bit with a 0.358-inch straight-cylindrical shank, compatible with any standard 3-jaw drill chuck that accepts shank diameters in the 0.3500 to 0.4000 inch range.

Installation Notes

Install and remove drill bits only with the drill or drill press fully powered off and the chuck key removed from the chuck. Secure the workpiece with a clamp or vise before drilling - never hand-hold metal workpieces against a drill press. Use appropriate cutting fluid for ferrous metals to extend bit life and maintain bore quality. Inspect the cutting edges for wear before each use; a dull bit increases thrust, generates excess heat, and reduces hole accuracy.