Hertel 66693854 Jobber Drill Bit Letter L 0.290 in Hss Tin

Product Description

The HERTEL 66693854 is a letter-size jobber-length drill bit in size L (0.290 inches), designed for general-purpose holemaking in metal, wood, and composite materials. The bit is manufactured from high speed steel (HSS) with a titanium nitride (TiN) coating that increases surface hardness and extends tool life in production drilling applications. The 135-degree split point reduces walking on entry and requires less thrust than a standard 118-degree point. At 4.25 inches overall length with a 2.9375-inch flute length, this is a standard jobber-series geometry suited to a wide range of drill press, lathe, and hand-drill applications. A tapered, web-thinned configuration keeps cutting forces low at the chisel edge.

This drill bit is appropriate for machinists, maintenance technicians, fabricators, and tool-and-die professionals working in light to heavy-duty production or repair environments. The straight-cylindrical shank at 0.290 inches diameter fits standard three-jaw chucks without a reducer. Right-hand spiral flute geometry evacuates chips efficiently in through-hole drilling. The heavy-duty grade designation and NAS specification alignment make this bit a sound choice for critical-tolerance holemaking where dimensional accuracy and repeat performance matter.

Key Features

• Letter L size - 0.290 inches decimal equivalent for precise hole sizing
• 135-degree split point with web thinning reduces thrust and self-centers on entry
• TiN coating over HSS substrate extends tool life and reduces heat buildup
• Regular spiral, two-flute design for efficient chip evacuation
• Straight-cylindrical shank fits standard drill chucks without adapters
• NAS specification designation for dimensional and performance conformance

Compatibility

Designed as an OEM-compatible jobber-series drill bit suitable for standard three-jaw drill chucks accepting a 0.290-inch straight-cylindrical shank in drill presses, CNC drilling centers, lathes, and hand-held power drills.

Installation Notes

Installation and use should be performed by qualified machinists or trained tradespeople familiar with rotating cutting tools. Always secure the workpiece with a vise or clamp before drilling - never hand-hold small parts. Confirm chuck runout is within acceptable limits before use, as excessive runout accelerates wear on a coated HSS bit. Cutting fluid or mist coolant is recommended when drilling ferrous materials at higher feed rates, even though this bit does not have through-coolant capability.