Hertel 66693839 Jobber Drill Bit Letter J Tin Hss

Product Description

The HERTEL 66693839 is a letter-J jobber-length drill bit designed for production holemaking in metal, wood, and composite materials. It is manufactured from high speed steel with a titanium nitride (TiN) coating that extends cutting life and reduces heat buildup at the cutting edge. The split point at 135 degrees starts on contact without a center punch and reduces walking on flat or curved surfaces. With an overall length of 4.125 inches and a flute length of 2.875 inches, it fits standard drill chucks and drill press spindles. This is a heavy-duty grade bit suited for shop, field, and maintenance use.

The 66693839 is used wherever a 0.2770-inch (letter J) hole is required. Typical applications include metalworking, fabrication, HVAC equipment assembly, plumbing rough-in, electrical panel work, and general maintenance tasks. The jobber-series length is the standard choice for through-hole and blind-hole work in materials of moderate thickness. A straight-cylindrical shank with a diameter of 0.2770 inches seats directly in keyless or keyed chucks across most portable drills, drill presses, and mill collets.

Key Features

• 135-degree split point starts on contact and reduces drill walking without center punching
• TiN coating increases surface hardness and extends tool life compared to uncoated HSS
• High speed steel construction handles steel, aluminum, cast iron, and most plastics
• Web-thinned, tapered web design reduces thrust and improves chip evacuation
• Regular spiral, 2-flute configuration clears chips efficiently in through-hole and blind-hole applications
• Heavy-duty grade construction rated to NAS specification

Compatibility

Designed as a standard jobber-length drill bit with a straight-cylindrical shank; fits any keyed or keyless drill chuck or collet sized for a 0.2770-inch shank diameter.

Installation Notes

Install and remove the bit only when the drill or drill press is powered off and at a full stop. Secure the shank fully into the chuck with no less than the minimum recommended grip depth for the chuck model in use. Use cutting fluid or coolant when drilling ferrous metals to preserve coating life, except where the tool is used in a dry-cutting setup rated for TiN-coated tooling. Worn or chipped bits should be replaced rather than reground without proper relief-angle tooling.