Hertel 66693474 Screw Machine Drill Bit Letter J Hss Tin

Product Description

The HERTEL 66693474 is a screw machine length drill bit sized to Letter J (0.2770 inches decimal), designed for high-production drilling in metal fabrication, machining, and maintenance applications. Built from high-speed steel (HSS) with a titanium nitride (TiN) coating, it delivers extended tool life and reduced friction in ferrous and non-ferrous materials. The 135-degree split point starts on contact without a center punch and reduces walking on smooth surfaces. At 2-11/16 inches overall length, the screw machine format provides added rigidity over jobber-length bits, making it well suited to drill press and CNC turret work where stub-length stiffness is needed.

This bit is used in production environments where hole consistency and reduced cycle time matter. The right-hand spiral flute with regular helix efficiently evacuates chips in through-hole and blind-hole drilling operations. Web-thinned geometry with a parallel web configuration reduces thrust load. It fits any drill press, turret, or hand drill with a straight chuck accepting a 0.2770-inch straight-cylindrical shank. Heavy-duty grade construction handles interrupted cuts and tougher workpiece materials without premature edge breakdown.

Key Features

• Letter J size - 0.2770 inches decimal diameter for precise hole sizing
• 135-degree split point starts on contact, reduces thrust and eliminates center-punch step
• TiN coating extends cutting edge life and lowers friction heat in metal drilling
• Screw machine (stub) length - 2-11/16 inches OAL for increased rigidity over jobber bits
• Web-thinned parallel web reduces axial load and improves chip flow
• Heavy-duty grade HSS construction rated for production and interrupted-cut use

Compatibility

Designed as an OEM-style replacement or production-grade substitute for Letter J screw machine length drill bits used in standard straight-shank drill chucks across drill presses, CNC turrets, and hand-held power drills.

Installation Notes

Installation is performed by machinists, tool-and-die trades, and maintenance technicians. Secure the straight-cylindrical shank fully in a keyed or keyless chuck before operation and verify runout before high-tolerance drilling. Disengage and de-energize the machine before changing bits. Do not exceed the recommended feed rate for the workpiece material - excessive feed pressure will chip the TiN coating and collapse the split point prematurely.