Hertel 42129 Cobalt Jobber Drill Bit 1/8 Inch 135 Degree

Product Description

The HERTEL 42129 is a cobalt jobber-length drill bit engineered for drilling stainless steel, hardened materials, and other tough alloys that defeat standard high-speed steel tooling. Built to M35 cobalt material grade, the bit carries a 135-degree split-point geometry that reduces walking on entry and lowers the thrust required to penetrate hard workpieces. The straight cylindrical shank fits standard drill chucks without a reducer. At 2.75 inches overall length with a 1.625-inch flute, this is a standard jobber-series proportioned tool suited to bench drill presses, hand drills, and drill motors used daily in fabrication, mechanical, and maintenance work.

This bit is sized at 0.125 inches (1/8 inch) diameter and is intended for production and maintenance applications where heat buildup and work hardening are common concerns. The regular spiral flute at a 5xD ratio clears chips efficiently without packing. Right-hand cutting direction matches conventional drill press and hand drill operation. No coolant-through feature is present, so flood or mist coolant must be applied externally when drilling deep holes in stainless or hardened material. It ships individually and is sold at a minimum order quantity of 12 units.

Key Features

• M35 cobalt material grade handles stainless steel and hardened workpieces
• 135-degree split-point tip reduces bit walking and lowers feed pressure
• Regular spiral flute with 5xD ratio promotes efficient chip evacuation
• Oxide finish provides mild heat resistance and surface protection
• Straight cylindrical shank fits standard drill chucks without adapters
• Right-hand cutting direction, 2-flute configuration for clean hole finish

Compatibility

Designed as a standard jobber-length drill bit for use in any drill press, hand drill, or drill motor accepting a straight cylindrical shank. Primary workpiece materials listed by the manufacturer are stainless steel and hardened materials.

Installation Notes

Install and service by a qualified machinist or maintenance technician. Secure the workpiece firmly before drilling to prevent rotation or movement. Apply external cutting fluid or mist coolant when drilling stainless steel or hardened alloys to manage heat and extend tool life. Inspect the cutting edges before each use and replace any bit showing chipping, dullness, or deformation to maintain hole quality and operator safety.