Hertel 42291 Cobalt Jobber Drill Bit 9mm 135 Deg

Product Description

The HERTEL 42291 is a cobalt jobber length drill bit designed for high-performance drilling in tough materials including stainless steel, hardened steels, and high-alloy metals. Built from M35 cobalt high-speed steel, the bit maintains cutting-edge integrity at elevated temperatures where standard HSS bits would fail. The 135-degree split point reduces walking on contact and allows drilling to begin without a center punch in most applications. With a 9 mm diameter and 125 mm overall length, this bit fits the jobber length standard used across most portable and bench-mounted drilling setups. It is suitable for machinists, maintenance technicians, and fabricators who drill abrasive or work-hardened materials regularly.

The HERTEL 42291 is intended for use in jobshops, maintenance facilities, fabrication shops, and production environments where cobalt tooling is specified for durability and heat resistance. The right-hand spiral flute with regular helix promotes efficient chip evacuation during through-hole and blind-hole drilling in ferrous and non-ferrous materials. This bit is used in handheld drills, drill presses, and CNC machines with straight-cylindrical shank toolholders. The bright uncoated finish is standard for cobalt drills and is compatible with cutting fluids and dry drilling applications.

Key Features

• M35 cobalt high-speed steel construction for heat and wear resistance in hard materials
• 135-degree split point reduces thrust and eliminates walking without a center punch
• Right-hand cutting spiral flute with regular helix for controlled chip evacuation
• Straight-cylindrical shank fits standard drill chucks without adapters
• Bright uncoated finish compatible with cutting fluid and dry drilling
• No coolant-through design suited for conventional handheld and bench drill applications

Compatibility

Designed as a jobber length replacement drill bit for applications requiring a 9 mm diameter in the 0.3500 to 0.4000 decimal inch size range, compatible with standard straight-cylindrical shank drill chucks on portable drills, drill presses, and CNC equipment.

Installation Notes

Installation and use of this bit should be performed by qualified machinists or trained technicians familiar with cutting tool safety. Secure the shank fully in the chuck and verify runout before drilling. Apply appropriate cutting fluid when drilling ferrous metals to extend tool life and reduce heat buildup. Do not exceed the recommended RPM for the workpiece material and drill diameter as determined by standard speeds-and-feeds references for cobalt tooling.