Hertel 42284 Cobalt Jobber Drill 8.00 Mm 135 Deg

Product Description

The HERTEL 42284 is an M35 cobalt jobber-length drill bit designed for drilling into stainless steel, hardened materials, and other tough alloys that wear out standard high-speed steel tooling. It measures 8.00 mm (0.3150 inches) in diameter with an overall length of 117.00 mm (4.6063 inches) and a flute length of 75.00 mm (2.9528 inches). The 135-degree split-point geometry self-centers on contact, reducing the need for a center punch and minimizing walking on hard surfaces. The oxide finish provides baseline lubricity and heat resistance during cutting. This bit is sold individually and is suited for use in machining, fabrication, and maintenance environments.

This drill bit is intended for right-hand rotation in standard drill presses, CNC machines, and handheld power drills. Its primary application is drilling stainless steel and hardened materials where heat buildup and edge wear are the main concerns. The 5xD flute-to-diameter ratio and regular spiral flute design provide efficient chip evacuation in deep-hole applications. It is well suited for metal fabrication shops, MRO facilities, and field maintenance work where consistent performance in difficult materials is required.

Key Features

• M35 cobalt construction for superior heat resistance in stainless steel and hardened materials
• 135-degree split-point tip self-centers and reduces thrust force at entry
• Regular spiral flute design promotes efficient chip evacuation during drilling
• Straight cylindrical shank fits standard drill chucks without modification
• Oxide finish adds lubricity and baseline corrosion resistance
• Right-hand cutting direction compatible with all standard drill equipment

Compatibility

Designed as an OEM-style jobber drill bit compatible with standard drill chucks and collet systems accepting 8.00 mm straight-shank tooling. Primary workpiece materials listed by the manufacturer are stainless steel and hardened materials.

Installation Notes

Secure the shank fully in the chuck before operation and verify chuck tightness to prevent slippage under torque. When drilling stainless steel or hardened alloys, use appropriate cutting fluid or lubricant to extend tool life and manage heat buildup. Reduce feed pressure as the drill breaks through the exit side of the workpiece to prevent bit damage and burring. This bit does not support coolant-through delivery and should not be used in applications requiring internal coolant feed.