Chicago-latrobe 50859 Cobalt Screw Machine Drill Bit

Product Description

The CHICAGO-LATROBE 50859 is a cobalt screw machine length drill bit designed for heavy-duty drilling in tough materials including cast iron and steel. Built to Series 559 standards, it features a 135-degree split point that reduces walking at startup and lowers the thrust needed to break through hard workpieces. The web-thinned, parallel-web construction improves chip evacuation and cutting efficiency. At 0.209 inches in diameter, this bit corresponds to Wire Size No. 4 and delivers tight dimensional accuracy with a tolerance of +0.0000 to -0.0007 inches. It is suited for production environments where consistent hole quality and tool longevity are required.

This drill bit is intended for use in screw machine operations and general metalworking applications involving cast iron and steel. Its shorter screw machine length body provides added rigidity compared to jobber-length bits, making it a practical choice for CNC drilling, turret lathes, and automated production setups where reduced deflection matters. A straight-cylindrical shank ensures compatibility with standard three-jaw chucks and collet holders. The M42 cobalt material grade gives this bit heat resistance that extends tool life when cutting at higher speeds without coolant-through capability.

Key Features

• M42 cobalt construction for heat resistance and extended tool life in ferrous materials
• 135-degree split point reduces thrust and prevents bit walk on entry
• Web-thinned, parallel-web design improves chip flow and cutting efficiency
• Screw machine length body provides greater rigidity than jobber-length alternatives
• Right-hand cut with regular spiral flute geometry for standard clockwise drilling
• Diameter tolerance of +0.0000 to -0.0007 inches for consistent, close-tolerance hole production

Compatibility

Designed as an OEM-style replacement or direct-use drill bit for metalworking applications in cast iron and steel; straight-cylindrical shank fits standard three-jaw chucks and collet-style toolholders used in screw machines, CNC lathes, and drill presses.

Installation Notes

Install in a properly sized chuck or collet holder and verify the shank is fully seated and secured before operation. Power down the machine and confirm it is in a locked-out state before changing bits. Use appropriate cutting fluid for the workpiece material when operating at higher spindle speeds to manage heat buildup, even though this bit does not feature coolant-through capability. Follow applicable shop safety and machine guarding practices throughout setup and use.