Chicago-latrobe 48391 Screw Machine Drill Bit 0.159 in Hss

Product Description

The CHICAGO-LATROBE 48391 is a screw machine length drill bit designed for high-production drilling in cast iron and steel. Built from high speed steel with a coated finish, this bit features a 135-degree split point that reduces walking and cuts through tough workpiece materials with less feed pressure. The shortened screw machine length body provides added rigidity compared to jobber-length bits, making it well suited for drill press, CNC, and turret lathe applications where chatter and deflection must be minimized. At 0.159 inches in diameter (Wire Size 21), it covers a range of tapping and clearance hole requirements common in metalworking and fabrication shops.

The 48391 is used in metal fabrication, machine shops, and maintenance environments where accurate, repeatable holes in cast iron and steel are required. The parallel web configuration and web-thinned point reduce thrust requirements and help maintain hole quality at production run rates. The straight-cylindrical shank fits standard drill chucks and quick-change holders without modification. This bit is appropriate for use in both manual drill presses and CNC drilling centers.

Key Features

• 135-degree split point reduces drill walk and lowers required feed force on hard materials
• Web-thinned, parallel web construction decreases cutting resistance during entry
• High speed steel construction with coated finish for extended tool life in ferrous materials
• Screw machine length body increases rigidity and reduces deflection versus jobber-length bits
• Right-hand cut with regular spiral flute for efficient chip evacuation
• Meets NAS 907 specification and is ISO-compliant for dimensional consistency

Compatibility

Designed as an OEM-style replacement or direct-use screw machine drill bit for metalworking applications involving cast iron and steel workpieces, fitting any standard drill chuck or quick-change holder that accepts a straight-cylindrical shank.

Installation Notes

Installation and use of this drill bit should be performed by qualified machinists or trade professionals familiar with drill press, lathe, or CNC equipment operation. Ensure the spindle is fully stopped and the machine is de-energized before changing bits or adjusting chuck pressure. Verify shank seating and chuck tightness before initiating a cut. Follow applicable shop safety standards and machine manufacturer guidelines for speed and feed selection based on workpiece material.