Chicago-latrobe 48243 Screw Machine Drill Bit 0.29 in Hss

Product Description

The CHICAGO-LATROBE 48243 is a screw machine length drill bit designed for high-production drilling in ferrous metals, including cast iron and steel. Built from high speed steel (HSS) with a coated finish, this bit features a 135-degree split point that reduces walking and allows drilling without a center punch. The web-thinned, parallel web configuration lowers cutting resistance and improves chip evacuation. At 0.29 inches in diameter (Letter size L), the 48243 belongs to the Series 2159 heavy-duty line and is suited for machinists, tool and die shops, and trade professionals working with structural steel or cast components.

This bit is built for screw machine length applications where a shorter, stiffer tool is required to maintain accuracy in production drilling setups. Its straight-cylindrical shank seats reliably in drill chucks and screw machine collets. Primary workpiece materials are cast iron and steel, making it a practical choice for HVAC equipment fabrication, pipe fitting, structural framing, and similar metal drilling tasks performed by mechanical and industrial tradespeople. The regular spiral flute pattern handles a wide range of feed rates without clogging.

Key Features

• 135-degree split point reduces bit walking and eliminates center-punch requirements on most applications
• Web-thinned, parallel web construction lowers thrust force and improves chip clearance
• High speed steel construction with coated finish for extended service life in ferrous materials
• Screw machine length body provides added rigidity and improved hole accuracy versus jobber-length bits
• Right-hand cut with 2-flute regular spiral geometry compatible with standard drill press and hand drill setups
• Meets NAS 907 and ISO standards for dimensional and performance consistency

Compatibility

Designed as a heavy-duty OEM-style replacement or production drill bit for use in cast iron and steel workpieces. Fits any drill press, screw machine, or hand drill accepting a straight-cylindrical shank of 0.29 inches diameter.

Installation Notes

Installation and use should be performed by qualified machinists or trade professionals familiar with metal drilling operations. Secure the workpiece fully before drilling to prevent rotation and ensure clean, accurate holes. Use appropriate cutting fluid or coolant on the workpiece material to extend bit life, noting this bit does not support coolant-through delivery. Inspect the cutting edges before each use and replace the bit if chipping or excessive wear is observed.