Chicago-latrobe 48236 Letter D Screw Machine Drill Bit Hss

Product Description

The CHICAGO-LATROBE 48236 is a screw machine length drill bit designed for high-production drilling in tight-clearance applications. It carries a Letter D size designation, which corresponds to 0.2460 inches in decimal. The 135-degree split point reduces walking and requires less feed pressure at entry, making it well suited for drilling into cast iron and steel without a center punch. The high-speed steel construction with a coated finish resists heat buildup during continuous use. Two spiral flutes evacuate chips efficiently, and the web-thinned, parallel-web configuration keeps cutting forces low. Licensed machinists, maintenance mechanics, and tool-and-die tradespeople install and use this bit in drill presses, CNC turret machines, and hand-held pneumatic drills.

The 48236 is built to the NAS 907 specification under the NAS designation and meets ISO standards, making it appropriate for aerospace, automotive, and general metalworking environments. Its screw machine length profile — shorter overall length than a jobber bit — provides added rigidity when drilling in limited-space fixtures or multi-spindle setups. The straight-cylindrical shank fits standard drill chucks without adapters. This bit is rated for heavy-duty performance and is a practical choice for shops that drill cast iron and steel plate on a regular basis.

Key Features

• Letter D size (0.2460 inches) with a tight diameter tolerance of +0.0000 to -0.0007 inches
• 135-degree split point for reduced thrust and no-walk entry on ferrous materials
• Screw machine length for increased rigidity in confined or fixture-mounted setups
• Web-thinned parallel web lowers cutting resistance and extends tool life
• High-speed steel with coated finish for heat and wear resistance
• Meets NAS 907 specification and ISO standards for use in regulated industries

Compatibility

Designed for drilling cast iron and steel. The straight-cylindrical shank (0.2460 inches diameter) fits standard drill chucks used in drill presses, turret lathes, CNC screw machines, and handheld pneumatic or electric drills.

Installation Notes

Installation and use should be performed by qualified machinists or maintenance technicians familiar with metal-cutting tool practices. Secure the shank fully in the chuck and confirm runout before drilling. Always power down and lock out the machine before changing bits. Use appropriate cutting fluid or coolant rated for the workpiece material to maximize bit life, noting that this bit does not support through-coolant delivery.