Chicago-latrobe 49397 Screw Machine Drill Bit 0.144 in Hss

Product Description

The CHICAGO-LATROBE 49397 is a screw machine length drill bit designed for high-production drilling in ferrous and cast iron workpieces. Built from high speed steel with a coated finish, it measures 0.144 inches (wire size 27) in diameter with an overall length of 2-1/16 inches and a 1-inch flute length. The 135-degree split point reduces walking and requires less feed pressure at entry, making it well suited for heavy-duty shop and field drilling applications. Right-hand spiral flutes evacuate chips efficiently during through-hole operations. This bit meets NAS 907 and ISO standards, confirming dimensional and performance consistency for professional use.

Screw machine length drill bits are shorter than jobber-length bits, which increases rigidity and reduces deflection in close-tolerance drilling setups. The 49397 is intended for use in drill presses, CNC turret lathes, screw machines, and hand-held power drills where a stiffer bit improves hole accuracy. Primary workpiece materials include cast iron and steel, making it a practical choice for HVAC bracket fabrication, plumbing rough-in metalwork, electrical panel work, and general mechanical assembly. It is sold individually but requires a minimum order of 12 units per order.

Key Features

• 0.144 inch diameter (wire size 27) with a diameter tolerance of +0.0000 to -0.0007 inches for consistent close-tolerance holes
• 135-degree split point reduces entry walking and lowers required feed force on steel and cast iron
• Web-thinned parallel web construction improves chip clearance and reduces heat buildup at the cutting edge
• Screw machine length (2-1/16 inches overall) provides added rigidity and reduced deflection compared to jobber-length bits
• High speed steel construction with coated finish extends service life in repetitive production drilling
• Meets NAS 907 and ISO standards for dimensional accuracy and heavy-duty performance

Compatibility

Designed for use in standard straight-shank drill chucks on drill presses, screw machines, CNC turret lathes, and hand-held power drills. Rated for primary workpiece materials of cast iron and steel per Series 159 heavy-duty specifications.

Installation Notes

A licensed machinist or qualified tradesperson should secure the shank fully in a properly sized chuck before operating. Ensure the workpiece is firmly clamped and the drill press or machine is powered down before changing or inspecting bits. Use appropriate cutting fluid when drilling steel to extend bit life and maintain hole quality. Inspect the cutting edge for wear regularly, as a dull split point will increase heat and reduce hole accuracy.