Chicago-latrobe 48731 Screw Machine Drill Bit 0.12 in Hss

Product Description

The CHICAGO-LATROBE 48731 is a screw machine length drill bit designed for high-cycle drilling in metal fabrication and trade maintenance applications. Built from high speed steel (HSS) with a bright, uncoated finish, this bit runs a 0.12 inch (No. 31 wire gauge) diameter with a standard 118-degree point angle and a two-flute spiral configuration. The shorter screw machine length body provides added rigidity compared to jobber-length bits, reducing deflection and improving hole accuracy when drilling from a fixed machine or drill press. It carries a diameter tolerance of +0.0000 to -0.0005 inches, making it suitable for close-tolerance work in production environments.

This bit is suited for general-purpose drilling in cast iron, non-ferrous metals, and steel. The screw machine length format is commonly specified for CNC turret lathes, automatic screw machines, and drill press operations where stub rigidity and consistent depth control matter. Overall length is 1-7/8 inches with a 7/8 inch flute length and a straight-cylindrical shank that seats directly into standard chucks and collets without adapters. HVAC, plumbing, and electrical tradespeople also reach for this format when drilling in tight quarters or sheet metal boxes where a standard-length bit would flex or chatter.

Key Features

• No. 31 wire gauge diameter (0.1200 inches) with tight +0.0000 to -0.0005 inch tolerance
• High speed steel construction for durability across cast iron, non-ferrous metal, and steel workpieces
• 118-degree standard point angle with web-thinned, parallel web geometry for reduced thrust on entry
• Screw machine (stub) length body delivers superior rigidity and reduced bit deflection
• Right-hand cut, two-flute spiral design clears chips efficiently in through-hole and blind-hole drilling
• Bright, uncoated finish suitable for general-purpose use without added coating cost

Compatibility

Designed as a general-purpose screw machine length drill bit compatible with any standard chuck or collet accepting a straight-cylindrical shank. Suitable for use in CNC lathes, drill presses, and handheld drills wherever a No. 31 diameter stub-length bit is specified. Manufactured to ISO standards per Series 157.

Installation Notes

Secure the straight-cylindrical shank firmly in the chuck before operation and verify runout before beginning a drilling sequence. Disconnect or lock out power to any machine tool before changing bits, in accordance with OSHA lockout/tagout procedures. Use appropriate cutting fluid or lubrication when drilling ferrous metals to extend bit life and maintain dimensional accuracy. Discard any bit showing visible flute damage, tip chipping, or heat discoloration beyond normal wear.