Chicago-latrobe 49099 Screw Machine Drill Bit 0.136in Hss

Product Description

The CHICAGO-LATROBE 49099 is a screw machine length drill bit designed for general-purpose drilling in production and repair environments. Built from high speed steel with a bright, uncoated finish, this bit features a left-hand spiral flute and a standard 118-degree point angle. The shortened screw machine length provides added rigidity compared to jobber-length bits, reducing deflection in close-tolerance drilling. The straight-cylindrical shank seats cleanly in standard three-jaw chucks and quick-change holders. Wire size designation is #29, equivalent to 0.1360 inches in diameter. This bit is suitable for machinists, fabricators, and maintenance technicians working in metal shops, production lines, and service environments.

The 49099 is well suited for drilling aluminum, copper, magnesium, thermoplastics, wood, and slate. The left-hand cutting direction makes it particularly useful for removing broken right-hand fasteners and studs, a common task in mechanical and maintenance work. The screw machine length body keeps the bit stiff during pecking operations in short-stroke drill presses and CNC turret setups. The two-flute spiral configuration clears chips efficiently from the cut zone.

Key Features

• Left-hand cut removes broken right-hand fasteners and studs without an extractor in many applications
• 118-degree standard point angle works across a broad range of workpiece materials
• Screw machine length body provides greater rigidity and reduced deflection versus jobber length
• High speed steel construction handles general-purpose metal, plastic, and wood drilling
• Web-thinned parallel web reduces thrust and improves penetration at entry
• Diameter tolerance held to +0.0000 to -0.0007 inches per ISO standards

Compatibility

Designed as a general-purpose replacement or production drill bit in the CHICAGO-LATROBE Series 157L range, compatible with any standard three-jaw drill chuck or quick-change holder accepting a straight-cylindrical shank at 0.136 inches diameter.

Installation Notes

Install in a properly rated drill press, lathe tailstock, or hand drill with a chuck capacity covering 0.136 inches. Secure the shank fully in the chuck before operation and verify runout is within acceptable tolerance for the application. Wear appropriate eye protection and secure the workpiece firmly before drilling. Left-hand bits are typically run in reverse on a drill press or lathe to back out broken fasteners; confirm spindle direction before starting.