Sumitomo U101091 Screw Machine Drill Bit 0.277in Carbide

Product Description

The SUMITOMO U101091 is a solid carbide screw machine length drill bit designed for precision drilling in demanding production environments. Measuring 0.277 inches (Letter size J) in diameter with a 135-degree split-point geometry, it delivers fast, accurate hole entry with minimal walking. The overall length is 2.874 inches, making it compact and rigid for high-speed drilling applications. With a 2-flute straight-cylindrical shank and tapered web configuration, this bit is built to handle cast iron and steel workpieces. It is part of the MDW-GS series and carries an h8 diameter tolerance for tight dimensional control in close-tolerance work.

The U101091 is suited for production machining, job shop drilling, and CNC applications requiring short, rigid tooling. Screw machine length bits like this one are commonly used in turret lathes, screw machines, and machining centers where minimal overhang and high rigidity reduce deflection. Primary workpiece materials include cast iron and steel, making it a practical choice for general metalworking and precision component manufacturing. The flute-to-diameter ratio is 2xD, supporting chip evacuation in shallow to moderate-depth holes without coolant-through features.

Key Features

• Solid carbide construction for hardness and wear resistance in ferrous materials
• 135-degree drill point angle reduces entry thrust and minimizes workpiece deformation
• Tapered web design improves self-centering and reduces chisel edge contact
• Straight-cylindrical shank for standard collet and chuck compatibility
• h8 diameter tolerance ensures consistent fit in precision toolholders
• 2-flute geometry promotes efficient chip evacuation in cast iron and steel

Compatibility

Designed as an OEM-style screw machine length drill bit for use in standard straight-shank collets, drill chucks, and toolholders compatible with 0.277-inch diameter shanks across CNC machining centers, turret lathes, and screw machines.

Installation Notes

This drill bit is installed by machinists and CNC tooling technicians using standard collet chucks or drill chucks rated for the shank diameter. Ensure the machine spindle is fully stopped and locked before changing tooling. Confirm runout and tool projection meet the requirements of the workpiece drawing before beginning a production run. Coolant-through is not supported on this bit; verify that external coolant or cutting fluid delivery is adequate for the workpiece material and cutting parameters.