Sumitomo U101154 Screw Machine Drill Bit 25/64 Solid Carbide

Product Description

The SUMITOMO U101154 is a screw machine length drill bit engineered for high-performance drilling in demanding metalworking applications. Built from solid carbide with a coated finish, this bit measures 25/64 inch (0.3906 inches) in diameter and carries a 135-degree split-point geometry that promotes accurate self-starting and reduces thrust force. The MDW-HGS series design features a tapered web configuration and two margins for improved hole quality and straightness. At 4.1732 inches overall length with a 1.9685-inch flute length, it fits standard screw machine length tooling setups. Coolant-through construction channels cutting fluid directly to the tip, extending tool life in interrupted and deep cuts. Licensed machinists and CNC operators are the primary installers.

This drill bit is intended for drilling cast iron, stainless steel, and carbon steel in production machining environments. The screw machine length (stub) profile provides added rigidity compared to jobber-length bits, making it well suited for CNC machining centers, turret lathes, and drill presses where chatter control and hole accuracy are critical. The h8 diameter tolerance ensures consistent fit in precision toolholders. Maximum drilling depth reaches 1.3825 inches (35.12 mm), and the 3xD flute-to-diameter ratio supports efficient chip evacuation at recommended feed and speed parameters for each workpiece material.

Key Features

• Solid carbide construction delivers superior hardness and wear resistance for ferrous and hard-alloy workpieces
• 135-degree split-point angle reduces walking and lowers required thrust force at entry
• Coolant-through design delivers cutting fluid directly to the cutting edge for improved tool life and chip flushing
• Tapered web configuration with two margins promotes hole straightness and surface finish quality
• h8 diameter tolerance ensures consistent, repeatable fit in precision collets and toolholders
• Screw machine length profile provides increased rigidity versus jobber-length bits in short-reach setups

Compatibility

Designed for use in standard straight-shank toolholders and collet chucks accepting a 25/64 inch (0.3906 inch) cylindrical shank, within the MDW-HGS series range of 0.3500 to 0.4000 inch drill bit diameters.

Installation Notes

Installation should be performed by a qualified machinist or CNC setup technician. Ensure the machine spindle is fully stopped and locked out before inserting or removing the bit from the toolholder. Seat the straight-cylindrical shank fully and evenly in the collet or chuck to the specified grip length to prevent runout. Follow the tool manufacturer and machine builder recommendations for spindle speed, feed rate, and coolant pressure when cutting cast iron, stainless steel, or carbon steel.