Sumitomo U101138 Screw Machine Drill Bit 23/64 Carbide

Product Description

The SUMITOMO U101138 is a solid carbide screw machine length drill bit designed for high-performance drilling in demanding metalworking applications. Built in the MDW-HGS series, it features a 23/64 inch (0.3594 inch) diameter, a 135-degree split point, and a coated finish that extends tool life in abrasive materials. With a tapered web configuration and two-flute geometry, the U101138 is engineered for efficient chip evacuation and precise hole entry. Coolant-through capability allows internal coolant delivery directly to the cutting edge, reducing heat buildup during deep or high-cycle drilling. This bit is installed and operated by machinists and toolroom professionals in production and job-shop environments.

The U101138 is suited for drilling cast iron, stainless steel, and steel in CNC machining centers, drill presses, and automated production equipment. Its screw machine length profile provides added rigidity compared to jobber-length bits, making it well-suited for short, accurate holes where runout control and repeatability matter. The straight-cylindrical shank fits standard drill chucks and collet holders without modification. A flute-by-diameter ratio of 3xD supports drilling depths up to 1.2335 inches in a single pass with internal coolant support.

Key Features

• Solid carbide construction for rigidity and wear resistance in ferrous metals
• 135-degree split point reduces walking and lowers thrust force at entry
• Coated finish extends tool life in cast iron, stainless steel, and steel
• Coolant-through design delivers coolant directly to the cutting zone
• Tapered web with 2-flute geometry promotes effective chip evacuation
• h8 diameter tolerance ensures consistent fit and hole accuracy

Compatibility

Designed as an OEM-style screw machine length drill bit for use in standard straight-cylindrical shank drill chucks and collet systems; compatible with primary workpiece materials including cast iron, stainless steel, and steel.

Installation Notes

Installation and operation should be performed by qualified machinists familiar with carbide tooling. Ensure the machine spindle and chuck or collet are clean and free of debris before seating the shank to prevent runout. Carbide tooling is brittle — avoid side loading, interrupted cuts at high feed rates, or dropping the bit, as chipping or fracture can occur. Verify that coolant-through passages are clear and coolant pressure is set appropriately for the machine before beginning a drilling cycle.