Sumitomo U103729 25/64 Inch Solid Carbide Jobber Drill

Product Description

The SUMITOMO U103729 is a solid carbide jobber-length drill bit designed for high-performance metal cutting in demanding production environments. It measures 25/64 inch (0.3906 inch) in diameter with a 135-degree split-point geometry and a TiAlCr/TiSi multi-layer proprietary coating that extends tool life under high heat and abrasion. Overall length is 5.3543 inches with a flute length of 3.1496 inches and a straight cylindrical shank diameter of 0.3906 inch. The tapered web configuration improves chip evacuation and reduces thrust force. Licensed machinists and CNC operators working in job shops, aerospace, and heavy manufacturing environments are the primary users of this series.

The U103729 belongs to SUMITOMO's MDW-HGS series, which is engineered for through-coolant drilling at a 5xD flute-to-diameter ratio. Primary workpiece materials include cast iron, stainless steel, and carbon and alloy steels, corresponding to material codes K, M, P, and S. The coolant-through design makes it well suited for deep-hole drilling cycles where chip clearing and heat management are critical. It is used in CNC machining centers and drill presses running ferrous workpieces where tight tolerances and consistent hole quality are required across high-volume production runs.

Key Features

• Solid carbide construction for rigidity and wear resistance in ferrous cutting applications
• TiAlCr/TiSi multi-layer coating provides thermal barrier and oxidation resistance at elevated cutting speeds
• 135-degree point angle reduces entry thrust and centers the drill without a pilot hole
• Coolant-through channels deliver cutting fluid directly to the cutting edge for deep-hole cycles
• Tapered web geometry promotes positive chip flow and reduces re-cutting
• h8 diameter tolerance on the shank ensures consistent tool holder fitment
• 5xD flute ratio supports drilling depths up to five times the bit diameter

Compatibility

Designed for use in CNC machining centers and drill presses equipped with standard straight-shank toolholders accepting a 0.3906-inch shank. Compatible with cast iron, stainless steel, and steel workpieces as noted by material codes K, M, P, and S. Belongs to SUMITOMO MDW-HGS series.

Installation Notes

Installation and operation of solid carbide drill bits should be performed by qualified machinists or CNC technicians familiar with cutting tool setup and machine operation. Ensure the machine spindle and toolholder are clean and free of debris before seating the shank to maintain concentricity within the h8 tolerance specification. Verify coolant-through supply is active before beginning deep-hole cycles to prevent thermal cracking of the carbide substrate. Solid carbide is brittle — avoid side loads, interrupted cuts without appropriate feeds and speeds, and re-using a chipped cutting edge.