Accupro 10399 Solid Carbide Jobber Drill Bit 5/16 in

Product Description

The ACCUPRO 10399 is a solid carbide jobber-length drill bit sized at 5/16 inches (0.3125 inches) in diameter, designed for precision drilling in hard and abrasive materials. Built from solid carbide, this bit delivers higher rigidity and heat resistance compared to high-speed steel alternatives. The 150-degree split-point tip reduces walking and allows for faster penetration with less axial thrust. At 3-3/4 inches overall length with a 1-7/8-inch flute length, it fits standard drill chucks and is well-suited for production machining, maintenance shops, and toolroom work. Machinists, maintenance technicians, and metalworking professionals are the primary users.

This drill bit is intended for use in CNC machining centers, drill presses, and handheld power tools where a straight-cylindrical shank is appropriate. Its 3-flute spiral configuration improves chip evacuation and supports a 5xD flute-to-diameter ratio, making it effective for drilling into steel, cast iron, hardened alloys, and similar ferrous and non-ferrous materials. The right-hand cutting direction is standard for conventional drilling operations. It is sold individually and conforms to ANSI specification designations.

Key Features

• Solid carbide construction provides superior rigidity and wear resistance over HSS bits
• 150-degree drill point angle reduces tip walking and lowers entry thrust
• 3-flute spiral design improves chip clearance and supports faster feed rates
• Bright uncoated finish suitable for general-purpose metalworking applications
• Straight-cylindrical shank fits standard drill chucks without adapters
• ANSI-compliant jobber length for consistent interchangeability

Compatibility

Designed as a standard jobber-length drill bit with a straight-cylindrical shank, this bit is compatible with any drill press, CNC machining center, or handheld drill accepting a 5/16-inch straight shank.

Installation Notes

Secure the shank fully in the drill chuck and verify runout before starting the cut. Solid carbide bits are brittle compared to HSS — avoid side loading, interrupted cuts without proper support, and excessive feed rates that can cause chipping or breakage. For CNC applications, confirm spindle speed and feed rate are appropriate for the workpiece material before initiating the drill cycle. No coolant-through capability is present on this bit; apply external cutting fluid as needed per shop practice.