Accupro 50389 Carbide Jobber Drill Bit Letter I Altin

Product Description

The ACCUPRO 50389 is a solid carbide jobber-length drill bit sized to Letter I (0.272 inches) with an AlTiN (aluminum titanium nitride) coating and a 150-degree drill point angle. The three-flute, right-hand spiral design promotes faster chip evacuation and improved feed rates compared to standard two-flute geometry. At 3.5 inches overall length with a 1.5-inch flute length, this bit is proportioned for general-purpose drilling in a wide range of materials. It is installed and used by machinists, tool-and-die technicians, maintenance mechanics, and metalworking professionals who require tight tolerances and consistent hole quality.

This bit is well suited for drilling hardened steels, stainless alloys, cast iron, and high-temp alloys where coating durability and cutting-edge retention are priorities. The AlTiN coating provides thermal resistance at elevated cutting speeds, making it appropriate for production environments and CNC drilling operations where coolant-through tooling is not required. The straight cylindrical shank seats in standard drill chucks and collet holders without modification. Single-piece packaging supports individual tool management and replacement workflows in shop and field settings.

Key Features

• Solid carbide construction for rigidity and long tool life in hard materials
• AlTiN coating provides high-temperature oxidation resistance during dry or mist-cooled drilling
• 150-degree drill point angle reduces thrust force and improves self-centering on entry
• 3-flute geometry increases chip clearance and supports higher feed rates
• Regular spiral with 5xD flute-to-diameter ratio balances stiffness and chip flow
• Straight cylindrical shank fits standard chucks and collet systems
• ANSI specification compliance ensures dimensional consistency

Compatibility

Designed as a jobber-length drill bit for use in standard drill chucks, ER collet holders, and CNC machining centers that accept straight cylindrical shank tooling sized for the 0.25 to 0.30 inch diameter range.

Installation Notes

Installation and use should be performed by qualified machinists or tooling technicians familiar with cutting tool setup. Ensure the machine spindle is fully stopped and locked out before inserting or removing the bit from the chuck or collet. Confirm shank seating depth and runout with an indicator before beginning a production run. Coolant-through is not supported on this tool; use external coolant or air blast as appropriate for the workpiece material.