Import BDNA--20921-1 Mechanics Drill Bit 25/64 in Hss

Product Description

The IMPORT BDNA--20921-1 is a mechanics-length twist drill bit designed for general-purpose metal drilling in production and maintenance environments. Built from high-speed steel with an oxide finish, it measures 25/64 inches (0.3906 inches decimal) in diameter with a 135-degree split point that self-centers on contact and reduces walking without a center punch. Overall length is 4-5/16 inches with a 2-3/4 inch flute length. The Weldon flat shank with three flats locks securely in chuck collets to prevent rotation under load. Right-hand spiral flutes evacuate chips efficiently during through-hole and blind-hole operations.

This drill bit is suited for drilling carbon steel, cast iron, high alloy steel, high tensile strength alloys, stainless steel, and general steel stock. The mechanics-length body provides added rigidity over jobber-length bits, making it well-suited for close-tolerance work in tight spaces on machine beds, fixtures, and structural assemblies. It is appropriate for use in drill presses, milling machines, and hand-held power tools equipped with compatible Weldon flat chuck systems. General-purpose tool performance makes it a practical stock item for fabrication shops, maintenance facilities, and field service kits.

Key Features

• 25/64 inch diameter (0.3906 inches decimal) for precise hole sizing
• 135-degree split point self-centers and reduces thrust force on entry
• High-speed steel construction handles steel, cast iron, and stainless steel workpieces
• Weldon flat shank with three flats prevents rotation slip in driven chucks
• Web-thinned parallel web reduces cutting resistance and improves chip clearance
• Oxide finish provides mild corrosion resistance and reduces friction during cutting

Compatibility

Designed as a general-purpose mechanics-length drill bit compatible with Weldon flat chuck systems and drill presses or power tools that accept a 25/64 inch Weldon shank. Suitable for workpieces in carbon steel, cast iron, high alloy steel, high tensile strength alloy, stainless steel, and general steel.

Installation Notes

Installation and use should be performed by a qualified machinist or trained tradesperson familiar with rotary cutting tools. Secure the Weldon flat shank fully in the chuck and verify all set screws are tightened against the flats before operating. Wear appropriate eye protection and ensure the workpiece is clamped or fixtured before drilling. Do not exceed the recommended feed and speed range for the workpiece material, and allow the bit to cool or apply cutting fluid when drilling hard alloys or stainless steel to preserve tool life.