Import BDNA--20917-1 21/64 in Mechanics Drill Bit Hss

Product Description

The IMPORT BDNA--20917-1 is a mechanics-length twist drill bit designed for general-purpose hole-making in metal and ferrous materials. It features a 21/64-inch (0.3281 inch decimal) diameter with a 135-degree split point that self-centers on contact, reducing the need for a center punch and minimizing walking on hard surfaces. The bit is machined from high-speed steel (HSS) with an oxide finish for added surface protection. The three-flat Weldon shank locks securely in compatible chucks to resist slipping under torque. Overall length is 4-1/16 inches with a flute length of 2-9/16 inches.

This drill bit is suited for production and maintenance work involving carbon steel, cast iron, high alloy steel, high tensile strength alloys, and stainless steel. The mechanics length — shorter than a jobber bit — provides added rigidity in tight spaces and reduces deflection during drilling. It is appropriate for use in drill presses, magnetic drills, and hand drills equipped with a Weldon-style chuck or adapter. Right-hand cut rotation is standard.

Key Features

• 21/64 inch diameter with 0.3281 inch decimal equivalent for precise sizing
• 135-degree split point self-centers and reduces thrust required to start a hole
• High-speed steel construction handles friction and heat in metal-cutting applications
• Three-flat Weldon shank prevents bit rotation and slipping in the chuck
• Web-thinned parallel web reduces cutting resistance and improves chip evacuation
• Oxide coating provides light surface protection and corrosion resistance
• Right-hand spiral flutes for standard clockwise drilling operation

Compatibility

Designed for use with Weldon-shank compatible chucks and holders. Suitable for drilling carbon steel, cast iron, high alloy steel, high tensile strength alloys, and stainless steel workpieces in general-purpose applications.

Installation Notes

Installation and use should be performed by a qualified machinist or maintenance technician familiar with metal drilling operations. Ensure the Weldon flat is properly seated against the set screw in the chuck or holder before operation to prevent slippage. Always secure the workpiece before drilling and wear appropriate eye and hand protection. Operate at a spindle speed appropriate for the material and diameter being drilled per standard machining references.