M.a. Ford. 20403900 Carbide Drill Bit No. 61 0.0390 in

Product Description

The M.A. FORD. 20403900 is a solid carbide jobber length drill bit sized to No. 61 wire gauge (0.0390 inches decimal), designed for precision drilling in hard and abrasive materials. The 118-degree faceted point provides positive centering and clean entry, while the web-thinned, tapered-web geometry reduces thrust and improves chip evacuation. With a bright (uncoated) finish and regular spiral flute, this bit is suited for general-purpose drilling where dimensional accuracy is critical. It is sold individually and intended for use in CNC machining centers, drill presses, and precision hand-held equipment. Licensed machinists and tooling technicians are the primary installers and users.

This drill bit is appropriate for small-hole drilling applications in metalworking, electronics manufacturing, tooling, and precision fabrication. The straight-cylindrical shank seats securely in standard collets and drill chucks. The 0.0390-inch diameter and tight tolerance of -0.0005 to 0.0000 inches make it suitable for close-tolerance hole work in steel, aluminum, brass, plastics, and composite materials. The short 0.5-inch flute length and 1.5-inch overall length are optimized for rigidity and runout control in small-diameter drilling.

Key Features

• Solid carbide construction for rigidity and wear resistance in hard and abrasive materials
• No. 61 wire size, 0.0390-inch decimal diameter with tight tolerance (-0.0005 to 0.0000 inches)
• 118-degree faceted drill point with web thinning for reduced entry thrust
• Regular spiral flute with tapered-web configuration for efficient chip removal
• Bright finish - no coating that could affect hole diameter or chip flow
• Straight-cylindrical shank compatible with standard collets and drill chucks

Compatibility

Designed as a general-purpose solid carbide jobber drill for use in standard drill chucks and collet systems accepting a 0.0390-inch straight-cylindrical shank. Suitable for a wide range of machine tools including CNC machining centers and bench-top drill presses within the 0.0000 to 0.0500-inch small-diameter drill size range.

Installation Notes

Install in a properly sized collet or drill chuck rated for the 0.0390-inch shank diameter; verify concentricity and minimize runout before drilling. Ensure the spindle and workpiece are fully secured before engaging the drill. Solid carbide is brittle - avoid lateral loading, interrupted cuts without proper feed rates, and re-chucking a bent or damaged bit. Follow shop safety practices and machine manufacturer guidelines for small-diameter tooling speeds and feeds.