Precision Twist Drill 5998478 3/8 in Screw Machine Drill Bit

Product Description

The PRECISION TWIST DRILL 5998478 is a screw machine length drill bit designed for high-performance metal drilling in industrial and trade applications. It measures 3/8 inch (0.3750 inches) in diameter with an overall length of 3.125 inches and a flute length of 1.8125 inches. The bit is manufactured from high speed steel with a bright/uncoated finish and features a standard 118-degree point angle with web thinning for easier penetration and reduced thrust. The straight-cylindrical shank seats securely in standard drill chucks. This is a Series R40 bit built to ANSI standards and suited for machinists, maintenance technicians, and production drilling professionals.

The 5998478 is rated for drilling titanium as its primary workpiece material, making it well-suited for demanding applications where tool performance and edge retention matter. The screw machine length format — shorter than a jobber bit — provides added rigidity and reduces deflection in tight workspaces, turret lathes, and drill press setups. The 2.5xD flute-to-diameter ratio supports effective chip evacuation at moderate feed rates. This bit fits standard drill presses, CNC machining centers, manual lathes, and handheld drills with compatible chucks. It is packaged and sold individually.

Key Features

• 3/8 inch diameter with a 118-degree standard point angle and web thinning for reduced entry thrust
• High speed steel construction provides heat resistance and edge retention during metal drilling
• Screw machine length format adds rigidity and minimizes deflection compared to jobber-length bits
• Bright/uncoated finish for general purpose use across a range of ferrous and non-ferrous materials
• Right-hand cut with regular spiral flute for efficient chip removal
• Meets ANSI standards; Series R40 designation for consistent dimensional accuracy

Compatibility

Designed as a general purpose screw machine length replacement drill bit compatible with standard straight-shank drill chucks across drill presses, turret lathes, and CNC machining centers rated for 3/8 inch shank tooling.

Installation Notes

Installation of this drill bit should be performed by a qualified machinist or trade technician. Ensure the spindle is fully stopped and the machine is powered off before inserting or removing the bit from the chuck. Secure the shank firmly in the chuck and verify concentricity before beginning a cut. Always use appropriate cutting fluid or coolant for the workpiece material to extend tool life and maintain surface finish quality.