Precision Twist Drill 5998938 Screw Machine Drill Bit

Product Description

The PRECISION TWIST DRILL 5998938 is a screw machine length drill bit designed for high-performance drilling in metalworking and machining applications. Built from high speed steel with a bright, uncoated finish, this bit measures 0.29 inches in diameter and carries a letter size designation of L. The 118-degree standard point angle and web-thinned, tapered web configuration reduce entry force and improve chip clearance. With a right-hand spiral flute and straight-cylindrical shank, it is sized and configured for use in standard drill chucks and screw machine setups. Licensed machinists and shop technicians are the primary installers.

This bit is suited for production drilling in screw machine operations and general-purpose machine shop environments. The R42 series targets high-performance cutting with a 2.5xD flute-to-diameter ratio, making it effective for drilling titanium and other demanding primary workpiece materials. The compact screw machine length overall length of 2.75 inches keeps the bit rigid and minimizes deflection in tight-clearance drilling setups. It conforms to ANSI standards and is appropriate for both light production and maintenance machining work.

Key Features

• 0.29-inch diameter, letter size L, screw machine length for rigid, low-deflection drilling
• High speed steel construction rated for general-purpose and high-performance machining
• 118-degree standard point angle with web-thinned, tapered web for reduced entry force
• Right-hand cut, regular spiral flute for efficient chip evacuation
• Straight-cylindrical shank compatible with standard drill chucks
• Meets ANSI standards; no coolant-through required

Compatibility

Designed as an OEM-style screw machine length drill bit in the R42 series, suitable for use with standard drill chucks accepting straight-cylindrical shanks; rated for drilling titanium and general metalworking materials in the 0.2500 to 0.3000-inch diameter range.

Installation Notes

Installation is performed by machinists or tool and die technicians using standard drill press, lathe, or CNC screw machine equipment. Ensure the chuck and spindle are fully stopped and locked out before inserting or changing the bit. Secure the shank firmly in the chuck to the full depth of the flats to prevent slippage during cutting. Follow shop safety protocols and applicable ANSI machining standards when selecting feeds and speeds for the workpiece material.