Precision Twist Drill 5998985 Taper Length Drill Bit

Product Description

The PRECISION TWIST DRILL 5998985 is a taper length drill bit designed for precise, clean drilling in non-ferrous metals and soft materials. Built from high speed steel (HSS) with a bright, uncoated finish, it features a 118-degree standard point angle and a right-hand spiral flute with a fast spiral type. At 0.1250 inches (1/8 inch) in diameter, this bit delivers a 6xD flute-to-diameter ratio, giving it extra reach compared to jobber-length bits. A web-thinned, tapered web configuration reduces entry resistance and improves chip evacuation. Licensed machinists, HVAC sheet metal fabricators, plumbers, and general trade mechanics use this bit for production and maintenance drilling alike.

This taper length drill bit is suited for drilling aluminum, aluminum alloy, copper, magnesium, and magnesium alloy. The extended flute length of 2.75 inches and overall length of 5.125 inches make it a practical choice when standard jobber bits lack the reach required for deep-hole applications in light metals. The cylindrical shank fits standard three-jaw chucks on drill presses, hand drills, and milling machine setups without adapters. It conforms to ANSI standards and is rated as a general-purpose grade bit for shop and field use.

Key Features

• 1/8 inch (0.1250 inch) diameter with matching 0.1250 inch cylindrical shank for direct chuck mounting
• 118-degree standard point angle with web-thinned, tapered web for reduced thrust and cleaner entry
• Fast spiral flute design promotes aggressive chip evacuation in aluminum and copper
• 2.75 inch flute length at a 6xD ratio provides extended reach beyond standard jobber length
• Bright, uncoated HSS construction — suitable for general-purpose drilling without coolant-through requirement
• ANSI-compliant Series R51FS geometry for consistent dimensional accuracy

Compatibility

Designed as a general-purpose taper length drill bit compatible with aluminum, aluminum alloy, copper, magnesium, and magnesium alloy workpieces. Fits any standard three-jaw chuck accepting a 0.1250 inch cylindrical shank.

Installation Notes

Secure the shank fully in a properly sized chuck before drilling; partial engagement reduces concentricity and accelerates shank wear. Disconnect or de-energize the drill press or power tool before changing bits. Use appropriate cutting fluid or lubricant when drilling copper to extend bit life, even though coolant-through is not required. Inspect the point and flutes for wear or chipping before each use — a dull or chipped 118-degree point will work-harden aluminum and degrade hole quality.