Precision Twist Drill 5998905 Taper Length Drill Bit

Product Description

The PRECISION TWIST DRILL 5998905 is a taper length high speed steel drill bit designed for precise through-hole drilling in metalworking and fabrication applications. It measures 0.3125 inches (5/16 inch) in diameter with a 4-inch flute length and a 6.375-inch overall length. The 118-degree standard point geometry and web-thinned, tapered web configuration reduce entry force and improve centering accuracy. The bright, uncoated finish is well suited for general-purpose drilling where lubrication is applied at the point of use. This bit is part of the Series R51FS line and conforms to ANSI standards.

This drill bit is intended for use in aluminum, aluminum alloy, copper, magnesium, and magnesium alloy workpieces. The right-hand spiral flute design efficiently evacuates chips during drilling operations. It fits drill presses, lathes, milling machines, and hand-held power drills accepting a cylindrical shank. Machinists, pipefitters, plumbers, and HVAC sheet metal fabricators commonly use taper length bits when extra flute length is needed to clear deep holes that standard jobber bits cannot reach.

Key Features

• 0.3125-inch (5/16-inch) diameter cylindrical shank with no threading
• 118-degree standard point angle for general-purpose drilling
• 4-inch spiral flute length provides a 6xD flute-to-diameter ratio for deep-hole chip clearance
• Web-thinned, tapered web reduces thrust and improves drill entry
• Bright, uncoated high speed steel construction — compatible with cutting fluid application
• Right-hand cut; ANSI-compliant Series R51FS

Compatibility

Rated for use in aluminum, aluminum alloy, copper, magnesium, and magnesium alloy materials. Fits any chuck or drill holder accepting a 0.3125-inch cylindrical shank.

Installation Notes

A licensed machinist or qualified tradesperson should secure the bit firmly in a properly sized chuck before operation. Always power down and de-energize the drill or machine before changing bits. Use an appropriate cutting fluid for the workpiece material to extend tool life and improve hole quality. Inspect the cutting edges for wear or chipping before each use and replace the bit if the point is damaged.