Precision Twist Drill 5998278 Wire 75 Hss Drill Bit

Product Description

The PRECISION TWIST DRILL 5998278 is a jobber-length drill bit sized to wire gauge 75, with a decimal diameter of 0.0210 inches. It is manufactured from high speed steel with a bright uncoated finish and a standard 118-degree split point. The bit features a spiral, regular-helix flute with web thinning applied at the tip for cleaner entry and reduced thrust. Overall length is 1 inch, with a straight-cylindrical shank of equal diameter at 0.0210 inches. The two-flute design handles general-purpose drilling in steel, cast iron, non-ferrous metals, superalloys, and titanium. Machinists, tool-and-die technicians, and precision fabricators are the primary users of bits in this size range.

This bit is suited for light-duty precision drilling applications where very small hole diameters are required. Typical use cases include instrument assembly, electronics fabrication, small-part machining, and prototype work. The maximum drilling depth is 0.25 inches (1/4 inch), and the flute length matches that depth at 0.25 inches. The flute-to-diameter ratio of 12xD supports accurate chip evacuation in shallow, small-bore holes. No coolant-through capability is present, so external cooling or pecking cycles are recommended when drilling harder alloys. This bit ships individually and is sold in minimum order quantities of 12 units.

Key Features

• Wire gauge 75 size, 0.0210-inch decimal diameter for precision small-bore drilling
• High speed steel construction rated for steel, cast iron, non-ferrous metals, superalloys, and titanium
• 118-degree standard point angle with web thinning for reduced entry thrust
• Spiral regular-helix flute, 0.25-inch flute length, 12xD flute-by-diameter ratio
• Straight-cylindrical shank, 0.0210-inch diameter, 0.75-inch shank length
• Bright uncoated finish; ANSI specification compliant; Series R10H-R18H

Compatibility

Designed as a general-purpose jobber-length replacement or production bit for any standard drill chuck or collet accepting a 0.0210-inch straight-cylindrical shank, conforming to ANSI standards for wire-gauge drill bits.

Installation Notes

Secure the shank fully in a drill chuck or collet rated for the spindle speed appropriate to the workpiece material and bit diameter. At this diameter, spindle speeds are typically high and feed pressure must be minimal to avoid bit breakage. Power down the machine and lock out the spindle before changing or inspecting the bit. When drilling harder alloys such as superalloys or titanium, use a pecking cycle and external cutting fluid to manage heat and chip evacuation in the absence of coolant-through capability.