Precision Twist Drill 5997837 No. 77 Cobalt Jobber Drill

Product Description

The PRECISION TWIST DRILL 5997837 is a No. 77 wire-size jobber-length drill bit manufactured from cobalt high speed steel with a straw oxide finish. Sized at 0.0180 inches in diameter with a 0.875-inch overall length and a 0.1875-inch flute length, it is built for heavy-duty general-purpose drilling in ferrous and non-ferrous materials. The 135-degree split point and web-thinned tip reduce walking on entry and lower the thrust required to break through the workpiece. Licensed machinists, tool-and-die makers, and field technicians use this bit for precision small-diameter work in steel and other demanding materials.

This bit is suited for production and maintenance drilling applications where a wire-gauge No. 77 hole is required. The regular spiral flute geometry and right-hand cutting direction make it compatible with standard drill presses, CNC machining centers, and handheld power drills operating at appropriate spindle speeds for the 0.0180-inch diameter. Primary workpiece materials include steel, cast iron, non-ferrous alloys, and composite materials corresponding to material codes P, M, K, N, and S. The cobalt alloy construction handles elevated cutting temperatures better than standard high speed steel, making it well-suited for harder steel grades and interrupted cuts.

Key Features

• No. 77 wire size, 0.0180 inches diameter for precision small-hole drilling
• Cobalt high speed steel construction for improved heat and wear resistance
• 135-degree standard split point with web thinning reduces thrust and minimizes walking
• Straw oxide finish provides corrosion resistance and reduces friction at the cutting edge
• Regular spiral flute with tapered web for reliable chip evacuation
• Meets ANSI and NAS 907 standards for dimensional accuracy

Compatibility

Designed for use in the PRECISION TWIST DRILL Series R10CO-R15CO-R18CO and suited as a general-purpose No. 77 wire-size drill bit for any standard straight-shank drill chuck accepting a 0.0180-inch diameter shank.

Installation Notes

Installation of this bit requires a drill chuck rated for the 0.0180-inch straight cylindrical shank diameter. Secure the bit fully in the chuck before operating and verify spindle speed is appropriate for the workpiece material and bit diameter per standard machining tables. Secure the workpiece firmly before drilling to prevent movement during the cut. Inspect the cutting edges for wear or chipping before each use, as cobalt bits used at incorrect speeds or feeds can chip rather than wear gradually.