Precision Twist Drill 5999656 Cobalt Jobber Drill 1.55mm

Product Description

The PRECISION TWIST DRILL 5999656 is a cobalt high-speed steel jobber-length drill bit designed for general-purpose drilling in ferrous and non-ferrous metals. It measures 1.55 mm (0.0610 inches) in diameter with an overall length of 1-11/16 inches (43 mm). The 135-degree split point reduces walking on entry and lowers the thrust force needed to start a hole. An oxide and straw finish provides light lubricity and corrosion resistance during dry or minimal-lubrication drilling. The web-thinned, tapered web design improves chip evacuation. This bit is built to DIN 338 and ANSI standards, making it a reliable choice for machinists, maintenance technicians, and metalworking tradespeople.

The 5999656 is suited for drilling steel, stainless steel, cast iron, aluminum, and non-ferrous alloys, consistent with its P, M, K, N, and S workpiece material codes. With a 13xD flute-to-diameter ratio and a 25/32-inch (20 mm) flute length, it handles drilling depths up to 0.7874 inches in a single pass. The straight cylindrical shank fits standard drill chucks without adapters. This bit is typically used in CNC drilling operations, drill presses, and hand drills where small-diameter, tight-tolerance holes are required in metal fabrication and maintenance environments.

Key Features

• Cobalt HSS construction rated for heavy-duty drilling in hardened and abrasive steels
• 135-degree split point for reduced walking and lower entry thrust
• Web-thinned tapered web improves chip flow and reduces heat buildup
• Oxide and straw finish provides light lubricity without external coating buildup
• Straight cylindrical shank fits standard drill chucks with no adapter required
• Manufactured to DIN 338 and ANSI standards for consistent dimensional tolerances

Compatibility

Designed as a general-purpose jobber drill bit compatible with standard drill chucks accepting a 1.55 mm (0.0610-inch) straight shank. Suitable for workpiece materials coded P, M, K, N, and S, covering steel, stainless steel, cast iron, aluminum, and non-ferrous alloys per DIN 338 classification.

Installation Notes

Install and replace drill bits with all power sources locked out and the machine at a full stop. Seat the straight shank fully in the chuck and tighten evenly using the chuck key before starting the spindle. When drilling hard steels with a cobalt bit, use a cutting fluid or cutting oil to extend tool life and maintain hole quality. Inspect the cutting edges and point geometry before each use; a chipped or worn point will produce oversize holes and increase the risk of bit breakage at small diameters.