Precision Twist Drill 5995988 Cobalt Drill Bit No.19

Product Description

The PRECISION TWIST DRILL 5995988 is a high-performance cobalt aircraft extension drill bit designed for drilling tough materials where standard HSS tooling falls short. Built to Series CO501-6 specifications, this bit features a 135-degree split point that is self-centering and web-thinned, reducing walking and thrust on entry. The 0.166-inch diameter straight-cylindrical shank fits standard drill chucks without adapters. The straw finish indicates a heat-treatment process consistent with cobalt alloy tooling. Right-hand spiral flutes with a 4xD flute-to-diameter ratio clear chips efficiently during deep-hole operations. This bit is sized to No. 19 wire gauge and is sold individually.

The CO501-6 series is intended for aerospace, maintenance, and fabrication applications where extended reach is required and hole quality must be consistent. The 2.125-inch flute length and 6-inch overall length allow access to recessed locations that standard-length bits cannot reach. Typical users include aircraft maintenance technicians, structural fabricators, and industrial maintenance mechanics working with aluminum, stainless steel, titanium, and other hard alloys. The 135-degree split point geometry reduces the need for a center punch on most metals.

Key Features

• Cobalt tool material provides heat and wear resistance beyond standard HSS for hard and abrasive materials
• 135-degree split point is self-centering and web-thinned for reduced thrust and clean entry
• 6-inch overall length with 2.125-inch flute length gives extended reach into deep or recessed workpieces
• Straw finish applied post-grind as standard cobalt treatment
• Tapered web configuration with 4xD flute ratio supports chip evacuation in deeper holes
• Meets NAS 907 Type J standards for aircraft drilling applications

Compatibility

Designed as a Series CO501-6 aircraft extension drill bit for use in standard straight-shank drill chucks. Meets NAS 907 Type J standards applicable to aerospace and industrial drilling operations.

Installation Notes

This bit is installed by trade machinists, aircraft maintenance technicians, and industrial mechanics using standard drill motors or drill presses with straight-shank chucks. Secure the workpiece before drilling and confirm chuck runout is within acceptable limits to preserve bit geometry and hole tolerance. Use appropriate cutting fluid for the base material to extend tool life. Inspect the split point and cutting edges before each use and replace the bit if chipping or dulling is observed.