Precision Twist Drill 5998521 Screw Machine Drill Bit

Product Description

The PRECISION TWIST DRILL 5998521 is a screw machine length drill bit designed for high-performance drilling in demanding trade and industrial applications. Built from high speed steel (HSS) with a coated finish, this bit features a 135-degree split point and web-thinned, tapered web configuration for fast penetration and reduced walking at startup. It measures 0.166 inches (wire size No. 19) in diameter with an overall length of 2.125 inches and a flute length of 1.0625 inches. The right-hand spiral flute geometry and straight-cylindrical shank make it compatible with standard drill chucks and machine spindles. This is a heavy duty grade bit rated to ANSI and NAS 907 specifications.

This drill bit is suited for screw machine, CNC drilling, and manual drill press operations where short-length rigidity is required. The primary workpiece material designation is titanium, making it appropriate for hard-metal fabrication, aerospace component work, and precision machining tasks where standard bits lose edge life quickly. The 2.5xD flute-to-diameter ratio supports chip evacuation in shallow-to-moderate depth holes. Machinists, tool and die technicians, and sheet metal fabricators working with titanium and similar hard alloys will find this bit appropriate for production drilling at close tolerances. It is sold as a single bit per package with a minimum order quantity of 12 units.

Key Features

• 135-degree split point with web thinning reduces thrust and prevents bit walking on hard materials
• High speed steel construction with coated finish extends edge life in titanium and hard-metal applications
• Screw machine length body provides added rigidity compared to jobber length bits
• Straight-cylindrical shank fits standard drill chucks and machine tool spindles without adapters
• Meets ANSI and NAS 907 specifications for dimensional and performance consistency
• Right-hand spiral flute promotes efficient chip clearance during through-hole and blind drilling

Compatibility

Designed as an OEM-style replacement or direct production substitute for screw machine length HSS drill bits in the 0.150 to 0.200 inch diameter range, Series R41C.

Installation Notes

Installation of this drill bit should be performed by a qualified machinist or tool operator familiar with cutting tool setup. Ensure the machine spindle or drill chuck is fully powered down and locked out before inserting or removing the bit. Secure the straight-cylindrical shank fully into the chuck to the recommended grip depth to prevent runout or pullout during operation. Coolant-through is not supported on this bit, so external coolant or cutting fluid should be applied at the workpiece when drilling titanium or other high-strength materials to manage heat buildup and preserve edge life.