Precision Twist Drill 5996557 Cobalt Screw Machine Drill Bit

Product Description

The PRECISION TWIST DRILL 5996557 is a cobalt screw machine length drill bit engineered for drilling into hard materials where standard high-speed steel bits fall short. It measures 0.413 inches (Letter Size Z) in diameter with a 3.375-inch overall length and a 2-inch flute length. The 135-degree split point reduces walking on contact and lowers the thrust force needed to start the hole. A tapered web with web thinning keeps the cutting geometry aggressive through the full depth of cut. This bit is built to ANSI standards and carries an M42 cobalt material grade, making it a heavy-duty tool suited for machinists, maintenance technicians, and metalworking professionals.

Screw machine length bits are shorter than jobber-length bits, which increases rigidity and reduces deflection in turret lathes, drill presses, and CNC screw machine setups. The reduced length is also practical for tight-clearance hand-drilling applications on hard steels, stainless, high-nickel alloys, and similarly tough workpiece materials. The straight cylindrical shank fits standard drill chucks without adapters. The regular spiral flute with a 2.5xD flute-to-diameter ratio promotes chip evacuation in short-hole applications on hard stock.

Key Features

• M42 cobalt construction rated for hard material drilling including stainless and high-alloy steels
• 135-degree split point reduces entry thrust and minimizes bit walking on hard surfaces
• Screw machine length body increases rigidity and reduces deflection compared to jobber-length bits
• Tapered web with web thinning maintains cutting efficiency and reduces heat buildup
• Right-hand cut, regular spiral flute promotes consistent chip removal
• Built to ANSI standards for dimensional consistency across tooling setups

Compatibility

Designed for use in standard drill chucks accepting a straight cylindrical shank. Part of the M42CO Series, intended for high-performance drilling in hard and abrasion-resistant workpiece materials.

Installation Notes

Installation and use should be performed by qualified machinists or metalworking technicians familiar with drill press, lathe, or CNC machine operation. Secure the workpiece and verify chuck tightness before initiating the cut. Appropriate cutting fluid or coolant is recommended when drilling hard materials to extend tool life, even though this bit does not support through-coolant delivery. Follow all applicable machine shop safety protocols including eye protection and proper spindle speed selection for the workpiece material and bit diameter.