Hertel 74148891 Screw Machine Drill Bit 15/64 in Carbide

Product Description

The HERTEL 74148891 is a screw machine length drill bit ground from solid carbide and designed for demanding material removal in short, rigid setups. At 15/64 inches (0.2344 inches decimal) in diameter, it features a 135-degree split point that reduces walking and lowers thrust on entry, making it well-suited for production drilling without a center punch. The slow spiral flute geometry controls chip evacuation in tough workpiece materials, and the bright uncoated finish keeps the carbide substrate exposed for full hardness at the cutting edge. A parallel web configuration with web thinning further reduces cutting resistance. The overall length is 2-7/16 inches with a 1-5/16-inch flute length, and the straight cylindrical shank seats directly in standard drill chucks or collet holders.

This bit is intended for right-hand cutting in hard and abrasive workpiece materials where high-speed steel tooling loses its edge too quickly. Primary workpiece materials listed by the manufacturer include cast iron, nickel alloy, stainless steel, titanium alloy, and tool steel. Screw machine length geometry keeps the bit short and stiff, reducing deflection in CNC machining centers, drill presses, and manual screw machines. It is a common choice in job shops, maintenance machining, and any production line drilling into difficult alloys. Diameter tolerance is held to +0.0000 to -0.0005 inches, supporting close-tolerance hole requirements.

Key Features

• Solid carbide construction for drilling cast iron, nickel alloy, stainless steel, titanium alloy, and tool steel
• 135-degree split point reduces drill walk and lowers feed pressure on entry
• Slow spiral flute design controls chip flow in stringy and hard materials
• Web-thinned parallel web reduces axial thrust during drilling
• Diameter tolerance of +0.0000 to -0.0005 inches for close-tolerance hole requirements
• Bright uncoated finish preserves full carbide hardness with no coating buildup at the cutting edge

Compatibility

Designed as a screw machine length replacement drill bit for use in standard drill chucks, collet holders, and tool holders accepting a straight cylindrical shank in the 0.2000 to 0.2500-inch diameter range.

Installation Notes

A licensed machinist or trained toolroom technician should verify spindle speed and feed rate for the specific workpiece material before use. Secure the shank fully in a collet or drill chuck rated for the shank diameter before starting the spindle. Solid carbide tooling is brittle and susceptible to chipping from interrupted cuts or side loading - do not use in hand-held drills. Inspect the cutting edges and point for chipping before each use and remove any coolant or chip buildup from the flutes after use.