Hertel 74131988 Drill Bit Letter Y Cobalt Tialn 135 Deg

Product Description

The HERTEL 74131988 is a screw machine length drill bit sized to Letter Y (0.4040 inches decimal equivalent), designed for high-productivity drilling in metalworking and machining applications. Built from cobalt high-speed steel and coated with TiAlN (titanium aluminum nitride), this bit handles elevated cutting temperatures and abrasive materials without rapid edge breakdown. The 135-degree split point reduces thrust load on entry and self-centers without a pilot hole. Overall length is 3-5/16 inches, keeping the bit rigid and reducing deflection in short-reach setups. Installation and operation are handled by machinists, tool-and-die professionals, and maintenance mechanics working on manual or CNC drill presses, mills, and lathes.

This bit is suited for production drilling in ferrous metals including alloy steels, stainless steel, cast iron, and hardened materials where standard HSS bits wear prematurely. The screw machine length profile - shorter than jobber length - provides added stiffness, making it the preferred choice for drill press work, turret lathes, screw machines, and CNC machining centers where tool overhang must be minimized. The right-hand spiral flute evacuates chips efficiently during through-hole and blind-hole drilling at standard to elevated feed rates.

Key Features

• Letter Y size - 0.4040 inches decimal equivalent for precise hole sizing
• Cobalt construction provides heat and wear resistance beyond standard HSS
• TiAlN coating extends tool life when cutting alloy steels and stainless
• 135-degree split point self-centers and reduces drill thrust on entry
• Screw machine (stub) length at 3-5/16 inches OAL improves rigidity and reduces deflection
• Web-thinned parallel web design lowers cutting resistance and improves chip flow

Compatibility

Designed for use in standard straight-shank drill chucks on drill presses, manual lathes, turret lathes, CNC machining centers, and screw machines accepting straight-cylindrical shank tooling in the 0.4000 to 0.4500 inch diameter range.

Installation Notes

Always power down and lock out the machine spindle before changing tooling. Secure the straight-cylindrical shank firmly in a properly sized drill chuck or collet to prevent slippage under load. Cobalt bits with TiAlN coating perform best with appropriate cutting fluid or coolant for the workpiece material - consult the material manufacturer or machining data reference for recommended speeds and feeds. Inspect the cutting edge and point for chipping or wear before each use; a damaged split point will cause off-center entry and oversize holes.