Hertel 74131236 Screw Machine Drill Bit Letter L Cobalt

Product Description

The HERTEL 74131236 is a cobalt screw machine length drill bit sized to Letter L (0.290 inches decimal) for right-hand cutting in short-reach, high-torque drilling applications. The 135-degree split point reduces walking and lowers thrust force at entry, making it well suited for work on harder metals and stainless steel. A web-thinned, parallel-web construction keeps the cutting edge geometry consistent as the bit is resharpened. At 2.75 inches overall length with a 1.5625-inch flute length, this stub-length bit delivers added rigidity compared to jobber-length alternatives, reducing deflection in production drilling setups.

Screw machine length bits are standard in CNC machining centers, drill presses, and turret lathes where spindle clearance is limited and rigidity is a priority. The HERTEL 74131236 fits production environments drilling carbon steel, alloy steel, cast iron, and work-hardened stainless. It is also used in manual drill press work where bit flex or chatter is a concern. The straight cylindrical shank seats directly in standard drill chucks and collet systems without adapters.

Key Features

• Letter L size - 0.290 inches decimal equivalent for precise hole sizing
• 135-degree split point reduces thrust and eliminates center-punch requirement on most metals
• Cobalt construction provides heat and wear resistance beyond standard HSS for harder workpiece materials
• Web-thinned parallel web maintains cutting efficiency and supports resharpening
• Screw machine (stub) length adds rigidity and reduces deflection versus jobber-length bits
• Regular spiral flute with right-hand cutting direction - compatible with standard spindle rotation

Compatibility

Designed as an OEM-style screw machine length drill bit for use in standard drill chucks and collet holders accepting a straight cylindrical shank in the 0.2500 to 0.3000 inch drill bit size range.

Installation Notes

Installation and use of this drill bit should be performed by a machinist or qualified trade professional. Secure the straight shank fully in the chuck or collet before operation and verify runout is within acceptable limits for the application. Always power down and lock out the spindle before changing bits. Do not exceed the recommended surface footage for cobalt tooling on the workpiece material being drilled.