Hertel C.E07.0258 Aircraft Extension Drill Bit 38 Cobalt

Product Description

The HERTEL C.E07.0258 is a cobalt aircraft extension drill bit designed for drilling in tight-clearance and deep-reach applications where a standard-length bit cannot access the worksite. Built to wire size 38, with a decimal diameter of 0.1015 inches and an overall length of 12 inches, this bit is suited for aerospace, sheet metal, and structural fabrication work. The 135-degree split point is self-centering and reduces walking on entry, eliminating the need for a center punch on most materials. A straw finish indicates the cobalt-alloy construction has been heat-treated, making it appropriate for harder steels and stainless alloys. Machinists, aircraft maintenance technicians, and metalworking tradespeople are the primary installers.

This drill bit is used in applications where extended reach is required to access recessed or deep structural members, such as aircraft airframe repair, heavy equipment fabrication, and industrial maintenance drilling. The spiral flute design clears chips efficiently during through-drilling in metal. The straight cylindrical shank seats directly in standard drill chucks without adapters. Its general-purpose performance rating makes it appropriate for mild steel, alloy steel, and similar ferrous materials common in trade and aerospace maintenance environments.

Key Features

• Wire size 38 (0.1015 inches) for precision small-diameter drilling
• 12-inch overall length provides extended reach into deep or restricted spaces
• 135-degree split point is self-centering and web-thinned for reduced feed force
• Cobalt tool material with straw finish withstands elevated cutting temperatures
• Right-hand spiral flute with tapered web configuration improves chip evacuation
• Meets NAS 907 standard for aircraft-quality drill bits

Compatibility

Designed as an OEM-style replacement or direct-use drill bit for applications requiring wire size 38 aircraft extension bits with a straight cylindrical shank in any standard drill chuck or drill press setup.

Installation Notes

This bit is installed by machinists, aircraft maintenance technicians, or metalworking tradespeople using a standard keyed or keyless drill chuck. Secure the straight shank fully in the chuck before drilling and verify runout is within acceptable tolerance for the application. Use appropriate cutting fluid when drilling hardened or stainless steels to extend tool life. Inspect the cutting edges before each use and remove the bit from service if chipping or heat discoloration beyond the straw zone is present.