Threaded Drill Bits, 1/4

Threaded Shank Cobalt Drill Bits for Aircraft Maintenance

Threaded shank cobalt drill bits are designed for aircraft maintenance applications where a secure, compact drill-bit connection and reliable cutting performance are important. These drills feature an industry-standard 1/4-28 threaded shank and are manufactured to NAS 965 Type D Standards with a 135-degree split point.

The threaded-shank design allows the drill to be installed into compatible threaded drill adapters and aircraft maintenance drilling systems. Compared with conventional straight-shank drills, the threaded connection provides a compact setup that is well suited to the confined spaces and specialized tooling commonly encountered during aircraft maintenance.

Cobalt alloy drill bits are selected for demanding drilling applications because of their hardness, heat resistance, and ability to maintain cutting performance when drilling tough, high-strength materials. These characteristics make threaded cobalt drills a valuable option for aviation maintenance, repair, and overhaul operations.

1/4-Inch Threaded Drill Bit Sizes & Lengths

The 1/4-inch threaded drill bit is available in three lengths to accommodate different aircraft maintenance applications and access requirements. Select the length appropriate for the drilling location and the applicable maintenance procedure.

Why Use Threaded Shank Drill Bits?

Aircraft maintenance often requires drilling in confined areas where tool size, access, and drill control are important. A threaded shank drill bit eliminates the need for a conventional chuck-style shank connection when used with a compatible threaded adapter, creating a compact and secure drilling setup.

• 1/4-28 threaded shank: Uses the industry-standard 1/4-28 thread for compatibility with appropriate threaded drill adapters.
• Cobalt construction: Provides increased heat resistance and durability for demanding drilling applications.
• 135-degree split point: Helps the drill start accurately and reduces the tendency for the bit to walk when beginning a hole.
• NAS 965 Type D: Manufactured to the dimensional and performance requirements associated with NAS 965 Type D threaded shank adapter drills.
• Multiple lengths: Long, short, and stub configurations allow technicians to select a drill appropriate for the available working space.

Threaded Shank Drill Bits for Aircraft Maintenance

Threaded shank cobalt drills are commonly used in aircraft maintenance environments for drilling operations involving tough, high-strength materials. Cobalt drill bits are particularly well suited to applications where heat generation and tool wear are concerns.

Aircraft structures and components can incorporate materials such as titanium alloys, stainless steel, and other high-strength materials. The cobalt construction of these drills provides the heat resistance and durability needed for demanding drilling operations when the correct cutting conditions and procedures are followed.

Choosing the Correct Threaded Drill Bit Length

Choosing the correct overall length is important when drilling aircraft components. A longer drill provides additional reach, while a short or stub drill can provide a more compact setup and improved access in confined areas.

BAC offers the 1/4-inch threaded drill bit in 2-1/8-inch long, 1-1/4-inch short, and 9/16-inch stub configurations. Select the shortest drill that provides adequate access for the application whenever practical.

Threaded Drill Bits vs. Conventional Drill Bits

Conventional aircraft drill bits typically use a standard straight shank that is held in a drill chuck or collet. Threaded shank drill bits instead use a threaded connection designed for a compatible adapter or drill system.

The primary advantage of the threaded design is the ability to create a compact drilling setup while maintaining a secure connection. This can be particularly useful in aircraft maintenance applications where access to the work area is restricted.

Aircraft Materials & Drilling Applications

Cobalt threaded drill bits are suited to demanding drilling applications involving hard and high-strength materials. Depending on the aircraft, component, and approved maintenance procedure, applications may include drilling aircraft structure, preparing fastener holes, component installation, repair work, and other precision drilling operations.

Always use the drill size, cutting parameters, tooling, and technique specified by the applicable aircraft maintenance manual, structural repair manual, engineering instruction, or other approved procedure.

Threaded Shank Cobalt Drill Bit Specifications