Which key is designed specifically to be sunk into a part in one being machined?

• A. Nose Key
• B. Double-Nose Sunk Key
• C. Boat Key
• D. Gib-Head Taper Key

Answer: (B)

The double-nose sunk key is specifically engineered to be inserted into a part during machining processes, making it ideal for applications requiring a tight fit and reliable torque transmission. This type of key features narrow leading and trailing edges, which allows it to be recessed into the part, thereby minimizing any protrusion and providing a clean, flush finish.

The design of the double-nose sunk key facilitates efficient machining and assembly while also helping to reduce the risk of wear and failure in applications where high torsional loads may be encountered. This key effectively locks components together while streamlining the overall design of the assembly, making it a preferred choice in mechanical engineering contexts.

In contrast, other options like the gib-head taper key or boat key may serve different functions, such as providing a wedge effect to tighten or secure components, but they are not specifically meant for sinking into a machined part in the same manner as the double-nose sunk key.