Why is a sunk key provided with a gib head?

• A. To fit easily
• B. To remove easily
• C. To transmit shock
• D. All of these

Answer: (B)

A sunk key is designed with a gib head primarily to facilitate easy removal from the shaft or the hub of the connected parts. The gib head assists in applying leverage during the extraction process, allowing for a simple and efficient way to disengage the key from its position. This design helps to mitigate damage to the key and the keyway, making maintenance and repairs more manageable.

While the other options suggest potential benefits, such as fitting easily or transmitting shock, they do not address the central purpose of the gib head design. The easy removal highlighted in the correct choice is the key reason for using a sunk key with a gib head, ensuring that the mechanism can be maintained or adjusted without excessive difficulty or damage.