Final answer:
A keyless chuck, referred to as a hand chuck, should only be tightened using hand to prevent damage and ensure ease of later releasing the bit.
Step-by-step explanation:
A keyless chuck is called a hand chuck and should only be tightened by hand. Hand chucks are designed for convenience and ease of use, allowing users to secure and release drill bits or other attachments without the need for a separate tool, like a chuck key. The correct way to tighten a hand chuck is by holding the base with one hand and turning the sleeve where the bit is inserted with the other hand until the jaws of the chuck firmly grip the bit. It is important not to use tools to tighten a keyless chuck because they can apply excessive force which might damage the chuck or make it difficult to release the bit later on.