Which tool is primarily used for gripping and holding objects tightly?

The tool primarily used for gripping and holding objects tightly is groove joint pliers. These pliers, often called slip joint pliers, feature adjustable jaws that allow the user to grip various sizes of objects securely. They have a series of grooves in the pivot point, enabling the jaws to open wider or close tighter as needed. This feature makes them ideal for tasks that require a strong, non-slip grip on pipes, fittings, or other irregularly shaped objects, which is essential for ensuring precision and safety during work.

In contrast, the other options serve different purposes. A half hatchet is designed primarily for chopping and splitting wood, making it unsuitable for gripping tasks. Hedge shears are specifically used for trimming hedges and bushes, focusing on cutting rather than holding. A hammer drill is designed for drilling into hard materials and does not have a gripping function at all. Therefore, groove joint pliers stand out as the best choice for gripping and holding objects tightly.