Which tool is commonly used for elevator installation?

The plumb bob is an essential tool used during elevator installation because it provides a reliable means of determining a true vertical line. Ensuring that components of the elevator, such as guide rails or hoist beams, are perfectly vertical is crucial for the elevator's proper operation. Any deviation from vertical alignment can lead to improper functioning, potential safety hazards, and increased wear on the elevator's mechanical systems.

Using a plumb bob involves suspending a weight from a string, allowing it to point directly to the ground and create a reference that indicates true verticality. This accuracy is vital in elevator systems, where precise alignment is critical for safety and performance.

In contrast, while a leveling gauge and torque wrench serve significant roles in ensuring level surfaces and proper fastener tightness respectively, they do not specifically address the need for vertical alignment as effectively as the plumb bob does. A sledgehammer, on the other hand, is generally not applicable for precise installation tasks like vertical alignment.