What tool is most commonly used to tighten hydraulic fittings?

The most commonly used tool to tighten hydraulic fittings is a torque wrench. This tool is specifically designed to apply a specific amount of torque to fasteners, ensuring that they are tightened to the manufacturer's specifications. Proper torque is crucial in hydraulic applications because it helps maintain the integrity of the seal, preventing leaks and ensuring that the system operates efficiently under high pressure. Using a torque wrench helps to avoid over-tightening, which can damage components, or under-tightening, which can lead to failures in the hydraulic system.

In contrast, while a socket wrench might be used in some applications for general tightening, it does not allow for the precise torque measurement that is required for hydraulic fittings. A pipe wrench is typically used for gripping and turning pipes and is not suitable for sensitive hydraulic fittings due to its potential to damage the fitting's surfaces. A standard screwdriver is not applicable for hydraulic fittings, as these fittings do not utilize screws that would fit a screwdriver. Thus, the torque wrench is the ideal choice for this specific task.