Which tool is primarily used for driving or fastening negative slotted screws?

The tool primarily used for driving or fastening negative slotted screws is the slotted screwdriver. This type of screwdriver has a flat blade that fits into the single slot of a negative slotted screw head. When using a slotted screwdriver, it is designed to allow for the proper torque and control needed to drive the screw effectively into place.

The slotted screwdriver's design is specifically intended to engage the screw's slot, ensuring that the energy applied is efficiently transferred to the screw, minimizing the risk of stripping the screw head. This characteristic makes it crucial for tasks requiring precision and effective fastening.

While alternative tools such as hex drivers or flathead screwdrivers may develop some functionality with certain types of screws, they are not optimized for slotted screws, which can lead to ineffective fastening and potential damage to the screw or tool. A torpedo level is unrelated to fastening screws, as it is designed for ensuring a level surface, confirming that its application is irrelevant in this context.