Which of the following is a common pneumatic tool used during mechanical fastening?

A nail gun is indeed a common pneumatic tool used in various fastening applications, particularly for driving nails into materials quickly and efficiently. Pneumatic nail guns utilize compressed air to forcefully drive nails, making them ideal for tasks requiring speed and precision, such as framing or roofing in construction projects.

In the context of the options presented, the nail gun stands out as a specialized tool designed specifically for fastening with nails, making it a clear choice among commonly used pneumatic tools.

The impact wrench, while a pneumatic tool, is primarily associated with driving bolts and nuts rather than nails, and is typically used in automotive or heavy machinery contexts. The screwdriver, while essential for fastening screws, is not a pneumatic tool and operates manually or with electric power. Similarly, although drills can also be used for fastening, they are generally not classified as pneumatic tools unless specifically designed for that purpose. Thus, the functionality and design of the nail gun align it closely with the needs of mechanical fastening using pneumatic power.