When adjusting the air pressure of a rivet gun, what should it be tested against?

The correct choice of testing the air pressure of a rivet gun against a block of wood relates to the practical requirements of ensuring that the gun delivers sufficient force for effective riveting. By using a block of wood, you can evaluate the compressive ability of the rivet gun in a controlled manner. Since wood is a material of known density and strength, it serves as an effective medium to gauge how well the rivet gun operates under expected working conditions.

Testing against a block of wood allows the user to observe the result of the riveting action directly, ensuring that the air pressure is set appropriately to not only drive the rivets but to prevent damage to the material being worked on.

While other materials like metal sheets can provide insights regarding force application, they may also risk damage and provide less feedback about the gun's performance compared to wood. A plastic board might not adequately mimic the resistance felt when riveting a metal surface, while testing against an air compressor gauge would only confirm the pressure levels but wouldn't illustrate their practical impact on riveting tasks. Therefore, a block of wood offers the balance of resistance and safety for testing adjustments effectively.