What happens if a rivet gun is too light?

When a rivet gun is too light, it tends to produce insufficient force to properly set the rivet. This lack of adequate force can lead to work hardening of the rivet material prematurely. Work hardening is a process where the material becomes more brittle and susceptible to cracking or breaking as it is compressed and deformed. If the rivet does not receive enough energy to flow properly into the joint, the rivet may harden before it is fully deformed into place, compromising the integrity of the joint.

In contrast, the effects of a rivet gun that is too light include driving rivets too slowly or causing uneven countersinks, but these outcomes are secondary to the potential risk of the rivet work hardening too soon. Proper riveting requires the correct application of force to ensure the rivet is adequately formed while maintaining its material properties, thus allowing for effective structural integrity in the aircraft.