What should not be used as a punch or a chisel?

Using a screwdriver as a punch or a chisel is inappropriate because it is not designed for that purpose. Screwdrivers have a specific function, primarily to turn screws, and using them as a punch can damage both the screwdriver and the material being worked on. Additionally, the structural integrity of a screwdriver is not suited to withstand the impact forces that come with striking it like a punch or chisel. This can lead to a higher risk of injury, as the screwdriver may snap or break, which can create sharp projectiles or cause loss of control during use.

In contrast, hammers, pliers, and wrenches, while they may not be the best choices for these applications, are tools that have been designed or can withstand external forces to some extent. Hammers are specifically made for striking, and although using pliers or a wrench as a punch or chisel is also not recommended, they are generally sturdier than a screwdriver for that particular application. Hence, the screwdriver stands out as the least suitable tool for such tasks.