The lever class of a hammer depends upon its use. If the hammer is used as a claw to remove a nail, it is a first class lever. When the hammer is used to strike a nail, it is a third class lever.
There are three classes of levers. The difference between the classes lies in the position of the load, the effort and the fulcrum. When the fulcrum is between the load and effort, the object is a first class lever. If the load is between the fulcrum and effort, the object is a second class lever. A third class lever places the effort between the load and the fulcrum.