A hand tool used to beat or hammer objects. A hammer consists of a hammer head and a handle. ① Hammer head: made of steel, copper, lead, plastic, wood, rubber, etc. It has a solid fixed structure, a replaceable hammering surface and a bullet-filled structure. Solid fixed hammer is the most widely used. The two striking surfaces of the hammer with replaceable striking surfaces can be disassembled and replaced, and the striking surfaces with various materials and hardness can be replaced, so that the striking range is very large. The loading hammer is filled with steel balls or lead particles, which can eliminate rebound when used, also known as no rebound hammer. The elimination of rebound can significantly reduce the fatigue of the operator. The hammer surface at one end or both ends of the steel hammer has been fully heat-treated and has strong hardness; Generally, the middle section has good elasticity and toughness without heat treatment, which can play a buffering role in the process of hammering and prevent the hammer from bursting. There is a hole in the center of the hammer for installing the handle. ② Handle: There are wooden handle, steel handle and fiberglass plastic handle. The wooden handle is mostly hardwood such as walnut and Sophora japonica, which has good elasticity and toughness, but it is easily affected by climate and has great flexibility, and is gradually replaced by the hammer handle made of the latter two materials.

The use of hammers is extremely common, and there are many forms and specifications. Common ones are round-headed hammer, claw hammer, chopping hammer and assorted hammer (Figure 1). Multifunctional maintenance tool based on hammer. It is a claw hammer head, equipped with a slotted screwdriver, a flat chisel, a triangular file and other accessories, and placed in a hollow steel handle. One end of the handle has a screw for fixing or replacing accessories.