A hammer is a handheld striking tool used to drive fasteners, shape materials, or deliver impact. In its simplest form it consists of a weighted head mounted on a handle. Hammers are among the oldest human tools and appear in many forms tailored to particular tasks — from woodworking to metalworking and demolition. Commonly the tool is used to force nails into materials such as wood or to provide controlled blows during construction and repair.

Structure and parts

Most modern hammers share a few basic parts: the head, the face, the peen or opposite end, and the handle. Materials and shapes vary to suit function. Typical components include:

  • Head: the heavy portion that delivers the blow; usually forged or cast steel.
  • Face: the flat striking surface that contacts the work.
  • Claw or peen: the rear part of the head; in a claw hammer it is curved for pulling nails, while in a ball-peen hammer it is rounded for shaping metal.
  • Handle: provides reach and control; commonly made from wood, fiberglass, or metal with a grip.

History and development

Hammers evolved from simple stones used as percussive tools in prehistory to specialized metal-headed tools after humans learned to shape and fix metal to handles. As metallurgy, woodworking and construction practices advanced, the hammer diversified into forms optimized for prying, finishing, forging and heavy impact. Industrialization and improved materials led to stronger, lighter designs and a wider array of specialized heads and handles.

Common types and uses

  • Claw hammer: general carpentry and household work; one side for striking, the curved claw for extracting nails.
  • Sledgehammer: heavy head and longer handle for two-handed swings used in demolition and driving large stakes.
  • Ball-peen hammer: metalworking and riveting; a flat face and rounded peen for shaping and peening metal.
  • Mallet: usually made of wood, rubber or plastic; used when a softer blow is needed to avoid damaging the workpiece.

Choices among these depend on the task: a framing hammer favors weight and balance for driving many fasteners, while a finishing hammer emphasizes a smooth face to avoid marring surfaces.

Care, safety and notable distinctions

Proper selection and maintenance extend a hammer’s usefulness. Inspect handles for cracks, keep heads securely mounted, and replace worn or mushroomed striking faces. When using a hammer wear eye protection, strike squarely to avoid glancing blows, and use the correct type for the job to reduce risk of injury. Distinguishing among hammer types — by head shape, weight and handle length — helps match tool to technique and material. For additional general information see a basic tool guide or introductory reference (tool guide).

Whether in ancient crafts or modern construction, the hammer remains a fundamental, versatile hand tool. For quick references on nails, materials and woodworking techniques consult practical manuals and how-to resources (nail guide, woodworking basics).