Tamp

Half minute video of tamping a road surface

A tamp is a device used to compact or flatten an aggregate or other powdered or granular material, typically to make it resistant to further compression or simply to increase density.

• Small, handheld tampers compress ground coffee into a puck in the preparation of espresso.
• Manual or powered tampers compact gravel in the preparation of laying a concrete or brick patio or walkway so that the underlying gravel layer does not settle over time, or compress the fill in a utility trench as seen in the illustration.
• Self-propelled, mechanised ballast tampers, which compact the ballast underneath rail tracks.
• Preparation of some firearms and artillery pieces for firing may involve tamping the charge (explosive material, projectile, and so on) into the barrel.