Excavators come in a wide variety of sizes. The smaller ones are called a mini-excavator or compact excavator.One manufacturer's largest model weighs 84,980 kg (187,360 lb) and has a maximum bucket size of 4.5 m³ (5.9yd³). The same manufacturer's smallest mini-excavator weighs 1470 kg (3240 lb), has a maximum bucket size of 0.036 m³ (0.048 yd³) and the width of its tracks can be adjusted to 89 cm (35 inches). Another company makes a mini excavator that will fit through a doorway with tracks that can be adjusted to only 70 cm (28 inches) wide.
To identify the basic pieces, the cab attaches by way of a pin to the deck which holds the final drives which have a gear that drives the tracks. The Boom attaches to the cab by way of a large pin. Attached to the Boom is the Stick. Attached to the stick is the bucket and optionally, the thumb. Usually 2 large hydraulic cylinders lift the boom. Some booms have a swivel capability so the boom can swing independent of the cab. The stick provides the reach along with the boom. Usually a model of excavator has optional lengths of stick that enhance either reach (longer stick) or break-out power (shorter stick). Bucket sizes and configurations are used for varying purposes. A wide "clean-up" bucket is used in situations where too much dig force would make the surfaces uneven. It "cleans-up" a site smoothing and filling the ground. A "dig bucket" is much smaller andusually has teeth to break into the ground. Buckets have numerous shapes and sizes for various applications. "V-shaped" buckets can penetrate frozen ground.
