Grass Trimmer Parts

• Grass trimmers use a gas or electric engine to spin a head holding a string. The centrifugal force generated by the spinning head causes the string to extend away from the hub. The string serves as the cutting agent to trim the grass. While the actual components of the grass trimmer vary with the manufacturer, the major parts of the machine are consistent across brands.

Engine

• The engine of the grass trimmer provides the power necessary to trim grass. Gas engines are common in the more powerful units and are often two-cycle, one-cylinder engines. These engines burn a mix of gasoline and special oil. Electric powered grass trimmers use either batteries or are connected to an outlet by an extension cord. Battery trimmers are limited in power and run time by the capacity of the battery. Gas engines are generally mounted on a shaft held above the ground by the operator while electric engines are often incorporated into the head of the trimmer.

Shaft

• The shaft either separates the gas engine and operator controls from the head or separates the operator controls from the engine and head in the case of an electric trimmer. In either case, a shaft should be long enough for comfortable operations with enough space between the operator handles and controls and the head.

Trim Head

• The trim head is the business end of the grass trimmer; a user holds this part close to the ground during operation. The trim head houses the drive assembly and the string mechanism. Features to consider include the bump feed string feed, which extends the string if the bottom of the trim head assembly bumps against the ground, and the ease of installation of the string spool.