To choose the best lawn mower blade, begin by determining what size blade the machine requires. After appropriate sizing has been determined, select the blade type that will produce usable grass clippings. Blades may be purchased from any manufacturer of lawn equipment, at local home improvement stores, or from parts suppliers on the Internet.
To determine what size lawn mower blade is required, check the label on the machine. This is typically found on or near the housing for the engine assembly. Most lawn mower manufacturers include the size of the blade in the name of their machine. For example, a label may include the name of the manufacturer followed by phrase like '21 Push Mower.' This indicates that the machine uses a 21 inch (53.3 centimeter) blade and will require the purchaser to push it manually. If the label is hard to find, difficult to read, or in some rare cases does not include the size lawn mower blade needed, simply measure the blade with a tape measure, or other tool, to determine the length manually.
Most manufacturers of this equipment sell replacement blades to fit each type of mower specifically. Consumers may go to a local home improvement store or visit the manufacturer's website directly to obtain a blade made to precisely fit the make and model of their machine. This is not always necessary, however, as most lawn mowers are made in standard sizes and can accept any blade sized correctly for that particular style of mower, regardless of whether the brand name of the machine and the blade match.
Lawn mowers are generally available in one of three styles: push mowers, self-propelled mowers, or riding mowers. Each type generally uses a different lawn mower blade, though some push and self-propelled mowers may be able to use the same design. Blades for these machines may be available for purchase from any manufacturer of lawn equipment.
A push mower is typically electric or gasoline-powered and must be steered and pushed manually. This type usually requires a blade between 20 (50.8 cm) and 22 inches (55.9 cm) wide. Some very small machines may require a blade between 14 (35.6 cm) and 16 inches (40.6 cm).
Self-propelled mowers only require manual steering and are made with blades between 19 (48.3 cm) and 21 inches (53.3 cm). Riding lawn mowers are sold in a much larger variety of sizes and styles than the other two types. Blades for this kind of mower are also between 19 (48.3 cm) and 21 (53.3 cm) inches, though the machine may require more than one blade.
Riding mowers, through two or more blades, can cut a path up to 72 inches (182.9 centimeters) or more. When purchasing this type of blade, ensure that it is labeled for use specifically with a riding lawn mower. These blades typically work in conjunction with one another, as opposed to singly, as is the case with the other mower styles.
A lawn mower blade can be purchased for either standard grass cutting or for mulching. Standard blades are typically flat with two sharpened ends, which cut the grass when the blade is spinning. Grass is gathered in a side or back bag and may be discarded into lawn bags or compost piles. Mulching blades are curved and produce smaller, more finely chopped grass particles. These smaller clumps of grass may be discharged directly onto the lawn rather than bagged, and are more quickly broken down into nutrients.