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Ohio State University Extension


Three-Point Rotary Lawn and Brush Mower Safety

Small Farm and Gardening Safety and Health Series
Agriculture and Natural Resources
S. Dee Jepsen, Associate Professor and State Safety Leader, Agricultural Safety and Health, Food, Agricultural and Biological Engineering
Jeffery Suchy, Graduate Student and Lecturer, Food, Agricultural and Biological Engineering

Rotary lawn and brush cutters are useful compact tractor attachments and are used for reclaiming overgrown brush, pasture maintenance, incorporating cover crops and maintaining lawn areas. Knowing equipment capabilities allows for the use of the right mower for the job. The operator’s manual will help determine if the mower is designed for the intended job.


Three-point rotary lawn and brush mowers have similarities in appearance, but they function differently. Rotary lawn mowers are designed for use in manicured lawn areas that are mostly free from brush and debris, while rotary brush mowers are designed for use in rough terrain containing brush and overgrown vegetation.

Rotary Lawn Mowers

Rotary Brush Mower

These have fixed blades that are rigidly attached to the spindle. The blades are generally thinner and sharper than brush mowers, and are intended for cutting grass to an even height in maintained lawn areas. They are not designed to withstand repeated impacts with hard objects and brush.

Rotary Brush Mowers

These have blades that are not rigidly attached to the spindle but on hinges that allow the blade to pivot if it hits a rock or stump. This helps prevent damage to the equipment and allows the thick, heavy blades to continue rotating to cut through tough brush and vegetation.

Safe Operation

When operating mowing equipment, keep bystanders away from the equipment and have them maintain a clear enough distance to avoid the hazards of being struck by objects thrown from the blades. Never allow riders on the equipment.

Remove all litter and debris from the area to be mowed. Rocks, roadside debris and other objects can be deadly when thrown by a mower blade. 

When using a machine equipped with a rollover protective structure (ROPS), wear a seat belt. Watch for holes and ditches, which may cause loss of mower control. Care must be taken while making turns. A three-point, hitch-mounted mower can swing outward when turning, striking nearby objects and potentially causing the driver to be thrown from the tractor. Adding front ballast weights improves balance and control, and a wide setting for the rear tires enhances tractor stability and reduces the chance of a tractor overturn. Do not operate on steep slopes, and always operate at a safe speed.

Wear close-fitting clothing that won’t get tangled in moving parts, such as the power take-off (PTO) shaft. Basic personal protective equipment (PPE) recommended for mowing activities includes safety glasses, hearing protection, work gloves and leather boots.

Before dismounting from the tractor, disengage the PTO, turn off the engine and set the brakes. The blades will continue to rotate after the power has been shut off. When approaching the mower, make sure the blades are not rotating.

Rotating Blades and Thrown Objects Danger Label Rotating Components
Warning Label

Maintenance and Inspection

Hazard risks increase when equipment is not well maintained. Know proper maintenance procedures. Frequently check machinery for loose parts and blade condition. Mower blades should be replaced if they are bent, cracked or too dull to sharpen. Rotary mowers are equipped with runners and safety guards. To avoid excessive wear on the runners, keep the mower high enough to avoid riding on the runners. Keep all guards in place and well maintained, including the PTO shield. Chain or belt guards cover the space between the bottom of the mower and the ground, and they reduce the possibility of objects being thrown from under the mower. Inspect and replace as necessary due to wear and tear.


• Jepsen, Dee, M. Wonacott, P. Ling, and T. Bean. Rotary Lawn and Brush Mower Safety, AEX-192.1.57. Columbus, OH: Ohio State University Extension, 2006.

Reviewer: Kent McGuire, CFAES Safety and Health Coordinator, Food, Agricultural and Biological Engineering
Originally posted Nov 20, 2015.