What Does a Sickle Bar Mower Do?

How It Works

• The sickle bar mower consists of a long metal bar studded with fixed teeth called blade guards. In use, the sickle bar lies down horizontally. A second, inner movable bar with its own cutting teeth, known as knives, slides back and forth between the fixed blade guards on the outer bar. The fixed and moving teeth shear through standing vegetation with a scissors action. This action works best on grasses and other vegetation that stand up straight without assistance.

Where They're Used

• Sickle bar mowers work best on slopes and grades such as along ditches and lakesides. These mowers also are good in tight areas along fence rows, and they work well for mowing hay on flat fields. A typical sickle bar mower is 5 to 7 feet long and normally is mounted on the side of a tractor. Sickle bar mowers are not suited for areas where grasses are bent over, or where vegetation is unusually dense with thick stalks. Under such conditions, sickle bar mowers are likely to clog between the inner moving parts.

Mowing Technique

• Most sickle bar mowers extend from the right side of the tractor. That means you mow a field in a clockwise squared spiral, working toward the center, then you mow the outside edge going counterclockwise. At corners, you usually have to raise the mower and back up the tractor to take a straight run at the next swath. You can’t do much about small animals that hide in unmowed hay or field grass; they hopefully will move out of the way.

Basic Maintenance

• When sickle bar mowers don’t mow properly, the most likely causes are misalignment between the fixed guards and moving knives, broken or dull knives, or the wrong combination of tractor ground speed and power takeoff speed to the mower. Correct alignment requires the bottom of the knives rest flush on the fixed guards. Guards can be tapped into alignment with a hammer. Dull knives can be sharpened with a handheld grinder. Broken knives must be replaced. Sickle bar blades don’t require lubrication for use; the juices of the vegetation being cut provide adequate lubrication. Before storing your mower for the winter, though, you should coat the sickle bar with motor oil. Damp grass requires a slower tractor speed and faster power takeoff speed than dry grass.