How to Use a Rough Cut Mower

For those who live in an agricultural or rural area where wide open spaces abound, keeping the weeds, brush, and high-growing grasses under control can become too large of a task for an ordinary mower. Many who live in this type area will eventually invest in a small farm tractor and rotary mower (also known as a brush hog or "Bush Hog" - actually a brand name). There is also a type of rough mower called a "flail mower". This type uses many very short blades on a horizontal drum. Strongly consider a flail mower if there are rocks or you may encounter debris. The short knives avoid throwing projectiles, which when thrown from a rotary mower could injure those within a great distance. Add to your understanding of safe and efficient operation by moving down to Step 1.


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    Make sure your tractor is in good operating condition. Since rough mowing may require going into brushy or bushy areas, you may want to modify the tractor to protect the front end components, such as the steering linkages and radiator screen to protect these from limbs or other hazards.
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    Use a mower that is the correct size and configuration for your tractor. The manufacturers of rough cut mowers build and rate them according to two criteria:
    • Gearbox horsepower (torque). A 50 horsepower tractor will likely damage a 25 horsepower mower gearbox under heavy load, and a 30 horsepower tractor cannot operate a large mower equipped with a 90 horsepower gearbox. A good fit is no more than 10% difference in tractor/mower horsepower rating.
    • Cutting width. Smaller tractors, obviously, will handle only smaller sized mowers. For a typical 25 horsepower tractor, a 5 foot (1.5 m) mower is recommended, where a 40 horsepower tractor should be able to handle a 6 foot (1.8 m) mower, and larger tractors can handle proportionally larger mowers.
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    Adjust the sway chains/implement stabilizers so the mower cannot swing too far when turning corners. A mower deck can swing far enough, in certain cornering situations, to hit the rear tires of the tractor, possibly ruining it. If using a flex-wing cutter, be sure to adjust the safety chains on the draw bar so there is enough slack for turning.
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    Check the condition of your mower. Keeping the mower in good condition will decrease the chance of a breakdown while you are mowing. Some things that may need attention:
    • Gearbox lubrication. Typical gear boxes have two pipe thread type plugs built into the housing. One, at the top, is the fill hole, another, on the side, is the fill level. Check oil level in the gear box and if needed remove both plugs, and pour oil in the upper hole until it begins to trickle out the lower one, then replace both plugs.
    • Ground wheel condition. The ground wheel supports the rear of the mower to keep it from digging into the dirt if the mower is operated in unlevel conditions. It should swivel easily so the mower follows when the tractor turns, and the wheel should turn freely on its axle. Lubricate the grease fittings on this assembly, and make sure no debris is tangled around the wheel hub or axle. Also check your tail wheel chains (if your cutter has them) to be sure they are in good condition.
    • Power take-off connector or "PTO". Usually, this is a splined connection with a pin or spring-loaded locking mechanism to hold it in place. There are several sizes of PTO shafts; if you have the correct tractor/mower combination, you will be able to slide the mower drive shaft onto the tractor PTO shaft without trouble. Lubricating the splines on this assembly makes it easier to make the connection when changing out equipment.
    • Universal joints. These are similar to the U-joints on a car or truck, and allow the drive shaft to travel without bending while it is rotating. Make sure the universal joints are tight and grease them if they have grease fittings. Also make sure the PTO shaft guards are in place and safety chains are attached to both the tractor and the implement when operating. This will prevent vegetation from getting wrapped around them while cutting in dense areas.
    • Top-link connection. The top link on a rough cut mower is not a fixed length, as are most other farm implements. This is because the ground wheel raises and lowers the rear of the mower to follow the ground contour, and the top link would bind if it were a fixed length. Make sure the top link adapter on your mower allows several inches of free travel, while still allowing the mower to be lifted clear of the ground while turning. If, while cutting, you notice the mower still has to much "free travel" take up more slack on the top link.
    • Mower blades. A 5 foot (1.5 m) rough cut mower is usually equipped with two 24 inch (61.0 cm) blades, attached to the blade mounting plate under the mower deck. These should be balanced and sharp for good, clean, and vibration free service. If blades are worn bad on the edges it is best to just replace them with a new set instead of trying to sharpen a badly worn set and getting them balanced.
    • The blade mounting plate. Make sure the bolts or studs that attach the blades are tight. This should also be equipped with a stump jumper, to lift the bottom of the gearbox/blade assembly clear of stumps or other obstacles.
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    With the tractor "Off", Hook up your mower and connect the PTO shaft. Make sure the shaft locking mechanism engages, to prevent the shaft from vibrating loose while operating. Check any shaft guards to be sure they are in safe operating condition.
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    Crank your tractor, engage the clutch fully (tractors usually have two stage clutches, so the clutch must be fully depressed to disengage the PTO), and engage your PTO. Make sure your engine is not at idle because it will load the engine to much if you engage the PTO. A little above low idle is best because it will not load the engine as bad. Let out the clutch slowly until you feel the PTO start to engage. The blades on the mower are hinged so you want to engage them slowly until centrifugal force slings them out then you can go ahead and bring your engine up to operating speed. The mower blades should begin turning. If there is any problem, disengage the PTO immediately.
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    Use the three point hitch hydraulics to raise the mower to the desired cutting height, and select a gear appropriate for the cutting job you are doing. For light weeds/grass, you may choose to operate in a gear that gives a ground speed of about 7 mph (11 km/h). In the tractor in the photos, this would be 6th gear. For heavy weeds, brush, or mowing crops after they are finished, a 4 mph (6.4 km/h) speed may give better results, so 5th gear may be used. Also your power to your PTO will change with different gears so be mindful of that when choosing a gear.
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    Begin mowing. Keep the wheel aligned with the direction you want to travel. This may seem obvious, but in a large field with no rows or other features to guide a tractor operator, the machine may drift. It sometimes helps if you are operating in a large field to pick a reference point across the field and keep the tractor lined up with whatever it may be.
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    Select your mowing route in the field or area you are mowing, and follow it either in return row or circular configuration, which ever is more efficient. A circular mowing path is usually more efficient.
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    Listen to the tractor engine, and observe the exhaust, if your tractor has a diesel engine. Black smoke or a reduction of engine speed may mean you are overloading the engine. You should not exceed the limits of your tractor when mowing, doing so can cause premature failure of drive train components. If the tractor is lagging, losing power, or otherwise struggling with its load, either reduce the mower cut by raising the mower, raise the RPM of the engine if you are not already operating at full power, or drop to a lower gear to reduce the tractor speed. A reduction in tractor speed will not only give the tractor more time to cut it will also provide more power to the PTO.
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    Watch for obstacles in the vegetation you are mowing. Stumps, holes, or large rocks can ruin a mower, and hitting a large hole with a tractor wheel can cause the driver to be thrown from the machine. Each pass gives you an opportunity to look at the next cutting path as you pass. If you do happen to hit a rock or a stump always shut down to check for damage before continuing—even if everything seems to be OK. Little problems can turn into big issues quick.
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    Keep an eye on the gauges. Watch carefully, the engine temperature, oil pressure, and fuel gauges to ensure these stay in appropriate ranges. Mowing large vegetation can put a considerable strain on a tractor cooling system, and debris falling from the vegetation can obstruct the radiator screen. If the tractor starts running hot, more than likely, the radiator fins are clogged with debris. The best way to remedy this situation is to use an air blower (if possible) and blow in the opposite direction of the air flow of the radiator fan to clean out the fins.
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    Keep the mower deck ground rails from plowing, or digging into the earth. Even when properly adjusted for level ground, occasionally, a skid plate will dig into the soil when crossing a small contour, and earth and vegetation can accumulate at the corner of the mower deck. These accumulations can quickly become huge masses and soon cause cutting problems. Glancing back at the mower deck frequently will allow you to monitor and maintain the deck height and adjust the height when needed.
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    Use care if mowing under tree limbs or other overhead hazards. Not only can these obstructions break off a muffler or bend the sheet metal of your tractor, you can actually be swept off the machine. Slow down when approaching any obstacle, and be prepared to stop.
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    Understand the limits of what your mower can cut effectively. Because people refer to rough cut mowers as Brush Hogs, they often assume the mower is capable of cutting bushes. To some extent, this is true, but if you are inexperienced or doubt the tractor/mower's ability to handle large, thick bushes, avoid them. Also, when cutting thick brush, the mower is more likely to throw dangerous debris. Always be aware of what is around you if you do decide to tackle some thick brush.
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    Keep an eye out for insects. When mowing under trees, it is common to find yourself wrapped up in spider webs, and not too unusual to find a spider stuck on your hat or glasses. Ground bees (yellow jackets), wasps, and hornets are other hazards, and tractors are not the fastest escape vehicles for avoiding these painful pests when you encounter them. In the extreme event you have to leave your tractor suddenly to avoid these pests, make sure you pause long enough to pull the kill switch or at least take it out of gear. DO NOT LEAVE THE OPERATOR SEAT WHILE PTO IS IN GEAR.
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    Enjoy your mowing job. Nothing beats the smell of fresh mowed grass under a clear blue sky. Remember, some jobs are hustle and bustle, but that is not the tradition of agricultural life. Take your time and at the end of the day be proud of all you have accomplished.


  • Don't try to mow a field early in the morning or after a rain. The added moisture will cause the exhaust to clump, resulting in slow going and a poor job.
  • Avoid scalping while mowing. If your mower blades hit the dirt, they are likely to become dull quickly.
  • Mowing with the tractor wheels at their narrowest setting will allow you to mow much closer to obstacles.
  • For irregular shaped lots, you will find it more efficient to first mow the border of the area. Once you have circled the entire area with the mower, square up your work by fixing your vision on a distant object that you can mow towards. Then go back over the irregular shape you have created, making sure to mow all of the irregular area before you proceed to mow the large rectangle you have defined. As you mow the large rectangle, be sure that the mower deck discharges to the outside of your work (the over-mown area). Otherwise, each pass will find the tractor and mower working harder and harder as you keep mulching the cuttings.
  • Keep your mower blades sharp. Sharp blades wear much more slowly than dull ones.
  • Mow only at a speed you are comfortable with. Many tractors have no operator restraint devices or roll-over protection.
  • If you are mowing to reduce small-fuel fire hazard, rather than for lawn-like appearance, make sure to mow when it is cool and damp. This reduces the chance of fire from sparks caused when the blades hit rocks. Some jurisdictions prohibit mowing after noon.


  • There are times to use an iPod and times not to. Mowing with a tractor is not one of the times, even with the expensive noise canceling ear phones. In order to hear your music, you'll have to turn the volume up so loud you will damage your ears and you will not notice the damage to your hearing until it is too late.
  • Check the fuel and be sure you have enough to complete the job. Running out of fuel may require you to go through the painful, time-consuming priming process.
  • Wear a bandanna or some sort of protection for your nose and lungs. A simple bandanna around your neck can be effective. When your mowing kicks up dust, pull up the bandanna to cover your nose and mouth just like Rowdy Yates did on Rawhide.
  • Be especially careful of obstacles when backing the tractor with the mower attached.
  • Wear the proper clothing. A long sleeve shirt, jeans, and a cap can protect you from critters you disturb mowing, like ground wasps. Their stingers won't penetrate jeans, caps or thick cotton shirts, so if you do get attacked, you can avoid most of the stings. And, don't jump off the tractor if you do get stung, it won't help things. If you are sensitive to stings, keep a bottle of Benadryl or other over-the-counter antihistamine in your toolbox. It might save your life. Furthermore, a good pair of sunglasses will protect the health of your eyes; you may want to ask for the kind of sunglasses that have a dual-purpose function as safety glasses, they will come in handy for many outdoor projects.
  • Don't mow with your cell phone in a case clipped to your belt. The movements you make and the constant bumping and jostling can dislodge your phone. So, leave your phone in the house or at least put in in your pocket.
  • Observe all warnings posted on the mower.
  • Avoid drop-offs, embankments, or other obstacles when mowing.
  • Never operate a tractor or other equipment if you are not in good condition, alert, and well-rested. Fatigue or the influence of medications, alcohol, or drugs may reduce your ability to operate the equipment safely.
  • Understand that a rough cut mower can discharge debris at a high speed anywhere around the mower deck. A stone or limb can quickly become a dangerous projectile.

Things You'll Need

  • Tractor
  • Mower
  • Personal protective equipment, including gloves and safety glasses

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