Newbie question - how to cut tall grass

[jmanx000x]

Sorry about the newbie question, but this is my first acreage and first time trying to cut. I just purchased some land and the grass is 4'-5' tall. I have to get a tractor, but right now I don't know what to get. In the meantine, I am renting an L3830 with 5' bushhog this weekend to cut, but a little unsure how to get started. Any help with the questions will be appreciated.

How to set the height on the bushhog - should the 3pt carry it or should the rear wheel roll on the ground?

How short should I try to cut it?

I think I set the rpm so that the pto rpm is 540? Then how fast do I go when cutting - do I monitor pto rpm to make sure cutter is not bogging down? What about cut quality?

What do I do with all the downed grass? How do I keep it from binding up the cutter?

Anything else I should know about?

Thanks for the help.

Jman

 

[TORQUIN]

I'm no expert, but I'll tell you how I'd do it.
To get the best float, I usually just don't even connect the top link. The rear wheel and the lift arms are what supports the cutter. I run around 480 rpm on the PTO, usually, because it does a fine job at that speed.
Go as fast as you like, as long as the grass is being cut. If you are running 480+ RPM on the PTO you won't bog the cutter much. If you do, just slow down a little. When I cut my grass this way I just leave the grass where it lay. This is standard unless you are trying to make a lawn out of it, but then you'd be going back over with a finishing mower. If the grass is that thick and you still want to gather it, get a rake for the tractor and rake after you cut it.

Now for the cautions. IF the grass is that high, and you do not know whether there are stumps or other junk in the grass, slower is better, and it the tractor has a front end loader, run with it about 4 inches off the ground, so that it will hit the stump first, or push the junk out of the way. I do this if I do not know what's ahead. If you do not have an FEL, or do not want to do it that way, mow in reverse, so that the cutter will hit whatever is out there (hopefully it has a stump jumper, most do) and you won't damage the tractor when you hit something big. The cutter should have a shear pin when the PTO shaft connects to the gear box, so you should not have to worry about hitting a stump and damaging the tractor.


Chris

 

[Volfandt]

The key is to mow at the lowest setting you can without stalling or over loading the tractors engine. At 4' to 5' tall, you'll probably need to go over the same area a minimum of 3 times inorder to get it down and somewhat mulched/chopped up.

I would go at it using the lift only for height adj until I found the "sweet spot" height, then if it's not too high, re-adj the BH's rear wheel to carry the load. If you have to mow the 1st pass too high to use the rear wheel then thats fine. You should be able to on subsequent lower passes.

I doubt you'll stall or overload the BH as long as you don't try to cut it too or go too fast. The main problem you'll encounter will be the long stalks getting wrapped around the PTO shaft. They'll be slinging all kinds of seeds and other debris down your back so wear eye protection and a shirt.

Go very slow on that 1st pass as you won't be able to see any large obstructions laying in that tall grass. Old tires, large branches, paint cans, large rocks, shopping carts etc can wreck havoc on the machinery and you!

540 is the correct RPM and you'll want to stay as close to that PTO RPM as possible. If the BH starts to bog down you either need to raise the BH or slow down your tractors forward speed or both. You'll probably be raising & lowering quite a bit on that 1st pass. After you've got it down it should run pretty constant. Subsequent passes will chop it up pretty good but there will be alot of hay laying around. The more you cut it, the smaller and finer it'll get.
You didn't say how much acreage you'll be cutting but be prepared for alot of seat time. Just take your time, be extremely careful, don't go too fast and keep those RPMs up!
Good luck
Volfandt

 

[btolle]

Read the article Adjusting Rotary Cutters for information on setting up the cutter.


You cannot cut it shorter than 3" with a rotary cutter. As tall as the grass is you may have to make 2 passes but I would try it for a few feet set as low as you want the final cut, you might make it in one pass depending on what type of grass it is. If it bogs down too badly then you will have to set the cutter up as high as it will go and make the first pass then lower it for the second pass.

The rear wheel rides on the ground.

PTO RPM should be 540. Do NOT under any circumstances try to use the 960 RPM PTO setting! In fact, the 960 setting should be blocked out and you would have to loosen a bolt and move a metal blocking piece to get it in 960 but since it is a rental unit it may be possible to put it in 960. Again, DO NOT do it.

Adjust your ground speed so that the RPM's stay up. If you hear the RPM's drop you are going too fast.

If you are not sure what is in the field you might want to be prepared to hit the clutch if you hit a big rock or other foreign object.

Watch the height of the 3 point hitch. Most Kubota 3 PH's will drift downward after a while and you may have to raise it periodically.

To engage the PTO drop the RPM down to 1,200-1,400, push the clutch in, engage the PTO, let the clutch out, then speed up to PTO speed. When you are ready to stop leave the PTO engaged and slow the engine to idle before disengaging the PTO, the engine will slow the PTO and cutter down.

Safety tip: Do not get off the tractor until the cutter has stopped spinning completely. A rotating PTO shaft is extremely dangerous if you get near it.

Do NOT let anyone get near you while operating the cutter. The tip speed on a 5' cutter is about 12,000 feet per minute.That is roughly 135 MPH and sticks, rocks, and everyting else can come out from under the cutter at over 100 MPH. Do not park your vehicle near where you are cutting. The only dent in my wife's 2004 Jeep Liberty was put there by a chunk of wood thrown out from under a rotary cutter we passed by on a highway in Mississippi.

Downed grass: Learn to love it while it lays there turning brown. This is a rough cutter, not a finish mower.

BTW, a rotary cutter blade is not sharp, it has an edge approximately 1/16th" wide. It is make to tear the grass, not shear it.

In case the cutter starts vibrating badly while operating disengae the PTO and let the cutter come to a complete stop and try again. Occasionally, and depending on the brand of cutter, grass will get wedged between the blade and the "stump junper" (big round plate blades are attached to). Once in a while it will clear it self by just stopping and starting over. If it does not clear you will need to stop it, raise the 3 PH to maximum height, SHUT THE ENGINE OFF AND PUT THE KEY IN YOUR POCKET, then put your gloves on and look up under the cutter and wiggle the blades around until you clear the grass out. My old cutter used to get hung up regularly and the easiest way to clear it was with a hose nozzle to blast the grass out from between the blade and the stump jumper.

Hope that answers some of your questions. And, I hope it was not too elementary but I was assuming you had never operated a cutter before so I tried to cover the basics.

Above all, please be safe. Tractors are wonderful and I love my rotary cutter but it can be a dangerous piece of equipment. If in doubt about anything the first rule is stop the PTO, stop the engine, and then think, think, think. Most so called accidents are not accidents at all, they are mistakes made by operators. Even the most experienced operator can suffer from a momentary lapse of memory and get in trouble.

If you feel yourself getting really tired get off the tractor and rest. The work will be there tomorrow. A tired operator is a dangerous operator. When I find myself doing something stupid, or find that I am "fighting" the tractor I know it is time to park it for that day. I have never regretted quitting but I have often regretted continuing when I know I am too tired.

Bill Tolle

 

[BoneheadNW]

Bill-

Thanks for the post. While I do not have a rotary cutter, your safety tips were very helpful. As you said (in different words) , all it takes is a momentary lapse of reason to leave a lifetime of regret.

Bonehead

 

[snakeeater]

All of the replys are great, sound and excellent safety advice..the only thing I would add..is to physically walk the ground to be cut if it is the first time you are cutting it..that way you put your eye on any safety hazards..anyway..it's your new land, right..you might be surprised what you'll find..cars, farm equipment, obstacles,etc..lots of luck..

 

[Doug_Myerscough]

I'll second snakeaters advice on walking the property first - I recently bought an adjoining piece of property that had not been cut in many years. In addition to the thousands of sumacs and other junk trees it had some serious suprises that could have torn my equipment to shreds - old metal bedframes, an engine block half buried, metal fence posts bent over and invisible and tons of other hazards that would have been dangerous flying out of the BH. I had quite a pile of metal before I could even start to mow.

 

[Dargo]

</font><font color="blue" class="small">( might be surprised what you'll find..)</font>

Yup. I had to have a couple of guys walk out ahead of me in really tall grass to find the surprises. I would have hit hundreds of dinosaur eggs (rocks). /forums/images/graemlins/blush.gif Running with a FEL about a foot off the ground will find most things, but not all.

 

[smoothie17]

Also, keep an eye on your temperature gauge while mowing. If your tractor starts to run hot it's usually just a matter of cleaning off the screen in front of your radiator. With grass that tall you'll be surprised at how much "stuff" collects there while mowing.

Enjoy !!!