Rotary Cutter rotary cutter...grass clumping...

[ratter]

I was cutting with my new Woods BB72 bush hog the other day. In one area, it's a mixture of grass and weeds that's not very thick, about a foot high. When I was done wiht that area it looked great, almost finished mowed-looking, with the clippings spread nicely. I cut it about 4-5" high. Then another area that is thick grass with little to no weeds, also about a foot high, it just clumped up real bad and looked horrible. Is this a case of not having the rear of the mower high enough? I was having a hard time gauging that because of the way the BB72's deck isn't flat. It kind of peaks in the middle, and slants down to the front and rear and I was thinking the rear might be too low. I figured before I bother changing it, I would ask the TBN'ers if this was a common symptom of having the rear of the deck too low.

Thanks as always...

 

[Birdman253]

It could be due to having the unit "drag its tail."

It could also be due to low rpm. Make sure you run the unit at 540 rpm on the PTO. Your tractor owner's manual will tell you what engine speed that should be, if it is not indicated on the tachometer itself.

If you think it is due to the unit being lower in the back, just shorten the top link some, and try it to see if it improves. Rotary mowers should be run level, but sometimes a little "nose down" will improve the cut. It doesn't take much. If you nose the unit down, you increase the aggressiveness of the blades. Since the top of the deck is sloped, making it difficult to see if it is level, check the bottom of the "side skirt". Almost all mowers will have a portion of the lower edge of the side skirt that is straight, even if they taper up near the rear to allow for material to flow through. Just sight on the straight portion, and adjust till that shows to be level. If the bottom is level, then the rest has to be level too.

 

[Farmwithjunk]

Sometimes that's just the nature of a rough cut mower. Also take into consideration the type of grass/weeds you're mowing. Are they stemmy and tough? I cut a pasture in back of the house where I want it to look like a lawn. I use a Bush Hog to cut it. I've found that cutting with the left side of the mower towards the previous round leaves a better look. Going the opposite direction leaves a windrow along one edge. Oddly enough, the grass I have seems to cut better when slightly wet. (morning dew, or after a light rain) The mower scatters it better and the cut looks cleaner.

Experiment and see what works best.

And yes, the back end of the mower needs to be slightly higher than the front. (I set the back about 1-1/2" higher than the front on a 6' mower)

 

[Marcussen]

I have a new woods BB60 it does not have any openings on the back end for the cut grass to be thrown out of like my old cutter did. I assume this is a safety thing, the mower does have a black removable skirt that is designed to be replaced with a chain guard. I have cut very little with the cutter since I bought it, but I am afraid it would ball up like you are talking about. We are having a draught here so there is no grass growing that needs mowed. When the grass does grow again I will have to decide to remove that guard or not.

 

[ratter]

Thanks for the input guys. I'm going to raise the rear a bit and try more of the same spot and see what happens. It must have a lot to do with the material being cut. A different (rougher, stem-ier) area that I did the same day came out looking almost lawn-like. And to answer the question, always at 540, yes.

 

[3RRL]

Have you read the other thread about PTO rpm? Indteresting stuff.
other thread

 

[Glenn9643]

I use a Bushhog 286 to mow about 13 acres in a field here at the house. I try to cut as close as the bushhog will allow. Normally it's not thick or too high, and I get a good cut running about 2100RPM instead of the 2600RPM to get 540. I also gear up to H2 when running at this RPM. Seems to use half the fuel and time. There's very little clumping of the cut grass.
We have a patch up town with about 2 acres that's heavy bahaia, and by the time I get around to cutting it during the summers it's between knee and waist high. It clumps badly however it's cut. I've found that I do get a better cut at 540RPM on the cutter at a slow ground speed.
Like Farmwithjunk said, what you're cutting can make a big difference.