Rotary Cutter Rotary Cutter Balance

[AB4D]

I just purchased a new King Kutter rotary cutter. However, the cutter seems to be out of balance, vibrating excessively while in use. The blades swing free, so I assume the blades are probably just out of balance. What is the best way to balance the blades?

Jim

[Bird]

Jim, if it's new, the blades shouldn't be out of balance enough to cause excessive vibration, although I suppose that's possible. I think the first thing I'd do is check to make sure the bolts are in straight and properly tightened. Then I'd try turning the driveshaft by hand to see if there are any "sticky" spots or whether it turns smoothly all the way around. As far as balancing the blades, the only time I did it was when I sharpened blades, and then I simply weighed them on some scales to be sure each blade weighed the same.

[KiotiJohn]

Is it possible that one of the blades was not out all the way when you started? This can happen sometimes if you're not starting with the engine RPM low and then throttle up. If one is out more than the other, the quick start can start the vibration which would continue.

The other thing to check is to make sure the PTO shaft was properly cut for your tractor. There should be about 6" of overlap between the two shaft pieces. If there is too little, it can vibrate a lot, and can be dangerous.

John

[sandman2234]

Balance the blades????
I usually try to even out the chunks of missing metal, but no way are they close enough to be balanced. Too much metal and not traveling fast enough would probably be why mine isn't too rough.
Guess mine should vibrate a lot, but it doesn't.
David from jax

[talldaddy]

Sometimes one of the blades may not be all the way out causing what seems like they are not balanced, which in fact at this point they are not. You can get some spray grease and spray this on top and bottom of the blade pivot bolts and make sure they are swinging freely. Also, keep a check and make sure you don't wind up bailing twine or other string around the bolts. This will cause them to bind up with the blades. In time the bolts and blades will get enough wear on them that they will swing pretty free. If they feel like they are balanced when you start the pto and later while you are cutting they become unbalanced, you can stop the pto and restart with the cutter raised, this should swing the blades back out and it should run smooth.

[OkieG]

Jim,
It's new! Take it back to your KK dealer and let them help you figure it out.

OkieG

[gordon21]

Are the blades the same size? Mistakes do happen at factories. One could be thinner or an inch or two shorter. A pound difference sure would cause some vibration. I am sure the KK factory has half a dozen different blades in their parts bins.

[Farwell]

John,
I agree with you on the pto shaft could be the problem. Mine shook, rattled and rolled but never thought that it could be the pto shaft. I have not checked it yet because I have not needed to use my brush hog this year. I think my problem may be that the shaft is too long for my tractor set up. I have learned from TBN that serious pto issues can be caused by the shaft being too long.
Farwell

[KiotiJohn]

</font><font color="blue" class="small">( I have learned from TBN that serious pto issues can be caused by the shaft being too long. )</font>
That is certain. If it's too long, there would be no room for the shaft to contract (shorten) when the terrain causes the tractor and implement to come closer, and it can also cause the shaft to hit, bind, etc.

There is a constant adjusting of shaft length going on the whole time an operation is going on. Too long or too short are both problematic. I've seen shafts that were too short wobble all over and then come apart. A little too short could be causing the shaft to wobble, but maybe not come apart, probably covered by the PTO shield and unseen.

John

[Wall]

Make sure the yokes on the shaft are lined up correctly