Cutter shakes like crazy

[Ram4x4]

So, snow is gone and finally got to do some serious hogging on the field. Took the 5035HST out with the 7' HD Mahindra cutter and for the next couple hours it was smooth going. Then, all of a sudden the thing starts shaking like crazy. I didn't hit anything, it just starts shaking. I shut it down, lifted it up and there is nothing tangled in the blades, no missing parts, no broken blades, no bent blades, nothing, perfectly clean, it just shakes like ****.

Any ideas?

[whistlepig]

Could be that the stump jumper has become loose on the shaft.

[Creamer]

Normally this is an out of balance condition. That could be caused by anything that produces more weight on one side than the other. Build up of dirt on a blade, tip broken off that you did not see, blade loose and turned at an angle, etc. I have had one shake if the blade was hitting something on one side as well and it is reacted back to the tractor but i am assuming that even after you lifted it up it still shook which would mean if this is the cause something is stuck inside it - a real oddity.

[Gary Fowler]

I think Whistlepig might be on to something. If the blades are loose and move freely, I would check the nut in the center of the stump jumper. Mine was loose a bit when I checked it. You are going to need a very big socket for that nut and a long cheater pipe to really tighten it up. Don't do like I did and forget to remove the locking pry bar in the PTO yoke that I was using to keep the blades from moving. It makes a heck of a racket and if like me, I ended up with a 180 bend on one piece of the pry bar before it broke the 1" bar. Luckily it didn't damage the PTO shaft though.

[Ram4x4]

Went and took another good look at it. Nothing broken off, no dirt build up on anything, it's very dry weeds/grass, in fact it is very clean underneath the cutter. I disconnected the drive shaft so I could turn the blades and checked from a reference point to see if one blade was passing the point at a different distance. Nope, they are the same. Nut on the stump jumper seems tight, nothing looks out of place. Blades are tight and swing freely.

Not sure what else I can check at this point.

[RickB]

The assumption seems to be that the blades are free to swing on the bolts/pins. Are they? if not, there is the problem.

[AchingBack]

When ever my cutter shakes; I idle down all the way, and disengage the PTO. After a minute, or so, and at idle, I reengage the PTO, and slowly bring the RPM to the proper speed. This has always worked to stop the shaking.

[Ram4x4]

Tried the idle/pto thing, no dice.

Yes, the blades swing freely. Yes, it shakes even when lifted and not cutting anything.

I agree, something is out of balance as that's what it feels like, like one blade is heavier, but nothing is broken off any of the blades, not twisted, etc.

The nut on the stump jumper is a big castle nut and it has a huge cotter pin in it, and it is not broken or twisted.

I'm going to take the blades off and weigh them, heh.

If nothing else, I have a grinder and if they are that much different in weight, I can fix that! Besides I want to sharpen them up some anyway, they were pretty blunt from factory.

Just boggles my mind how all of a sudden they got that way. I'd understand if I had hit something big and solid with it, but I didn't.

My first thought was they might of had some kind of balance weight on them and it came off, but that doesn't make sense. You balance them by grinding the heavy one, even at the factory.

Ah well, kinda puts a damper on the day...and it's supposed to rain tomorrow too, yuch.

[DT86]

Without being there to look it over I can't add to any ideas that have already been mentioned.

Don't sharpen those blades too much. Don't you figure they came blunt from the factory for a reason?

[whistlepig]

The only thing else I can think to check is the mounting bolts for the gearbox.