Rotary cutter and bad vibration

[livemusic]

I have a Woods Heritage HC72 rotary cutter on Mahindra 5010 tractor. Have been clearing saplings and when I hit something stout that is a bit of a challenge for the cutter, a sapling stump or a 2" to 3" stem, sometimes the cutter will come out of that 'event' vibrating badly and it seems like I have to 'do something' to end the heavy vibration of the entire cutter. So, I reduce power or even shut it off and go again.

My cutter is rated for 1" saplings, which surprised me when I read it in the manual, that it is 'only' 1" rating, but others on here have said that is ridiculous, that the cutter will handle pretty much anything the tractor will push over. These days, I am not willing to use it in that manner, I am not 'mulching' saplings with my cutter, I am just pushing them over and raising up my cutter so it doesn't mulch. But sometimes I hit something. Just wondering if this is normal for the severe vibration to occur after hitting something stout.

 

[fidowanttobe]

That happens to me also. I believe it is "the wrap" of that doesn't let a blade swing back totally. Sometimes I have to clutch and lift quick to clear it.
I know! Sometimes shakes the tractor too.

 

[ArlyA]

If your cutter is rated for just 1" saplings, you best be very carefull with it or you'll be looking for a heaver duty cutter. (or parts)

 

[deserteagle71]

I have found that most vibration in my rotary cutter is caused by the blades not able to swing freely on their pivot points. So when one of the blades hit something that causes it to deflect back, away from a straight line from the opposing blade, it doesn't pivot back straight because it is sticking. Every so many hours now I get under the mower and make sure the blades pivot freely; wish there was a grease fitting on those pivot points.

 

[ericm979]

What do you do to make the blades pivot freely?

The blades on my cutter appear to pivot freely when I move them by hand but sometimes when I engage the PTO (with engine at idle) they get in a phase where when I rev up the tractor there is a lot of vibration from the mower. I have to disengage the PTO, let everything come to a stop and try again. Sometimes a few times. Eventually they'll get set to where there's little vibration.

This didn't used to happen until the mower body pulled a big rock out of the ground and the blades beat on it for a while. It turned out that the slip clutch was too tight from the factory. My mistake for not checking it.

 

[3gunr]

Mine will get grass or bark trapped above the blade and pan and has to be cleared , sometimes i just spray some pb blaster up there and work the blade around , stops the shaking.

 

[TCP2020]

Have you checked to see if a chunk of one of the blades is missing? I was using a 7 ft Brown mower a few months ago and hit something hard as you describe. It broke the blade in two (old blade needed replacing anyway) and it made a horrendous noise until I shut it down.

 

[deserteagle71]

Mine will get grass or bark trapped above the blade and pan and has to be cleared , sometimes i just spray some pb blaster up there and work the blade around , stops the shaking.

^This is what happens with mine. After several hours of mowing (and I mow desert, not grassy fields) debris gets caught between the blade and the pan to where the blade is very difficult to move. I have to spray PB Blaster or WD40 while working the blade back and forth, which causes all that debris to clear out of the pivot point, until the blade rotates freely again.

So if your blades rotate freely while at rest you have a different problem. Blades on my mower have a rough life. Changed mine last fall...here's old versus new:

 

[livemusic]

Have you checked to see if a chunk of one of the blades is missing? I was using a 7 ft Brown mower a few months ago and hit something hard as you describe. It broke the blade in two (old blade needed replacing anyway) and it made a horrendous noise until I shut it down.

Yes, good point, but I checked and the blades looked normal and I also do not see anything trapped above them. Thinking that what happens with me might not be that abnormal... big blow... blades get out of sync... need to stop and start over to get them going again. And it might be the blades are a tad out of balance. (But the blades do look to be in good shape.) I bought this rig used and it's several years old. Maybe even 8 years old. The seller told me it is 2017 vintage but I called Mahindra and they said it is older, I think, 2014. The cutter also endured some abuse because it has some significant dents on the underside of the deck. The tractor also has a 'significant' dent to the front grill. So, maybe the owner was a tad hard on equipment. He has tons of equipment, like a jack of all trades horse trader type of guy. I hope that doesn't haunt me, lol. I trusted him. Uh-oh.

 

[jeff9366]

Lay off the seller.

You are the one abusing a 1" rated cutter for cutting 2" - 3" material.

Take responsibility.