Rotary Cutter vibration

[DeeDubya]

I've got new Ag Meier Brave cutter and it's got some noticeable unbalance. Being only a 48" I was surprised. I don't think it's enough to hurt anything so I might just wait until I replace the blades. Would it pay to remove the blades and weigh them?

 

[ruffdog]

It could be a difference in blade weight but it could be other things too. If the holes in the disk that holds the blades was not machined correctly, it might be positioning one blade further from the center. Is the center nut tight? Is the blades swinging in the same plane?

 

[oosik]

To my way of thinking a new cutter should have zero unbalance/vibration. Do what you can to locate it and if it still has unbalance call the dealer. One thing for sure, its not going to improve by itself or with time.

 

[Soundguy]

new mower? make sure both blades swung out. paint or rust may have held one in a bit.

 

[hslogger]

A new mower shouldn't do this. Previous poster mentioned that maybe the paint has the one swing arm stuck and that is a real possibility. I just rebuilt an older unit and had it sandblasted and epoxy'd. When I ran it one arm was frozen and I had to get it unstuck.
ANOTHER possibility is that the bolts that hold the gearbox to the deck are loose. Even though they may look tight, it might be that they are loose. I have had that problem in the past and ended up replacing all the bolts because they were thread damaged.

 

[DeeDubya]

Those are all good things to check. I'm sure the blades are swinging as I can easily move them with my hand. But I'll start checking some of the other things as well. The help at the dealer used a fork lift under the deck to load it onto my trailer not even looking where they were placed, so I might have a bent blade or stump jumper.

 

[dal929]

This may sound silly but if check to see if the gear box has gear oil. I have a Brushbull 84 that one weekend just started making a funny vibration. I checked the cutter gear box oil level and it was empty. I filled it back up with gear oil and the vibration went away. It has since leaked out again but this time I filled it with 00 grease.

 

[DeeDubya]

This may sound silly but if check to see if the gear box has gear oil. I have a Brushbull 84 that one weekend just started making a funny vibration. I checked the cutter gear box oil level and it was empty. I filled it back up with gear oil and the vibration went away. It has since leaked out again but this time I filled it with 00 grease.

I bought it in January and haven't hooked it up till now but I didn't see any evidence of a leak when I hooked up. I did watch the dealer fill it when I bought it. Good suggestion though. I'll pull the plug.

 

[RalphVa]

On my LX-4 connected to the 4010, it would often have some imbalance when starting it. I'd often have to restart it a 2nd or 3rd time before the blades would freely swing. If I checked them by hand, they'd almost always swing freely. With the new Frontier cutter on the 1025, this seems to never happen because its hydraulics gradually start the cutter rather than slamming it on like the 4010 did.

So, if your tractor slams the cutter in gear rather than gently starting it, the blades can somehow get out of proper swing.

Ralph

 

[dal929]

I bought it in January and haven't hooked it up till now but I didn't see any evidence of a leak when I hooked up. I did watch the dealer fill it when I bought it. Good suggestion though. I'll pull the plug.

The first time I didn't see it leak out as it was always over grass. The second time I left it on dirt road and there was a large puddle of gear oil.

 

[Dan Hunter]

On my LX-4 connected to the 4010, it would often have some imbalance when starting it. I'd often have to restart it a 2nd or 3rd time before the blades would freely swing. If I checked them by hand, they'd almost always swing freely. With the new Frontier cutter on the 1025, this seems to never happen because its hydraulics gradually start the cutter rather than slamming it on like the 4010 did.

So, if your tractor slams the cutter in gear rather than gently starting it, the blades can somehow get out of proper swing.

Ralph

I've had this happen on my MX-5 a couple times. Engaging and disengaging until it quit shaking cured it.

 

[DeeDubya]

On my LX-4 connected to the 4010, it would often have some imbalance when starting it. I'd often have to restart it a 2nd or 3rd time before the blades would freely swing. If I checked them by hand, they'd almost always swing freely. With the new Frontier cutter on the 1025, this seems to never happen because its hydraulics gradually start the cutter rather than slamming it on like the 4010 did.

So, if your tractor slams the cutter in gear rather than gently starting it, the blades can somehow get out of proper swing.

Ralph

No I wouldn't say it slams it on, but you can feel the torque when it engages. I think the blades are extending. I can't imagine cutting for several hours without them ever straightening out. Also, I think if one was folded back the vibration would be much worse than it is. I'm going to check for a bent pan next time I'm there. I'm still betting the guys at the dealer bent something with the forks when loading.

 

[foreman Etexas]

I have run into mine doing it,when running at wrong rpm. Can throttle it and get it lined out.

 

[Mike_Kanzer]

One more thing to check is that all the bolts on the framework extending back to the 3 point hitch are tight. On my Woods 5 ft cutter it will vibrate if there is a loose bolt on one of the bars suspending it from the 3 point hitch. Mike

 

[Soundguy]

No I wouldn't say it slams it on, but you can feel the torque when it engages. I think the blades are extending. I can't imagine cutting for several hours without them ever straightening out. Also, I think if one was folded back the vibration would be much worse than it is. I'm going to check for a bent pan next time I'm there. I'm still betting the guys at the dealer bent something with the forks when loading.

could be bent when lifting as you surmise.


prop the mower up, disconect pto shaft and spin her by hand using a big screwdriver thru the yoke and then watch it spin underneath.. do crib it well and don't get right under the mower!!!

 

[DeeDubya]

I was thinking about locking the brake, raising the deck, throttle to idle, switch it on, and walk around back to watch it turn. Or, might it be moving too fast to see well?

 

[Soundguy]

maybee.. be carefull around a running mower if you are on the ground.

 

[RalphVa]

Dangerous. Don't do it. I'd squirt some silicone onto the bolts holding the blades in place and around the top of the blades up under the stump jumper. Could be something is binding up.

Swing the blades a near 180 degrees and see if you can detect any binding at any place.

Last thing would be to remove the blades and check whether they're the same weight.

Ralph

 

[Soundguy]

they'd have to be signifactly different to cause a vibration on a rotary cutter.