MMM Rock Cutter

[Anonymous Poster]

Did you balance the blades after you sharpened them? You might also take them off and run the mower without them to see if the sound has to do with the the blades or if it has to do with the mower deck itself.

As far as hitting rocks with your mower goes, I have hit more than I can count and have managed to keep from doing any real damage to my mower. And it used to make me crazy when I would mow because it just sounded like I was destroying it.

By the way, when I sharpen my mower blades I always flatten the cutting surface to about 1/16 to 1/8 of an inch. I was told by a mower repairmen that this would keep the blades sharper for a longer period of time. I don't know if it is true or not, but it's how I've always done it.

 

[Anonymous Poster]

Whoops . . I missed the message where you said that you bought new mower blades. Check to see if they are balanced anyway.

 

[TresCrows]

You probably have a bent spindle or the deck is bent in the area the spindle shaft is mounted or there is a damaged bearing allowing slop in the spindle. Also check the belt alignment to the pulleys. Check the blades for tracking--tilt the deck up and rotate them by hand, they should not wobble and you should not see any blades dip or rise. I sure hope it is not a big deal------but--this is one of them I told you so's. The MMM is not a very good rotary cutter and a rock will tear it up and it costs about 4X what a rotary cutter costs. I once worked for a company whose motto was surely---"we will go to any Expense to save a dollar".
Well, maybe it is no big deal, hope not. J

 

[jhgnag]

Thanks for the help. At least I have some stuff to check out today. TresCrows, if it were the spindle, why wouldn't it make a sound with every revolution? Just curious.

Does anyone know how long it takes the belt to cycle. I'm guessing it's more often than every 4-5 seconds.

I agree with you on the rotary mower. Maybe I need one of those too. The only thing is, I won't really need it after I get the yard cleaned up. The rock was a suprise, and I have been through the whole yard many times picking them all up.

 

[DaRube]

I managed to bend a blade on my MMM the VERY FIRST time I took it out to mow the lawn. It made the most awful sound, and I was afraid I'd killed the whole thing!! (A few years back, I had hit a rock with a push mower, which bent the shaft and totalled the mower).

Now I am eyes wide open for rocks in the field, and I have even put flags near them or sprayed them with day-glo paint as a reminder, lol. Perhaps some day I'll dig them out with the FEL and really solve the problem. The worst part is that every year the geological forces push some new ones up......

 

[jhgnag]

Well, two of the blades were barely making contact every 5th-6th revolution. There was a slight wear mark on the edge of both blades. I took a Dremel to the edges just to take a little off & it was fine, but obviously something is bent (ever so slightly).

 

[b8200hst4wd]

You Put the cup washers on wrong that will not allow the blade to make friction to spin the blades causing a vibration sound

i did it once and in did the same thin reversed them and off i went

I have hit so many rocks, don't worry about it

 

[TresCrows]

Yep, I agree with your diagnosis, something is bent--there is no way the blades should ever touch. I don't know if it is the spindle/s or deck or both or something else--the vibration comes and goes--yeah--that is about right, there is a harmonic that develops when the rotating parts get into a certain condition/alignment/etc thus it is not contiuous. Like a siren call it is not so bad and say --use me--it is OK--just a little vibration---till the blade comes flinging off or something. Sounds like your MMM needs the Kubota doctor, I really do hope it works out for you, the worst that can happen is you will need a new 2,000 dollar deck and a 500 dollar rotary cutter--egads, some of us have all the luck. J