MMM Rock Cutter

[jhgnag]

OK, 10 hours on my new ride & I've done the blades in. I think I should have purchased a rotary cutter either in addition to or instead of my MMM. Our house is just finished on the corner of a farmer's field & it's a little rough.

Anyway, I did my MMM blades in today. Hit a good size rock & the blades need sharpened or replaced at this point. Anybody know what new blades run, or what my dealer might charge me to sharpen them. I'd try it myself, but we're still unpacking at this point.

I can't believe how easily the blades cut up that rock.

 

[hwp]

If you have a bench grinder, unpack it and sharpen the blades. You will hit a lot more objects in due course and have to resharpen the blades many times. You shouldn't need new blades for quite a while. If you don't have a bench grinder, put it on your wish list. In the mean time, try to find someone who has one a borrow the use of it. If you can't do that, take your blades to your local hardware store and they will sharpen them for you. New blades probably cost about $15 each.

 

[Rover]

When you sharpen your blades don't try and get a bid nick out all at once, just live with it for while, its normal.

If you are going to sharpen your blades every 10 hrs you could also use a file, takes a little (alot) longer but does a better job.

I found that a longer bevel stayes sharper longer.

Rover

 

[jhgnag]

Well, went to the dealer today & picked up new blades for $27. Seems awefully cheap to me. This way, I can just keep one set sharp & not have to rush to pull everything off, sharpen, and put it all back together.

I got the MMM off today. Not too bad, but it did take a bit of effort. I can't believe how heavy the thing is. Oh well, nothing wrong with a little exercise.

 

[Hoosier_Daddy]

I use a 4" angle grinder to sharpen my blades. I had some thin floppy disks for the grinder that I really liked that I got from the Farm Show. Used them up and now just use the ones I buy at the local hardware..... I have a friend who has a landscaping/ mowing business and he has a special sharpening machine. Work great but not sure of the cost of it. But, since I don't like using other people's stuff I usually just use my 4" grinder........ Having an extra set of blades on hand is a great plan....... Tom

 

[jhgnag]

Well, I installed the new blades today, but there is still a problem. Every 4-5 seconds, there's a rubbing sound, like the blade is hitting something. Doesn't make much sense to me because if the blade was hitting something, I would think it would happen on every revolution, not every 4-5 seconds. It seems to last about 1/2 a second or so. Any thoughts?

At least I now know how to take the MMM off & reinstall.

 

[Hoosier_Daddy]

A rubbing sound or a vibration?

 

[jhgnag]

I guess I would call it a vibration. It's only when the MMM is engaged and almost sounds like the blade is hitting something...but only every 4 or 5 seconds. The mower seems to be cutting fine, but there is definitely something wrong.

 

[frank_f15]

are u sure that when u cut up that rock u did not damage something else under there?also, u might want to check that all blades are tight and all washers and /or spacers are installed and installed in the proper sequence.be careful, if something is not right it will only get worse FAST, and could be dangerous.

 

[jhgnag]

I'm sure that the blades were put back on right. I took the stuff off & kept the order perfect. Plus, it was happening before I replaced the blades. Any suggestions on other damage to check for?

 

[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