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Discussion Starter #1
So with only 5 hours on my new X350, I hit a stump and bent the deck. The mower shut off immediately, but when I fired it back up and turned on the mower deck I heard metal crashing together. I shut it down and took the deck off and saw that the blades were hitting and figured I bent one. I replaced the blades and they were still hitting. Then noticed the blade on the discharge side was out of level by almost a 1/4" and the paint was cracked on top of the deck by the spindle. I pulled the spindle and did some banging and prying and got it back to where it should be. Im a little surprised at how easily it bent. I have the accel 42 deep deck. I thought this was supposed to be a heavier duty deck? Has anyone else had this experience?
 

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2 ounces at 18,000 FPS (blade tip speed) gives almost 600,000 ft lbs of energy. That will take out a heavy duty deck too.
That FPS seems a bit high for a X300. A X300-series with a 42-inch deck has a blade rotation speed of around 2900 RPM.
 

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In the last 15 years or so, I can't even think how many stumps I've hit with the 48 Edge deck on my Z445, and before that the 48C deck on my LX277AWS. My decks have really taken a beating. I don't know if they're making them differently these day but mine work as well as the day I brought them home.
 

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Discussion Starter #5
regardless of rpm's, it did damage. When I put the new blades on, they were actually overlapping by almost an 1/8". It was at that point that I knew I had a problem. I hit all kids of things with my old craftsman and never had a problem like this. I guess 20+ years ago they used better steel. I'll be more careful going forward.
 

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Take micrometer and measure your current deck to the old deck if you still have it. You will find it thinner. Plus I don't think they use the same mix of steel and heat treating like they did a few decades ago.
 

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That FPS seems a bit high for a X300. A X300-series with a 42-inch deck has a blade rotation speed of around 2900 RPM.
And the rotational weight was kept minimal to illustrate the idea. I think residential mowers are about 3000fps slower then commercial but I don’t know which is 18k. Then there is the variable of stopping distance, and where the impact was on the blade.

I don’t intend to be confrontational, I just want to show it was a conservative guesstimate if the force involved.
 

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2 ounces at 18,000 FPS (blade tip speed) gives almost 600,000 ft lbs of energy. That will take out a heavy duty deck too.
Think ya need to divide by 60 again to give FPS.

205 MPH blade tip speed = 1082400 Feet per hour /60 = 18040 feet per minute /60 = 300.66 feet per second.

Did this when a little 1.92 ounce piece of oak stick (stick approx. 1" diameter and 6" long, approx. 1.92 oz.) blasted thru plastic deflector shield on my Z Trak.

Figured out the stick hit with 168.55 foot pounds of energy using ballistic formula.

Lots more Kinetic energy wrapped up in a powered up mower blade than a free flying little stick me thinks.:dunno:
 

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Think ya need to divide by 60 again to give FPS.

205 MPH blade tip speed = 1082400 Feet per hour /60 = 18040 feet per minute /60 = 300.66 feet per second.

Did this when a little 1.92 ounce piece of oak stick (stick approx. 1" diameter and 6" long, approx. 1.92 oz.) blasted thru plastic deflector shield on my Z Trak.

Figured out the stick hit with 168.55 foot pounds of energy using ballistic formula.

Lots more Kinetic energy wrapped up in a powered up mower blade than a free flying little stick me thinks.:dunno:
Your correct on the failed conversion. It still comes out to a rifle shot of energy with decent rotational weight, then you add the other blades and shafts connected to in the system and it’s capable of damaging any deck made.
 

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I just accepted delivery on an X739, and spent a number of weeks prepping the lawn in anticipation of it's arrival, as well as a BUNCH of tree removal and service work. My hands are still sore from ax-ing and using a large sawzall to get rid of all of the roots and stumps on the property, filling multiple large trash containers full of stump pieces and roots in the process. I filled a number of holes with new topsoil as well (the lawn in total got 28 tons in a larger scale landscaping/remodeling project) as the spots where the stumps were removed left some sizeable holes and low spots, so I wanted to smooth those out as well. I burnt up a whole six pack of those Milwaukee "The AX" footlong blades in the process in cutting out what the stump grinder from the tree service missed, prepping the lawn, driveway boundaries, and new flower beds for their new, treeless role. I am very impressed with the Milwaukee "Super Sawzall" as well, putting it through what would be an "ultimate test" in any case. I was cutting through 9+" root sections then busting them out of the ground with a large spade shovel.....did I tell ya how much my hands still are sore, LOL....

I mowed all involved areas with a push mower set on a low setting before I would allow the new tractor to see it. Having put a crankshaft through an engine casing last season I wanted to make sure I didn't have a rerun. I feel pretty confident that I got them all, but not without a BUNCH of hard work and persistence in the process.

It's a really good idea to make sure that a new owner of one of these machines does a thorough survey of their lawn before letting said new machine see the lawn. I anticipated needing to do this from prior issues in stump removal and prior mower damage and made sure the new Deere wasn't a victim to any "leftovers". It's really interesting to me seeing this thread come up, given what I've been doing to my property in recent weeks. Sorry to hear that you have to go through that, but it doers serve as a warning to new owners to make sure that ALL obstacles are dealt with before putting such a machine into service.
 

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Your correct on the failed conversion. It still comes out to a rifle shot of energy with decent rotational weight, then you add the other blades and shafts connected to in the system and it’s capable of damaging any deck made.
Couldn't believe a little stick went thru the Deere deflector shield until I did the calculations.

The shield is deceptively thin, plus a design flaw where they put one corrugation (probably for strengthen) right
along the main discharge path.

Figure the stick (1 " diameter hit the corrugation perpendicular) and that put all the 168 Ft. lbs. in that 1" area and it went right
thru that approx. 1/8" thick plastic and flew about 30 feet afterward. :banghead:
 

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Sometimes it’s just bad luck. I have hit a thousand rocks that my X580 has never flinched at. One fall the leaves were everywhere. I was in a hurry. I literally ran thru some leaves and set the deck down on a massive rock that brought the tractor to a stop. I almost cried because I knew the deck had to be destroyed. Fired it up and it ran fine. My neighbor ran over a 3 inch rock and bent his deck. Sometimes you hit things just right. It’s mostly just bad luck.
 

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I have some spruce roots in my lower field/swamp that I have been mowing over and around for years. Even still if I approach from a new angle I am sometimes surprised at the trouble I can get into.
 

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Discussion Starter #14
well I got the deck straightened out and everything back to normal. Then I checked the deck for Level and it was wayyy off. I only have 5 hours on the machine so My guess is that was never level from the day I picked it up from the dealer. It was low by almost 3/4". My guess is that is why I hit that stump in the first place. Should I contact my dealer and complain? I know its not easy to prove or should I just move on and be greatful it wasn't something worse?
 

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well I got the deck straightened out and everything back to normal. Then I checked the deck for Level and it was wayyy off. I only have 5 hours on the machine so My guess is that was never level from the day I picked it up from the dealer. It was low by almost 3/4". My guess is that is why I hit that stump in the first place. Should I contact my dealer and complain? I know its not easy to prove or should I just move on and be greatful it wasn't something worse?

Call the dealer to complain that you hit the stump because the deck wasn't level or cutting lower than marked? Do you really have your lawn cutting around the offending stump that precisely measured out that 3/4" will make a difference?

I'd suggest that you move on, I can't imagine winning or any upside to that argument.
 

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well I got the deck straightened out and everything back to normal. Then I checked the deck for Level and it was wayyy off. I only have 5 hours on the machine so My guess is that was never level from the day I picked it up from the dealer. It was low by almost 3/4". My guess is that is why I hit that stump in the first place. Should I contact my dealer and complain? I know its not easy to prove or should I just move on and be greatful it wasn't something worse?
It might be worth bringing up, but with the realization that they are not likely to do anything about it.
If you KNOW that mowing 3/4" higher wouldnt have hurt the deck, and you had planned that accordingly, then its possible thats the issue and they MIGHT listen and do something.
Having seen most of the lower end decks, they are just that, and they all seem to be about identical in construction and thickness regardless of brand. They are just fine for residential stuff, but are most certainly not heavy duty by any means. If you want heavier duty, get a 7 Iron or welded deck.

I personally dont mow over stumps when I can help it. I make sure if there are any, they are level with the surrounding ground or I dig them up. If they arent, I dont take a chance. You never know what could be up with your mower. A low tire can cause the deck to be off that much, and you might not have caught it before you find the stump, or whatever obstacle is hiding.
I wont even mow close to Maple trees because their roots tend to "knuckle up" and cause the same type of issues.
 

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well I got the deck straightened out and everything back to normal. Then I checked the deck for Level and it was wayyy off. I only have 5 hours on the machine so My guess is that was never level from the day I picked it up from the dealer. It was low by almost 3/4". My guess is that is why I hit that stump in the first place. Should I contact my dealer and complain? I know its not easy to prove or should I just move on and be greatful it wasn't something worse?
The dealer would probably suggest that you obtain a sand hammer and commence to pounding.
 

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Hi, I agree with the others here in that I don't think that your dealer is going to do anything in regards to fixing anything resulting from your encounter with the stump but that deck should not have been delivered to you without being set up properly. On the other hand, you don't know till you try. At the very least the dealer should set up the deck properly. You paid him to do it already and it wasn't done.
 

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well I got the deck straightened out and everything back to normal. Then I checked the deck for Level and it was wayyy off. I only have 5 hours on the machine so My guess is that was never level from the day I picked it up from the dealer. It was low by almost 3/4". My guess is that is why I hit that stump in the first place. Should I contact my dealer and complain? I know its not easy to prove or should I just move on and be greatful it wasn't something worse?
Have you considered that hitting the stump and the subsequent metal mashing with the blades that took place because of the bent deck and all of your back and forth to fix it caused it to be out of level and that they had it set correctly at first? Not blaming you, just playing Devils Advocate here-who knows how much effect all of that trauma caused ...
 

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Discussion Starter #20
I just sent my dealer an email, I'll let you know how it goes. I don't think the deck came out of level that far from the impact or taking it off and reattaching it. But it was not level side to side or front to back and I believe that's what caused the impact. Its only a little 12" round stump and was cut down to the ground. I has since been cut even lower than that.
 
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