X-Factor Deck QOC?

Discussion in 'Lawn Mowing' started by mtmower, May 3, 2012.

  1. GMLC

    GMLC LawnSite Platinum Member
    Posts: 4,353

    mtmower look at the bottom of page 39 in your owners manual. There is note about pitch and cut quality. If I understand it correctly you are correct about rear pitch creating more vacuum.
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  2. Ridin' Green

    Ridin' Green LawnSite Fanatic
    Male, from Michigan
    Posts: 13,398

    Well, I don't have any way to scan them, but several of my Deere manuals show what I am talking about with descriptions and drawings etc. The forwards pitch is so that the blades are only cutting at the front edge of the blade, and it allows the vacuum affect to happen at the rear of the deck as you move forward, which also draws the grass in the direction of travel. The air is being forced out the side chute at high velocity, so drawing it in at the opposite side of the deck (rear) makes perfect sense for maximum air flow to happen. If it drew it all in at the front, it would be immediately redirected out the side chute and you'd have far less, if any, vacuum since the baldes wouldn't have a chance to create any suction anywhere except for the very front of the deck. This is nothing new that I am talking about here. There are lots of recent posts here about this as well.
     
    Last edited: Jun 2, 2012
  3. GMLC

    GMLC LawnSite Platinum Member
    Posts: 4,353

    In the Gravely manual it says pitching the deck creates more engine power to cut grass. Heeling the deck creates better cut quality. Gravely recommends a 1/8" pitch for the best balance.
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    Last edited: Jun 2, 2012
  4. Ridin' Green

    Ridin' Green LawnSite Fanatic
    Male, from Michigan
    Posts: 13,398

    Yea, that's a common pitch number. Deere shows anywhere from 1/8"all the way to as much as 1/2" depending on the exact mower deck and machine. Most manu's show 1/4" as std. A too steep pitch will leave furrows where each blade passes over the grass, but it takes an extrem pitch to do that. Also, remember that manu's show what will work for their decks under any all around conditions/regions. Playing with the pitch can really make a difference in your stripes depending on your exact grass types, and climate. down south, less may pitch may work best, but if you take a poll here, you'll find most guys are pitching their decks 1/4" or slightly more for the best looking cut and stripes (in northern climes).
     
  5. GMLC

    GMLC LawnSite Platinum Member
    Posts: 4,353

    Yea all my scag manuals recommend 1/4".
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  6. mtmower

    mtmower LawnSite Bronze Member
    Posts: 1,115

    Well it looks like everything is pointing toward adding more pitch than 1/8' that it's set at now to possibly eliminated the few stragglers I have here and there. I'll give it a try and see what happens. Thanks for the schooling.

    Has anyone adjusted a 400 series deck yet? I'm also confused on the need for blocking under the deck for the process as it says in the owners manual (not on the edge guard but on the lip of the deck). I just dropped the deck to the 3.5" mark like they recommend and used my new John Deere blade height gauge I bought for less the $7 and adjusted side to side then front and back on both sides and rechecked. The blocking of the deck they talk about in the manual makes no sense to me. If the deck is supported by blocks how in the heck do you get a reading?

    By the way I also found that the surface your on has to be dead pan flat or things are thrown off more than you'd think. The concrete surface I'm using I thought was as flat as any and found out differently when I started chasing my tail around the deck adjusters.
     
  7. Ridin' Green

    Ridin' Green LawnSite Fanatic
    Male, from Michigan
    Posts: 13,398

    Yep, I've posted the whole process of trying to use the gauge on cement here several times in the recent past. Almost any cement has small birdbaths that can throw the readings way off. When I built my shop a couple years ago, I made sure that they poured me at least 1/4of it dead flat and as dip/hump free as is possible with wet cement so I do have a good area to check mine over. Still, I lay my 6' trim level across it in several places to reassure myself every time I set a deck for level/pitch.
     
  8. GMLC

    GMLC LawnSite Platinum Member
    Posts: 4,353

    I dont want to confuse things but I think you would want less pitch per the Gravely manual. More pitch is going to give you more engine power(less vacuum). More heel should increase cut quality(more vacuum). At least thats how I understand it after reading the manual. Personally I would try leveling it first before heeling to see if your going in the right direction. Now that I think about it it makes sense. Think of the blade like an airplane wing. If the blade is pitched down in the front it creates down force. If the blade is heeled down in the rear it creates up force.
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    Last edited: Jun 3, 2012
  9. ProStreetCamaro

    ProStreetCamaro LawnSite Platinum Member
    Posts: 4,123


    You got it. If the deck is absolutely perfectly level flat it will create the most vacuum and cut the cleanest.
     
  10. ProStreetCamaro

    ProStreetCamaro LawnSite Platinum Member
    Posts: 4,123

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