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Cut Quality

Discussion in 'Lawn Mowing' started by jondcoleman, Oct 3, 2006.

  1. jondcoleman

    jondcoleman LawnSite Member
    Messages: 181

    I was wondering if someone could provide me with a list of adjustments on mowers that can affect cut quality and how they should be adjusted (i.e. Blade sharpness and angle, pitch, etc.). I feel like I am doing everything I know to do and am still not getting very good cut quality. It leaves blades of grass uncut throughout the lawn. It is not a lot but if you look at the grass at ground level you can definitely see it. Thanks for any help.
  2. pcarlson1911

    pcarlson1911 LawnSite Member
    Messages: 89

    without much information, I wonder if your lifting up the grass to the blades. Without enough lift, the grass will just lay down instead of getting cut.

    Of course this is a WAG since we don't know what your set up is.
  3. stumpjumper

    stumpjumper LawnSite Member
    Messages: 183

    Also consider that late season grass more difficult to cut. Have you had problems all year or just lately? I have had to double cut some lately for the first time this year with the same setup I've used all year.
  4. jondcoleman

    jondcoleman LawnSite Member
    Messages: 181

    What do you mean by lift? How could I increase it? I have my blades set at 3 1/4. It does seem like the grass is laying down. Thanks
  5. jondcoleman

    jondcoleman LawnSite Member
    Messages: 181

    Yeah, it mainly just started happening within the past month or month and a half. I did not know that it made a difference. Thanks.
  6. Nosmo

    Nosmo LawnSite Bronze Member
    Messages: 1,216

    What type mower are you using? Is it a ZTR if so what model and brand.

    Quote: What do you mean by lift? How could I increase it? I have my blades set at 3 1/4. It does seem like the grass is laying down. Thanks

    What he meant by this is what blades are you using ? Hi lift , med. lift , mulching or ???
  7. topsites

    topsites LawnSite Fanatic
    Messages: 21,653

    The reason the mfg's build mowers the way they do is because they want all mowers to be as safe as possible.
    This does not, unfortunately, provide the best performance.
    Thus what you do after you buy them is your own business and at your own risk.

    Here is what 'dials' my mowers in, but you need to be aware that this affects your height settings and it also makes your mower considerably more destructive (I'll explain in a second)...

    What I do is insert washers / spacers on TOP of the blade after the bolt goes through (so between the spindle and the blade) until the bottom of the blade is flush with the bottom edge of the deck's skirt. Basically I am dropping the blade out from inside that deck, I find a lot of manufacturers recess their blades way up in there, it is no wonder these mowers all streak! So, bring it down until the bottom of the blade is even with the bottom edge of the skirt (need pics?).

    This, more than anything, has fixed once and for all the stupid streaking issue, thou at speeds in excess of 6-7 mph there will still be some... Oh, and I ALWAYS run Hi lift blades.

    Now the warnings:
    1) This has a bit of a learning curve... Driving with the mowers as-is from the manufacturers tends to give us the impression that so long the deck clears an object, so will the blades... Once you have performed the above modification, your blades will NOT clear objects that the deck does, you will need to find out for yourself when an object is too high up (like a root, etc) and realize that you got yourself a straight razor that can and will scalp - practice makes perfect, it's not that big of a deal but you do need to be aware of it.
    2) If you have a dial setting or any other height set, you have effectively lowered your cut height and you need to adjust for this somehow (so if you lower your blade 1/4" then you might want to raise the mower 1/4" or set the cut height at whatever + 1/4" (so if you normally have it at 3" then set it to 3.1/4" to compensate).
    3) Last but not least, ensure you have enough thread left on the bolt to hold it in there (For spindle-held bolts I'd say at least 5 threads, or 1/2 an inch of bolt going inside... On mowers with nuts on top, the nut must thread completely).

  8. pcarlson1911

    pcarlson1911 LawnSite Member
    Messages: 89

    The shape of the blade can affect the lift, or the air current movingin the deck. A high lift blade Moves the air up inside the deck this lifts the grass with the air current, Whilethe grassis standing straight up, the blade swings by and wack. With highlift blade our mower deck is like a giant flow-bee.With low lift blades, the stiffness of the grass is the only thing that keeps it in the way of the blade.

    Lift is one of the biggest reasonsforthe cut quality of comm grade mowers. The blades are moving twice as fast as a consumer grade mower, probably at least twice as much lift.

    I run a Scag Tiger cub with a bagging system. the lifti s so awesome, that I rarely blow driveways, instead, I putthe deck down to 1 1/4" and suck it clean. It looks awesome.

    good luck.
  9. dvmcmrhp52

    dvmcmrhp52 LawnSite Platinum Member
    from Pa.
    Messages: 4,205

    A giant flowbee.......I like that......you're also dating yourself a bit.............

    Sharp blades, proper deck pitch for YOUR mower and conditions, proper blades,(high lift, medium lift, solid foil, notched foil) deck level, and a clean deck are a few things that create a quality cut.

    Sometimes you need to experiment with them to get what works for you on your machine.
  10. prostriper

    prostriper LawnSite Senior Member
    Messages: 336

    There is a few factors that can cause this.

    One of the main ones I have had happen is improper cutting edge angle. I have been hand sharpening for a long time and get it wrong from time to time. Take some old blades and practice, practice, practice. Compare the edge of your sharpened blade to a new blade until you find a "sharpening practice" that gets you the best and most consistent results. Or keep a few sets on hand and have them professionally sharpened, or purchase a blade grinder they start at about $400. Sometimes you can find one fairly cheap on e-bay.

    Another factor is deck pitch. Check your owners manual or call the manufacturer for the best pitch for your specific mower.

    You may also be cutting too much grass. If the grass is real tall 6" or more, your front tires may be laying the grass down to the point that the mower can't pick it back up. High lift blades can help a lot in this case. Cutting in thick grass at too high of a speed can cause this as well, due to the deck getting more grass than it can handle. If that is the case just slow down.

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