Blade Balancing

Discussion in 'Lawn Mowing' started by Scott H, Apr 30, 2001.

  1. Scott H

    Scott H LawnSite Member
    Posts: 58

    How important is it to balance your blades after sharpening them?
    What kind of damage can be caused by not balancing them?


    Thanks,
    Scott H
     
  2. Eric ELM

    Eric ELM Husband, Father, Friend, Angel
    Posts: 4,831

    It is very important to balance the blades. Not being balanced causes vibration which in turn puts extra wear on bearings which causes spindle bearing failure. I have seen brand new blades that are so out of balance, it is unbelievable. I balance all my blades, new and old. I put them on the balancer before sharpening so I can find out which end is the heavy end. Be sure to clean any buildup off the blades too, to get a correct balance.
     
  3. Mr.Ziffel

    Mr.Ziffel LawnSite Senior Member
    Posts: 291

    I use Eric's ball bearing blade balancer which I copied off his web site [click red house on his post]. I talked to the Exmark technical rep about this subject and he said they've seen mower decks which had the top steel deck plate on the point of being completely cracked through in a circular pattern due to unbalanced blades being used. The blades would cause the spindles to wobble and rather than cause the spindle to fail, would cause the whole top deck plate to set up a circular vibration causing stress around the entire spindle mounting area. Could you imagine the deck failing and the spindle dropping out at 19,000 feet per minute? Ouch!

    I think Eric has a great list of posts on blade sharpening but I've thought there should be a step by step procedure listed so here's how I do it, using a RGB brand blade grinder.

    1] Scrape any grass and built-up accumulation from blade. I use the side of a steel 4" putty knife.

    2] Flatten back side of blade with file [10" mill bastard] This usually takes only a few swipes and guarantees you have a flat surface to slide on the grinder table. I have had some so banged up I used a hand-held angle grinder to smooth the backside.

    3] I set my RBG at a slightly steeper angle than on a new blade, so that it takes off just a thin shiny line of material from the lower portion of the bevel of the new blade. Exmark says the blades should be ground at 27 degrees. I leave the grinder at this angle for all blades, even on different brands of mowers cause it's easier.

    4] I make between 3 and 6 passes [depending on depth of nicks - I hit a lot of gravel] on each end of blade and check balance, then take material off the heavy side accordingly. When I first started doing this I ground metal until the whole bevel was shiny, but now I stop grinding as soon as I have a shiny line the length of the whole cutting edge on both sides.

    5] Final check for balance and into the pile it goes! Hope this helps, Will
     
  4. AB Lawn Care

    AB Lawn Care LawnSite Senior Member
    from Ontario
    Posts: 585

    Hey eric it's great to see my blade balancing idea has made it to you web site....I could not find it do you have a link to the section with the balencer????I have not been on the fourm much lately becouse i'm so busy.I'm glad to see that idea is helping others.

    Oh ya my Walker is now up too 1000hrs repair free...what's your dixie at????? :)
     
  5. Highpoint

    Highpoint LawnSite Member
    Posts: 153

    Just my 2 cents. We have never balanced a blade in over 15 years. Can't say as I have had any bearing failures, vibration, or any thing else for that matter. Maybe I should try and balance a set and see if there is any measurable differences. 2 machines, 6 blades, nothing else better to do, go for it! 14 machines, to many blades to count or worry about. Just doesn't seem to be an issue. Not to argue the point. Balance or not to balance. You'll have to figure it out. Happpy Days.
     
  6. Eric ELM

    Eric ELM Husband, Father, Friend, Angel
    Posts: 4,831

    Adam, it's good to see you posting again. :)
    Here is the link to the post I did on the balancer. That is the most precission balancer I have used. ;)
    http://www.lawnsite.com/showthread.php?threadid=869

    You asked about my Choppers, I have 3,278 on the old one and 382 on the 2001 diesel Chopper. The grass is growing like crazy here now. We have had enough rain to get it going and keep it growing.
     
  7. AB Lawn Care

    AB Lawn Care LawnSite Senior Member
    from Ontario
    Posts: 585

    I allmost forgot about that thread!I still just have mine on the wall.I'll put the balancer on the grinder once I get the time........which right now is hard to come by.

    hmmmmm.....3728......DANG!

    Well i'll have to work my way up to that. :)

    Take it easy eric!
     
  8. Scott H

    Scott H LawnSite Member
    Posts: 58

    Thanks for the help guys, I'll take a look at the blade balancer.



    Thanks,
    Scott H
     
  9. rixtag

    rixtag LawnSite Senior Member
    from Lehi Ut
    Posts: 280

    Eric, for us idgits would you mind giving apart list so I can build one of those great balancers? bearing size, bolt length etc... Thank you in advance.

    Rick
     
  10. AB Lawn Care

    AB Lawn Care LawnSite Senior Member
    from Ontario
    Posts: 585

    Pretty simple really.Its just a bolt,a few roller bearings and a nut.Eric made the idea even better by adding it to his RBG Grinder.I have a RBG as well but have not had time to put mine on the grinder.It will only cost you a few bucks at a hardware store and will save you alot in blowing bearings and giving a better cut.

    The main point is to make sure that it is mounted very level.

    If you are still not very sure how in the world to make this balancer here is a complete list of what to do.

    1.Take a blade off your mower.

    2.Drive to your local hardware store.

    3.Find 2 ball bearings that will fit in your center hole of your blade(the bearings should not be hard to slide in and out or be to small)

    4.Once you have found that,you now go and grab a bolt that will fit through the center of the bearings.

    5.Then grab 2-3 nuts.

    6.You can mount the balencer where ever you want just make sure to have it level.Eric has his on his grinder,I simply mounted it on a board on a wall next to the grinder.

    7.Drill a hole to the size of the bolt where you want to mount the balancer.

    8.Slide the bolt throught the hole and then take a nut and fasten the bolt to the area.

    9.Take an other nut and slide it on,then put the 2 bearings on and then put 2 more nuts on the bolt.

    10.Finally you have a blade balancer!Just make sure the bearing are in tight and the nuts are small enough that the blade can get to the bearings.

    Now if that was to hard to figure out you will have to email eric :)

    I also drew lines on the surface of where I mounted the balencer so I can make sure its is perfectly balanced.

    I first thought of the idea when I was looking to buy a balencer.There where your cheap cup balancers and other ones on the market,but nothing was too accurate.Then I found a balancer that held a blade on with a magnet.Basicly all it was is a few ball bearings ans a magnetic cone on the end.It cost a few hundred $$$ U.S.I thought,hey can't I build a balcancer for a few bucks and get the same results?When you mount the blade on the balancer the heavy side will drop down.You just keep grinding the blades untill you have either side that sits straight on the bearings.

    Sorry for the long post but I thought I would get it all out in 1 post so others can just read this in the future and not have to ask much more about the balancer.

    Hey Eric I still have not recived my royalty check from you yet!:)
     

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