Results 1 to 9 of 9
  1. #1
    Platinum Member Furu's Avatar
    Join Date
    Nov 2009
    Posts
    770
    Location
    Washington
    Tractor
    JD 4720

    Default Sharpening Blades w/o hollow grinding them

    I have searched to see if I can find a thread on this and have not.

    When dealing with large thick brushcutter blades (Woods BB-720)and chipper blades how does one avoid a hollow ground profile when using a grinder that has a normal size wheel? I have only been able to do it with hand sharpening and would like to do it the more advanced and less labor intensive way.
    The steel blades are 0.5 inches thick and are ground at a couple of different angles (different on chipper and brushcutter)
    JD 4720 - 400CX FEL, Woods BB-720 Brush Bull and BH90X backhoe, Salsco 6210XT PTO Chipper, Farmi 501 Logging Winch, Bo-Dozer Grapple, LP RBT4096, Cammond Road grader/leveler and Rankin Trash Forks

  2. #2
    Elite Member smstonypoint's Avatar
    Join Date
    Oct 2009
    Posts
    3,967
    Location
    SC (Upstate) & NC (Piedmont)
    Tractor
    NH TN 55, Kubota B2320 & RTV 900, Bad Boy Outlaw 61" ZTR

    Default Re: Sharpening Blades w/o hollow grinding them

    I will be following this thread with interest.

    I have no direct experience in sharpening chipper blades, but I am in the market for a chipper and have been doing some research on sharpening the blades. Two dealers have told me that proper sharpening requires some specialized equipment. Here's a thread that discusses some of the issues involved:http://www.tractorbynet.com/forums/a...harpening.html.

    Steve

  3. #3
    Super Star Member
    Join Date
    Mar 2008
    Posts
    10,017
    Location
    Northern Fingerlakes region of NY, USA
    Tractor
    Kubota L3830GST, B7500HST, BX2660

    Default Re: Sharpening Blades w/o hollow grinding them

    For a rotary cutter, I would use a angle grinder while the blades are on the deck.

    Aaron Z
    A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
    Robert Heinlein, Time Enough for Love

  4. #4
    Veteran Member banjodunn's Avatar
    Join Date
    Jun 2008
    Posts
    1,201
    Location
    Oz

    Default Re: Sharpening Blades w/o hollow grinding them

    Quote Originally Posted by aczlan View Post
    For a rotary cutter, I would use a angle grinder while the blades are on the deck.

    Aaron Z
    x2 or if access is difficult while on the mower then remove and grind them in a bench vice


    Jon

  5. #5
    Veteran Member
    Join Date
    Feb 2001
    Posts
    1,444
    Location
    South-central Michigan
    Tractor
    New Holland TC40D

    Default Re: Sharpening Blades w/o hollow grinding them

    Hand held angle grinder. 4-1/2" works OK, but for taking a lot of metal off such as on a brush (rotary) cutter, I'd use a 7" or 9" instead. These will all result in virtually no hollow ground.

  6. #6
    Silver Member
    Join Date
    Dec 2007
    Posts
    180
    Location
    Coventry, CT
    Tractor
    Kubota B7800

    Default Re: Sharpening Blades w/o hollow grinding them

    or perhaps, a belt sander/grinder. Flat platen, easy to get belts,
    quick to use, and safe. Don't grind on the side of a round wheel.
    It's a great way to explode the wheel.
    Bill Hoffman
    B3030HSDC with loader, quick hitch, rear blade, rear rake, boom pole, clamp-on forks. Kubota Zero turn mower, Cadet 1811 w/MMM and a bunch of other stuff.

  7. #7
    Gold Member
    Join Date
    Oct 2009
    Posts
    288
    Location
    Fleming Island,FL
    Tractor
    John Deere 2006 4320 CUT, 1970 Power King 2416

    Default Re: Sharpening Blades w/o hollow grinding them

    What is the downside of hollow grinding bush hog rotary cutter blades? That is the way I always sharpen those on my Rhino bush hog. I think we had a discussion some time back regarding this. I do not grind the blades to a sharp edge. I leave an eighth to three sixteenths radius on the edge, which is I think what the book calls for.

    Jim

  8. #8
    Platinum Member Furu's Avatar
    Join Date
    Nov 2009
    Posts
    770
    Location
    Washington
    Tractor
    JD 4720

    Default Re: Sharpening Blades w/o hollow grinding them

    Hollow grinding can result in a much sharper edge but also somewhat weakens the blade by thinning it. As you point out the manuals specify a method for sharpening. Flat grinding is one and the 1/16 to 3/32 edge is another on the brushcutter but the chipper wants an actual sharp edge flat grind. IAW the manual.
    JD 4720 - 400CX FEL, Woods BB-720 Brush Bull and BH90X backhoe, Salsco 6210XT PTO Chipper, Farmi 501 Logging Winch, Bo-Dozer Grapple, LP RBT4096, Cammond Road grader/leveler and Rankin Trash Forks

  9. #9
    Platinum Member RoMad's Avatar
    Join Date
    Oct 2010
    Posts
    554
    Location
    Lecanto Florida
    Tractor
    Kubota L3710

    Default Re: Sharpening Blades w/o hollow grinding them

    When I sharpen my bush hog blades I do it with the blades on and use a 4" grinder. I hold the grinder somewhat flat. It would be really hard to do it with the grinder held at 90 degrees to the blades even if you wanted to. I suppose it might hollow grind the blades a little, but you can't see it with your naked eye. I also leave about a 3/32" to 1/8" land on the cutting edge.
    One thing I do no matter what I am sharpening with my grinder is I never let it get so hot I can't hold my bare hand against it. I may be way off, but I don't see how you can change the temper in any blade if you don't let it get hot enough to burn your bare hand.

Similar Threads

  1. Mowing Sharpening blades on a MX6...
    By c460053 in forum John Deere Owning/Operating
    Replies: 9
    Last Post: 08-22-2010, 12:49 PM
  2. Mower blades
    By Ferdd in forum Welding
    Replies: 4
    Last Post: 07-06-2010, 12:41 AM
  3. Mowing Replacement Mower Blades for BX
    By techguy2 in forum Kubota Owning/Operating
    Replies: 8
    Last Post: 03-01-2010, 01:44 PM
  4. mmm blades
    By Kevin Peterson in forum Kubota Owning/Operating
    Replies: 3
    Last Post: 09-18-2007, 08:52 PM
  5. Rotary Cutter Reattaching Rotary Cutter Blades
    By MikeGross in forum Attachments
    Replies: 7
    Last Post: 08-28-2001, 12:37 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
© 2014 TractorByNet.com. TractorByNet is a registered trademark of IMC Digital Universe, Inc. Other trademarks on this page are the property of their respective owners.