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Bolt grade for blade?

Discussion in 'Lawn Mowing' started by Vibe Ray, Mar 8, 2001.

  1. Vibe Ray

    Vibe Ray LawnSite Senior Member
    Messages: 785

    Which grade bolt is the best for the blade bolt that holds the blade to the spindle?
  2. bob

    bob LawnSite Platinum Member
    from DE
    Messages: 4,260

    Did you get your ZTR yet?
  3. Grateful11

    Grateful11 LawnSite Member
    Messages: 177

    I think most decks use Grade 5, that's 3 marks on the head. You could just as easily use grade 8, that's 6 marks on the head. The 8's would wear down slower than the 5's and would probably cost 50% more. I like to put a little anti-seize on mine and torque them.
  4. Eric ELM

    Eric ELM Husband, Father, Friend, Angel
    Messages: 4,830

    The bolts that come with it should be heavy enough. As Bob said, did you get it yet?
  5. mowingmachine

    mowingmachine LawnSite Senior Member
    Messages: 253

    What size bolt does it come with and also what size blade is on the machine. Does it have a blade saddle or is it friction held. I would assume it comes with a grade 5 at least that is what most manufacturers use as standard hardware.
  6. mowerman90

    mowerman90 LawnSite Bronze Member
    Messages: 1,491

    Go with grade 8. Better to be safe than sorry. Pick'm up at any hardware store or Home Depot.
  7. mowingmachine

    mowingmachine LawnSite Senior Member
    Messages: 253

    Grade 8 is a much harder bolt then grade 5 but that is why I asked the question about blade size and whether it is supported in a saddle or friction held. Being a harder steel means a more brittle steel that when shock loaded will crack instead of bend. Basically a harder steel is more brittle and not as flexable. If the bolt is say 1/2" or greater I would be satisfied and feel safer with a grade 5 bolt. I would rather stretch or bend a bolt then break one. Just my thoughts.
  8. Vibe Ray

    Vibe Ray LawnSite Senior Member
    Messages: 785

    Yes Mowing machine, that is what I am talking about....Which grade is the best combination of hardness and softness for a mower blade. Grade 8 is not necessarily better than a grade 5 in all applications. That is why I am asking which grade is the best for LAWNMOWERS.
    MowingMachine or anyone else who knows, it is for a Lazer HP not quite sure yet what the bolt size is, so just name the best grade for all the possible size bolts for a mower blade bolt
    Bob, I should get it in about a week......can't wait!!!
  9. Ssouth

    Ssouth LawnSite Senior Member
    Messages: 436

    grade 5 for exmark, that is what came from the factory on both of mine. I have bought extra bolts that are 1/2 in. longer for double blades and the regular lenth. IN both cases I purchase grade 5.. I am sure exmark did research so I am sticking with what they use.
  10. Vibe Ray

    Vibe Ray LawnSite Senior Member
    Messages: 785

    Thank you Ssouth......anyone else?

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