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What grade of bolts?

Discussion in 'Fisher Engineering Discussion' started by Banksy, Nov 17, 2007.

  1. Banksy

    Banksy PlowSite Veteran
    Messages: 3,113

    What grade are the bolts from Fisher that bolt the mount to the truck? Grade 5 or 8? I'm just going to get some bolts from Tractor Supply and tac weld on handles to make install easier.
    Should I use any other washers than the standard lock washer or no washers and a nyloc-nut? What's the preffered combo? Thanks.
  2. Midwest BuildIt Inc

    Midwest BuildIt Inc PlowSite.com Addict
    Messages: 1,280

    not sure about the washers, but mount bolts are usually grade 5, that way they sheer before you cause any frame damage. I would probably go with the nyloc's .
  3. Wicked500R

    Wicked500R Senior Member
    Messages: 394

    A couple 3/4" grade 5 bolts will still cause other carnage before shearing. What I have seen in the past is that the grade 5 bolts over time can wear out and become eggshaped causing slop in the frame. I have also seen them bend. I use all Grade 8 hardened with washers and Nylocks when it comes to these type of applications.
  4. I just put a boss mount on my truck and SOME were grade 5 and SOME were grade 8. You should probably call fisher or check their website!
  5. Banksy

    Banksy PlowSite Veteran
    Messages: 3,113

    Fisher doesn't seem to specify what grade on their site. They show torque specs for 5 and 8, but the instructions don't say what to use when bolting the mount on. I'll try to call Fisher.
  6. JD Dave

    JD Dave PlowSite Fanatic
    Messages: 11,034

    Just use grade 8 if your worried about it, the price diff is minimal. I would use flats and lock nuts but that's just me.
  7. Banksy

    Banksy PlowSite Veteran
    Messages: 3,113

    Fishers site shows flat washers and locknuts. So that's what I'll use. Thanks.
  8. Banksy

    Banksy PlowSite Veteran
    Messages: 3,113

    From what i can tell the stock bumper bracket bolts get reused to help hold the mount on. Then I have 3 more holes that need to be drilled and bolted. So, maybe 3 grad 8's would do the trick.
  9. mcwlandscaping

    mcwlandscaping 2000 Club Member
    Messages: 2,557

    Fisher specs grade 5, i used grade 8's on my plow rebuild, ALL plowside hardware was under $8 bucks, there isn't much on the plowside! Grade 8s are sold at $3.83 a pound at TSC near me

    Truckside will be a bit more as there are A LOT of bolts on the mounts! :)

    JRKRACE Senior Member
    Messages: 172

    I just got a new bolt kit from Fisher (28.00) and they were all Grade 5...
  11. Banksy

    Banksy PlowSite Veteran
    Messages: 3,113

    I saw that Fishers bolt kit used grade 5, so that's what I went with. Thanks.
  12. TurbDies2500

    TurbDies2500 Senior Member
    Messages: 188

    I use grade 8 on all of that stuff. just my preference tho
  13. sparky8370

    sparky8370 Senior Member
    Messages: 234

    I just bought all grade 8 for mine. Don't know if it will really cause a problem. I bought used mounts of ebay, then got the installation guide off fisher site. It called for grade 5. If I hit something hard enough to shear the grade 5, I figure I 'll have bigger problems than bending the frame.
  14. tkrepairs

    tkrepairs Senior Member
    from maine
    Messages: 186

    i used all grade 8 to mount the plates to the frame of the truck. working at a hardware store has its advantages for availability to fix stuff :)
  15. Santry426

    Santry426 Senior Member
    Messages: 419

    Is there somewhere I can order the fisher hardware? Just picked up a set of used 7169's and need the hardware
  16. RacingZR

    RacingZR Senior Member
    from Maine
    Messages: 398

    Last mounts I put on were all grade 5 bolts. I also got a "kit" from a local Fisher parts dealer. Grade 8 would be fine though. If you're snapping grade 5 or grade 8 bolts on the push plates, you have bigger issues than selecting the wrong bolt type..............
    FYI- I loctited and double nutted mine to make sure they didn't come loose.
  17. 2COR517

    2COR517 PlowSite Fanatic
    Messages: 7,115

    Double nuts are the way to go. Nylock is not suitable here IMO, except when used as a lock nut behind a properly torqued standard nut.

    "I routinely apply the maximum allowable torqueage....."
    Last edited: Nov 29, 2009
  18. naturalgreen

    naturalgreen Senior Member
    Messages: 404

    I use 8s not sure why other than I prefer overkill than wear out. If I hit something and my bolts are too strong then Im an idiot but yet to see that prob. I would use washer, lock washer and double nut. I have issues. I dont like lock nuts for these apps.