Page 2 of 4 FirstFirst 1234 LastLast
Results 11 to 20 of 32
  1. #11
    Veteran Member
    Advertiser

    Join Date
    Apr 2000
    Posts
    1,589
    Location
    Western New York
    Tractor
    Kubota B2710

    Default Re: Shear pin?

    Jag, I don't think you want to spray oil on any dry clutch. It would cause the clutch to not grip therefore slipping and in effect not work.


  2. #12
    Veteran Member
    Join Date
    Jan 2001
    Posts
    1,659
    Location
    San Francisco Bay Area California (CA)
    Tractor
    Kubota B7500

    Default Re: Shear pin?

    BMW,

    Go with John's advice, use the grade 2 bolts. You want the bolts to blow, not your equipment. Kinda like a circuit breaker in an electrical circuit: you want the fuse to blow before the wires melt (or catch fire [img]/w3tcompact/icons/shocked.gif[/img]!!!).


    The GlueGuy

  3. #13
    Epic Contributor Bird's Avatar
    Join Date
    Mar 2000
    Posts
    38,511
    Location
    Texas

    Default Re: Shear pin?

    <font color=blue>Go with John's advice, use the grade 2 bolts.</font color=blue>

    Amen!

    Bird

  4. #14

    Default Re: Shear pin?

    Just so everyone is clear, a grade 5 bolt has 2 lines on it. A grade 8 bolt has 5 lines on the head strike. A bolt without lines on the head strike is buyer beware, you don't know what you're getting, but it's probably soft, so it would have a lower shear strength than a higher grade bolt. The difference in grading primarily relates to tensile and shear strength and is derived from different alloys and heat treat processes. A properly designed shear pin protected drive train should have the shear pin fail as the first line of defense to damage, using a higher shear strength bolt puts the whole thing at risk for damage.


  5. #15
    Gold Member
    Join Date
    Apr 2000
    Posts
    444
    Location
    Central Arkansas
    Tractor
    Kubota /L2650/ LA450/B4690 -- John Deere 450 Dozer

    Default Re: Shear pin?

    Von, just a light shot to keep the rust away... What is best, slip to soon or slip to late...


  6. #16
    Veteran Member
    Join Date
    Sep 2000
    Posts
    1,371

    Default Re: Shear pin?

    Just to make it clear'er[img]/w3tcompact/icons/smile.gif[/img]

    <font color=blue>a grade 5 bolt has 2 lines on it. A grade 8 bolt has 5 lines on the head </font color=blue>

    This is from Thomas J. Glover, pocket reference on bolt grades.

    SAE Grade 0 -1-2 no lines
    SAE Grade 0 -1-2 no lines
    SAE Grade 0 -1-2 no lines
    SAE Grade 3 two lines
    SAE Grade 5 three lines
    SAE Grade 6 four lines
    SAE Grade 7 five lines
    SAE Grade 8 six lines

    Please note that just because a bolt is grade 2 does not mean
    it will break easily. Grading only refers to the minimum strength, not the maximum. Thus, if a machine uses a soft bolt as a safety shear pin, and you happen to replace it with a grade 2 bolt that was actually manufactured to grade 8 specs (but was marked down because too many of the bolts in the lot failed, so the whole lot was marked down) you could create some serious problems. Replace safety-related items
    with proper stuff! Also beware of improperly-marked forgeries.

    Al




  7. #17
    Veteran Member
    Advertiser

    Join Date
    Apr 2000
    Posts
    1,589
    Location
    Western New York
    Tractor
    Kubota B2710

    Default Re: Shear pin?

    Jag,
    But what if you now have constant slipping and have to buy new clutch packs? I still say no oil on dry clutchs with no exceptions! Unless you have money to burn on new parts every year. You are better off removing the pressure on the clutch pack so that rust will not be a problem.


  8. #18
    Veteran Member hayden's Avatar
    Join Date
    Sep 2000
    Posts
    1,709
    Location
    MA/VT
    Tractor
    Kubota L5740 cab + FEL, Cat D5G dozer, Kubota KX121 excavtor

    Default Re: Shear pin?

    Or for those of us who are memory impared - the grade is the number of lines plus 2.


  9. #19

    Join Date
    Apr 2000
    Posts
    349
    Location
    Peculiar, MO
    Tractor
    B2400 Kubota

    Default Re: Shear pin?

    Question: Is not the bolt markings molded into the bolt head when the formed? If so, how can a grade 8 be changed to grade two when bolt fails specs? Am I missing something?

    Dan L


  10. #20

    Join Date
    Aug 2000
    Posts
    239
    Location
    Texas
    Tractor
    my 18 horse Sears doesn't even count as a tractor

    Default Re: Shear pin?

    The grade designation comes from the automotive industry, their specification SAE-J429. There are ASTM standard bolting specifications that have compairable bolts. The problem with the two standards is that the marking requirements are different. An SAE Grade 2 for example has no markings, it also has two different strenght levels depanding upon the diameter of the the bolt. For 1/4 through 3/4 the bolt has a 74,000 psi tensile strength as a minimum, over 3/4 through 1 1/2 the tensile strength drops to 60,000 psi. The ASTM A307 is a compairable bolt (with no markings) but its minimum tensile strength is 60,000 psi no matter what the diameter. This is exactly like MarkJC stated, you don't know what you are getting and with a minimum tensile strength specification you can end up with bolts of the same grade with drastically different mechanical properties. I am going to scan a bolt head identification chart and will try and post it tomorrow.

    Randy


Page 2 of 4 FirstFirst 1234 LastLast

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.