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  • Steel Recomendation

    What would be the best grade steel to use for making pins for a small backhoe bucket. Pins will be 1 1/4" dia x 8" to 10" long, drilled and tapped for grease fittings and passages.

    Thanks,
    Frank

  • #2
    What are the bearings or sleeves made of? If there's no bearings, it's easier to replace a pin than a sleeve. In that case, use a cold rolled or W-1.

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    • #3
      Induction hardened chrome cylinder rod,failing that B-7.

      I would not use anything that is dead soft,the pins will pound out in an instant.

      On the subject of grease holes,I don't like drilled pins.The cross hole is where those pins always snap.It's much better to put the grease zerks in the working bushing and leave the pin blank.
      I just need one more tool,just one!

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      • #4
        <font face="Verdana, Arial" size="2">Originally posted by wierdscience:
        Induction hardened chrome cylinder rod,failing that B-7.

        I would not use anything that is dead soft,the pins will pound out in an instant.

        On the subject of grease holes,I don't like drilled pins.The cross hole is where those pins always snap.It's much better to put the grease zerks in the working bushing and leave the pin blank.
        </font>

        I agree with weird, at the shop we would use 4140, we stock that and its tough.

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        • #5
          you want a case hardend part for wear resistance in the bushings and meduim hard core to support the case and take the shock loads.

          8620 is perfect for this.
          Ignorance is curable through education.

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          • #6
            Well, ok. In my mind I was thinking of a Cad Digger or similar home-grown bucket. ... Like the Kenbota!

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            • #7
              4140 pre-hard should work well.
              James Kilroy

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              • #8
                Thanks for the tips. I didn't want to use cold rolled, at least without it being case hardened. I was thinking of using 4140 prehardened or the chrome cyl rod, they are both listed in McMaster-Carr.

                The customer definitely wants the grease fittings in the pins (same as original). The grease fittings are at both ends, extending in about 1" to 2" on each side. I could handle drilling in hardened steel, but tapping for the grease fittings could be another story. Are the 4140 prehardened and cyl rod drillable/tapable at the center of the diameter?

                It is a small machine. The original standard bucket is 12" wide. He is getting an 18" or 24" for occasional wide jobs.

                Frank

                [This message has been edited by PolskiFran (edited 02-02-2006).]

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                • #9
                  The 41xx series pre-hard is only in the range of 30-35RC. Plain ole W-1 drill rod (as milled) is 35RC. You should be able to drill it easily.

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                  • #10
                    4340

                    good enough for the wrist pins on an F111a swing wing fighter - should be able to handle a backhoe bucket in the cold.

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                    • #11
                      Yes,both can be drilled and tapped.The 4140-B7 can be milled,drilled,turned all over.

                      The hard chrome has a rc58-65 outer skin on the od that depending on type(75,000psi or 100,000psi)will be either .032" or .065" deep dropping off from that point to rc20-25 near the center.No trouble drilling/tapping the ends,the center is dead soft,almost gooey,lots of cutting oil/tap magic recomended.The od requires carbide to get through/under the skin.

                      If you didn't need to drill it another alternative would be linear shafting,they sell it too in pieces as short as 3" long and diameters to 2".

                      I just need one more tool,just one!

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                      • #12
                        Make sure you check your measurements, I know the small Hitachi's and John Deere excavators use 30 mm pins at the bucket end. I'd hate for you to find out it's a metric size after you order imperial. (Just in case)

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                        • #13
                          Thanks for the help. I'll be ordering monday. I'm working on new side plates and quick attach rig now.

                          The pins are not metric, I checked. Thanks for reminding me.

                          Frank

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