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How are presses rated?

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  • How are presses rated?

    Are the tonnage rating based on the frame strength? Force source? A cheap hydraulic press uses a bottle jack, is the jack's rating the presses rating? What about arbor presses where human input on a lever is geared down, is that type of press rated by the frame/gearing strength? I recently picked up an unmarked arbor press and it got me wondering about these things.

  • #2
    I have wondered the same,I have a 25 ton Dake Arbor press and would be curious if a digital scale load cell would give accurate reading.Be cool if could watch readout go to 50000 lbs. by pulling on handle!

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    • #3
      The tonnage rating of a press takes into consideration both the maximum available force and the frame required to contain it--in other words, it's got to be a balanced system. Too much tonnage for the frame and you're gonna have a dangerous machine that will break at the least opportune moment; too little tonnage and you're wasting money on the frame. Still, the latter case is the better option...
      Keith
      __________________________
      Just one project too many--that's what finally got him...

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      • #4
        Depends on the Press !
        On a bridge type press, (what you call a ordinary shop hydraulic press) the rating is the stress of what the frame can take, and/or the limit of the hydraulic cylinder/system.
        On a bridge screw press, it will be the frame strength.
        On a Arbor press, you have a asymmetric frame that can spring, so you may have a rating based on frame strength OR it may relate to the non-perpendicular error that occurs under pressure ( some call it "spring")
        This is particularly true of industrial high speed presses called OBI's (Open Back Inclineable)
        Such presses use die sets and any spring would seriously damaged the punch and/or die

        Rich

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        • #5
          Originally posted by Tundra Twin Track View Post
          ..I have a 25 ton Dake Arbor press..
          Surely this is mistaken! A really big huge beefy arbor press might go ten tons. Surely you mean a 25 ton Dake press, right?

          metalmagpie

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          • #6
            Originally posted by metalmagpie View Post
            Surely this is mistaken! A really big huge beefy arbor press might go ten tons. Surely you mean a 25 ton Dake press, right?

            metalmagpie
            Don't call me Surely

            here's the thread he posted awhile back

            http://bbs.homeshopmachinist.net/thr...on-Arbor-Press
            .

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            • #7
              Originally posted by LKeithR View Post
              The tonnage rating of a press takes into consideration both the maximum available force and the frame required to contain it--in other words, it's got to be a balanced system. Too much tonnage for the frame and you've got a Harbor Freight product; too little tonnage and you're wasting money on the frame. Still, the latter case is the better option...
              Fixed it for you.
              Last edited by Fasttrack; 10-31-2016, 02:10 PM.

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              • #8
                The load rating is how much force you can apply to the part...the frame had BETTER be able to handle it.

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                • #9
                  Originally posted by SirLesPatterson View Post
                  Are the tonnage rating based on the frame strength? Force source? A cheap hydraulic press uses a bottle jack, is the jack's rating the presses rating? What about arbor presses where human input on a lever is geared down, is that type of press rated by the frame/gearing strength? I recently picked up an unmarked arbor press and it got me wondering about these things.
                  When I bought mine The spec was a 30 ton, US made frame and a 2O ton Chinese bottle jack. I cannot prove anything or speak about other presses but I guess that if the hydraulics are not built in, I would want to know how strong the frame is, so I don't over do it with the hydraulics. My frame is pretty massive.

                  Sent from my SM-G900V using Tapatalk

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