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another for the engineers

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  • another for the engineers

    does this create a "bad " bending force on the vertical members of the press ? (side view,rough sketch)

    http://bmw625.imgur.com/all/

    bmw

  • #2
    "bmw625's images are not publicly available. "

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    • #3
      I think I fixed that. I like it better when I can just post an attachment directly ! bmw

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      • #4
        That will try bending the vertical columns apart. They need to be either really rigid or braced with something or ou have to tie them together from the top.
        Amount of experience is in direct proportion to the value of broken equipment.

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        • #5
          okay, as long as the headstock and the bed pieces are both on the same side of the verticals (inside or outside) it works fine but it will bend even though the cylinder pushes on the center between the bed pieces ?

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          • #6
            Originally posted by bmw625 View Post
            I think I fixed that. I like it better when I can just post an attachment directly ! bmw
            Like this?

            Home, down in the valley behind the Red Angus
            Bad Decisions Make Good Stories​

            Location: British Columbia

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            • #7
              The vertical rails need to be I or H beams. The slightest bit of off center loading will bend the vertical rails of the press frame.

              Edit: An I beam would be a better choice than an H beam as the resistance to bending forces comes from the depth of the web between the rails. You could make the rails out of U channel. A reasonable approximation for the web in that case would be for it to have a cross section area at least as great as the cross section of the rails. So for example a 3x1.5 U channel could work but a 3x2 would be better.
              Last edited by jlevie; 01-17-2014, 12:19 PM.

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              • #8
                Originally posted by Willy View Post
                Like this?

                how do I post the image directly like that ? I have one more

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                • #9
                  There are several things unclear in the sketch.

                  First, if there is a single rod going all the way through the front and back holes in the bed and frame, things will likely be OK.

                  I had one hydraulic press that operated with four separate round posts that worked well.

                  However, the amount of deflection you get in the verticals will directly depend on how stiff the top beam is. If it bends under load, it will try to throw a bend into the verticals.

                  There is also the question of how the bed rails are atttached together. The bed needs to be as stiff as the head beam and something needs to tie the front bed rail to the back bed rail and keep them from bowing out or trying to roll out.


                  for what it's worth, take a look at the cheap Chinese presses and you will see about the minimum you can get away with.

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                  • #10
                    Originally posted by bmw625 View Post
                    how do I post the image directly like that ? I have one more
                    This site will not host an image so in order for you to directly post an image it must first be on another site that does.

                    Since you already have a host for your pictures I just went to your link where the image resides, copied and pasted the web address in the "insert image" icon on the advanced reply page.
                    Give it a whirl, you can check your progress by clicking on the...preview post..button before you post your reply

                    There's much more info on this subject on the sticky about how to post pictures with Photobucket, you'll find near the top of the general forum.
                    Home, down in the valley behind the Red Angus
                    Bad Decisions Make Good Stories​

                    Location: British Columbia

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                    • #11
                      thanks Willy, I was getting confused so I created an account and linked. don't usually post pics,the times I do it is a forum that lets you post directly

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                      • #12
                        Draw where you think your force vectors are
                        then re-post. It looks OK to me as it is. No
                        need for anything other than rectangular flat
                        bar for the uprights.

                        --Doozer
                        DZER

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