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Will this work? (bending die)

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  • Will this work? (bending die)



    That is the part. It is 1/4" x 3/4" wide A36 steel.

    This is the fixture I plan to bend it in. I give 1/16" on each side for springback, I plan to use it in my shop press. I will have guides on the fixture set up to ensure that the top and bottom of the dies stay aligned properly. I will also snug everything up so there isn't so much edge clearance...basically, just enough slop to keep it from binding.

    Anybody done anything similar?

    Any guess as to the force needed?


  • #2
    I think the ends of the work piece will curve because that is where the initial contact will be. The result will be a slight S-curve.

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    • #3
      It looks well thought out. I like the way you've thought of the springback on the ends.
      Using the round stock will make an "S". A triangular die would define the bends more.
      The only thing I see you having a bit of trouble with is the distance you'll lose when the top corner(of the bottom) of the bar flattens out. This will pull it away from the stop you'd need on the end to keep it in place.
      A bit of adjustment is all it'll take to get that right.
      Geez.. I hope that makes sense!
      Russ
      I have tools I don't even know I own...

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      • #4
        Very interesting

        Way cool Snowman, You gotta let us know how it turns out, maybe need some tweaking along the way --- Things to consider; What about an angle instead of the step at the ends for springback? generally I would not worry about what DP said if the part getting bent on the end is much longer than the part being held, with identical material throughout the leverage ratio will always favor the end piece and the deformation should always occur inboard -- but youv got other fish to fry here, your piece is of course going to "shrink" in the fixture while your doing all this (anotherwords all your contacts will be loaded in other directions along with the initial one your utilizing to bend with) And also your abrupt step for the spring back will start off at the ends but then as progression proceeds it will get loaded between the end and where you want the bend to occur --- with these other forces involved it could produce an S effect between the two..
        As far as the piece moving away from its stop as it progresses I dont see a problem as the dowels will become the anchor and the ends will do the moving, so if your stop is set correct you will indeed "shrink" the part away from your stop but should remain neutral throughout,
        The dowels will get loaded and with the slightest bends will keep the piece from moving from one side to the other all while the end pieces are in direct opposing battle --- should be good but an angle on the end for spring back instead of a step will also disable a notchy grab point and possible bend distortion.

        Edit; almost looks like something you could set up in the ole Kurt vise? might have to build special jaws?
        Last edited by A.K. Boomer; 05-04-2008, 10:12 AM.

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        • #5
          how many parts are you making? or is it a one off?

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          • #6
            A lot, if it was one or two, I'd do them one at a time with my redneck press brake

            I'm not overly worried about the S, the tolerance for parallelism of the two faces is probably +/- 1/16 to 1/8, it's just a weldament.

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            • #7
              Ought to work fine,tonnage should be less than 3tons assuming the drawing is to scale.
              I just need one more tool,just one!

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              • #8
                No, sorry it is not because of the mood i am in today.
                It will not follow the pressurepoint like you want them to but it will bend just like a pine board in a nice s-wave.
                Done a lot of good enough bending in the vice.
                I think it will work if you do one bend at a time, but that was the whole idea wasn't it?

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                • #9
                  i've got a few ideas, but im kinda busy at the moment if your still looking for help/info tommorow ill add a bit more, gotta think about it a bit first tho, been a looooooong day today

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                  • #10
                    It won`t work very well.You will get an S bend between the bends.Also when the top tool comes down it will contact the top end of the workpiece and spring the other end out of position.
                    Unless you have thousands to do it would be a better looking job done one bend at a time in a vee.

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                    • #11
                      Originally posted by Mark McGrath
                      Also when the top tool comes down it will contact the top end of the workpiece and spring the other end out of position.
                      That's why I mentioned the block at the bottom. That will hold it until the dies equal out.. no?
                      If you hold a straightedge through the dies you'll see it has to bend the top down about 1/4" before both dies make contact.
                      I have tools I don't even know I own...

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                      • #12
                        I dont see the flat ends coming out perpendicular. Gonna need a 1/4 plate on the press plates, top and bottom to be able to over press the stock. Just on the outsides of the rounds, maybe by a inch or so. JR
                        My old yahoo group. Bridgeport Mill Group

                        https://groups.yahoo.com/neo/groups/...port_mill/info

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                        • #13
                          I've used this same set up in a bench vice to put a 1/2" offset in a piece of 3/16"x1-1/2". I had to do a 10 part run and was quite surprised at how well it worked. The legs were parrallel without any curling, certainly good enough for a weldment within your tolerances.

                          Mac
                          Mac

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                          • #14
                            Originally posted by JRouche
                            I dont see the flat ends coming out perpendicular. Gonna need a 1/4 plate on the press plates, top and bottom to be able to over press the stock. Just on the outsides of the rounds, maybe by a inch or so. JR
                            JR... look close.. he has provided 1/16" "overbend" on the ends. I missed that at first also.
                            I have tools I don't even know I own...

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                            • #15
                              Maybe this?

                              This may give you better control over the finished part. The blank lays flat and the bending is applied to the part equaly over the whole blank. The red shows the blank in the starting position. You will also have better control of the over-bend.

                              Have fun,
                              Bob G

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