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5to 1 formula for box offsets of any size

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    5to 1 formula for box offsets of any size

    Hello everyone. Does any one know of a 5 to 1 conduit formula for box offsets of any size pipe? Guys at work mentioned it today and I remember hearing something about it before. I don,t know if it applies strictly to electric and hydraulic benders or if it may have something to do with the travel on those benders. any advice would be appreciated.

    #2
    I use a 2 to 1 with 30deg offsets for hand benders

    2" offset 4" between marks, 30 deg bend @ each mark. Think this came from an uglys book.

    Been so long since I used any other bender I couldn't tell you otherwise.
    Tom
    TBLO

    Comment


      #3
      The ratio used depends on how many degrees of bend you are using not what type of bender used or raceway size. Drawing a triangle to represent your offset you will have a constant that changes when the angle changes. The ratio should be the length of the hypotenuse of the triangle to the side that represents the amount of offset. Use trigonometry to find unknown length when you know the angle and offset distance. 5:1 is not very much bend probably 10 degrees or even less.
      I live for today, I'm just a day behind.

      Comment


        #4
        From a spreadsheet I set up some years ago.

        Tried to post spreadsheet

        total offset angle of bend distance
        1 5 11.47
        1 10 5.76
        1 15 3.86
        1 20 2.92
        1 22.5 2.61
        1 25 2.37
        1 30 2
        Last edited by ptonsparky; 07-29-10, 07:58 AM. Reason: didn't work
        Tom
        TBLO

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          #5
          still didn't work right
          Tom
          TBLO

          Comment


            #6
            Originally posted by ptonsparky View Post
            TOTAL


            ANGLE OF
            DISTANCE
            OFFSET
            BENDS
            A <-> B
            1.00
            5.00
            11.47
            1.00
            10.00
            5.76
            1.00
            15.00
            3.86
            1.00
            20.00
            2.92
            1.00
            22.50
            2.61
            1.00
            25.00
            2.37
            1.00
            30.00
            2.00
            1.00
            35.00
            1.74
            1.00
            40.00
            1.56
            1.00
            45.00
            1.41
            1.00
            50.00
            1.31
            1.00
            55.00
            1.22
            1.00
            60.00
            1.15


            From a spreadsheet I set up some years ago.
            I'm guessing your original format did not copy the way you had it? I think I see the number of degrees and the multipliers but that 1.00 keeps getting in there - must be another field that stayed constant in the spreadsheat.

            add: for the OP the multiplier of 5 is between 10 and 15 degrees of offset according to this spreadsheet 10 degrees is 5.76 multiplier, 15 degrees is 3.86 multiplier.
            Last edited by kwired; 07-29-10, 08:06 AM.
            I live for today, I'm just a day behind.

            Comment


              #7
              I think 5* would put you right at 11 deg

              5.76 is 10 deg

              http://www.bing.com/search?q=emt+off...=QBRE&qs=n&sk=

              there are a few good reads on line

              Comment


                #8
                If you can see it you can bend it... they also have formulas on the sides of new benders. If we are talking about the same box offset, it seems to me, they are too small to consider measuring.
                "Never give in, never give in, never; never; never; never - in nothing, great or small, large or petty - never give in except to convictions of honor and good sense"-Winston Churchill

                Comment


                  #9
                  Those were all for a 1" offset. For a 3 inch offset using 5 deg bends your marks would be 34.41" apart.
                  Tom
                  TBLO

                  Comment


                    #10
                    There are 2 approaches that I'm aware of: starting with a known ratio and determing the angle of bend or starting with a known angle and determing the ratio.

                    1) sin^-1(1 / (ratio desired) = angle of bend

                    or

                    2) csc(angle desired) = ratio

                    So in this case, use formula 1 and get:
                    sin^-1(1/5) = 11.537`

                    Comment


                      #11
                      Originally posted by tld38 View Post
                      Hello everyone. Does any one know of a 5 to 1 conduit formula for box offsets of any size pipe? Guys at work mentioned it today and I remember hearing something about it before. I don,t know if it applies strictly to electric and hydraulic benders or if it may have something to do with the travel on those benders. any advice would be appreciated.
                      Do you mean 6 to 1?

                      10 degree bends require 6" between marks for every 1" of offset. I usually use 10 degree bends for box offsets myself.

                      Comment

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