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  • Bending tube or pipe

    I need to create a half-circle out of ~1.25" square tube or pipe to form the top section of a gate. The segment needs to be bent to a diameter of 6'.

    The tube/pipe is not structural - decorative only. In fact, the lighter the better as this is decorative only. Can this bend be done in 1.25" square tube (no kinking)? Or is this a job for pipe ?

    Related question - is the bending feasible "by hand" (with home made jigs). If not I have a machinist down the road with a bender that will roll 2" plate into a 24" dia circle - or so he claims.

    Thanks,
    -Mark

  • #2
    While it is possible to bend it by hand, if you have access to a bender that will roll it, so much the better.

    Comment


    • #3
      Location matters. Post up yours. If you're local I'd say come on down to the shop and have at it.
      Miller 251, Lincoln PrecisionTig 275, Miller DialArc 250 AC/DC, Hypertherm 900, Bridgeport J-head, Jet 14" lathe, South Bend 9" lathe, Hossfeld bender with a collection of dies driving me to the poorhouse, Logan shaper, Ellis 3000 bandsaw, Royersford drill press and a Victor Journeyman O/A.

      Comment


      • #4
        By hand is tough. Artsy and kinda fun, though.

        Tubing and to a lesser degree, pipe is going to want to collapse and kink like a soda straw and the notion that heat will help is pure fantasy.. don't waste good O/A jacking around trying. Filling the cavity, however with tightly packed sand or better yet, molten lead will aid in keeping the cross sectional profile.

        I have had good results with the following techniques:

        To the top of a good work bench fixture two hard points with rollers and a jack working perpendicular to them, like an arrow to a bow. Use a string and a piece of chalk and draw a full size guide on the floor. Work a little bit at a time and check it against the guide after every go.

        Sectioning and welding works good for an arch that size. If done carefully it will yield results equal to or better than the best ring rollers. I have a formula I worked out for number of and placement of cuts if you decide to try it. The downside is all the clean up.

        If you chicken out I'll make the piece for you and ship it. I have a rig I built that can do one of those pieces in a couple of minutes.
        Mike

        sigpic WHEELED VEHICLE SERVICE SINCE 1960

        Comment


        • #5
          You need to use tube. Do not use pipe. Minimal wall thickness .058"
          For tube you can get a 5.5" radius, 180 degree bend, out of mild steel DOM tube with .060" wall. I wouldn't waste time packing it or heating it. You need someone that has a tube bender, and you can get the results you are looking for. My tube bender doesn't kink or crimp the tube.
          If you were closer, you could bring by the tube you need bent, but that would be a long drive.

          -Ryan
          PowerMig 215
          Precision Tig 225
          Old Buzz Box

          Hypertherm 600
          HH 125 EZ
          MM 350P
          TB 302 w/ 12RC


          Originally posted by scab
          If you are the type of person who gets upset at things breaking brace yourself for possible dissappointment.

          Comment


          • #6
            I'm in Lakeview, just south of Vass on US#1.

            I have one of these -

            http://www.harborfreight.com/cpi/cta...emnumber=99736

            and I turned some dies to roll square tubing -

            http://www.millerwelds.com/resources...t=18060&page=3

            Send me a PM.

            Comment


            • #7
              Originally posted by ace4059 View Post
              ...You need someone that has a tube bender, ...
              Ryan
              A ring roller would be faster and create a smoother bend than a tubing bender. The largest dies I've seen for tubing benders for small 1.25" tubing are far smaller than a 3' radius.

              Dave
              Still building my new old truck - see the progress!
              http://www.ford-trucks.com/forums/65...-coe-idea.html
              http://www.hobartwelders.com/weldtal...ad.php?t=27017

              Square Wave TIG 200 - Woot!
              MM180
              SP125+

              Comment


              • #8
                Chuck, How well do your set screws keep the collar from sliding when the tube tries to spread?

                Dave
                Still building my new old truck - see the progress!
                http://www.ford-trucks.com/forums/65...-coe-idea.html
                http://www.hobartwelders.com/weldtal...ad.php?t=27017

                Square Wave TIG 200 - Woot!
                MM180
                SP125+

                Comment


                • #9
                  Open this link and scroll down to roller to see how one was built.

                  http://metalworking.com/dropbox/_2001_retired_files/

                  Gold mine of projects there. http://metalworking.com/

                  Comment


                  • #10
                    whateg0 -

                    I just made the dies so I don't have a lot of experience with them yet.

                    Before I made the adjustable dies I turned a set of 3/4" fixed dies.

                    They pinched the tubing when I bent the 3/4" sq 16g tubing you see in the pics.

                    I had to tap (not beat !) the tube out with a hammer.

                    Not bad for A 12" radius I'm thinkin' !

                    With the adjustables' I can leave 'em loose and they work fine.

                    Comment


                    • #11
                      That's cool. When I made my dies for bending square tube in my press, I had to loosen the sides to get it to let go. How do the one-piece dies work? Are they just not as tight? Or is it normal to have to persuade the workpiece out?

                      Dave
                      Still building my new old truck - see the progress!
                      http://www.ford-trucks.com/forums/65...-coe-idea.html
                      http://www.hobartwelders.com/weldtal...ad.php?t=27017

                      Square Wave TIG 200 - Woot!
                      MM180
                      SP125+

                      Comment


                      • #12
                        Guys - this is great input thanks.

                        I'm still at the "feasibility stage" so nothing to bend yet. I'll need to do some mockups of the final construction to make sure the proportions aren't overwhelming: 6' wide gate/arbor prolly 11-12' tall in 2x2 square tube.

                        -Mark

                        Comment


                        • #13
                          Originally posted by whateg0 View Post
                          A ring roller would be faster and create a smoother bend than a tubing bender. The largest dies I've seen for tubing benders for small 1.25" tubing are far smaller than a 3' radius.

                          Dave
                          I'm sorry. I miss read the above OP. I thought he wanted a 6 inch radius bend. I looked over it and he wants a six foot radius bend. My fault, when I first looked at it I could see it. That was my reason for recommending the tube bender.

                          But YES since the bend needs to be 6' (and not 6") a ring roller would be the best.
                          PowerMig 215
                          Precision Tig 225
                          Old Buzz Box

                          Hypertherm 600
                          HH 125 EZ
                          MM 350P
                          TB 302 w/ 12RC


                          Originally posted by scab
                          If you are the type of person who gets upset at things breaking brace yourself for possible dissappointment.

                          Comment


                          • #14
                            whateg0 -

                            I cut the 3/4" one piece dies without considering sideways expansion so on a

                            tight radius they're snug.

                            I could trim 'em up a bit if need be.

                            Comment


                            • #15
                              http://www.metalgeek.com/archives/2005/05/01/000047.php
                              here you go this may be of use.
                              glen, been there, done that and probably broke it!If you aren't on the edge. You'r taking up to much room

                              Comment

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