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fabrication of helix out of tubing, how do you do it?

Discussion in 'The Hokey Ass Message Board' started by 31Vicky with a hemi, Jan 14, 2012.

  1. I've built some crazy stuff in my time.
    Augers, ribbon mixers, spiral staircases so I'm pretty hip to the helix shape.
    I really tried hard to find you guys a better picture but I couldn't..that leads me to believe its pretty rare . Maybe it hasn't been done yet.

    Ok so when you look at this pic, you might have to squint some or take off your glasses. Try to see this as 4 pieces of tubing wrapped around each other & fitting tight. I know that's a rotor from a blower, please don't tell me how to make that. Lol just look at 1/2 of it and see some 2" tubing. 4 separate tubes, 180* helix about 36" long.
    How do you do it ?
    Turn the pipe while its going thru a roll bender? ? ?


    [​IMG]
     
  2. We buy twisted tubing in smaller sizes already made up. I know a blacksmith hear in town that twists his own. He welds the tubes to a plate on each end and then twists them. I know that is the simple answer but it can be done. By the way his twisting machine is huge.
     
  3. I bet huge is an understatement. I tried exactly that with some way smaller tubing and that was next to impossible to twist and when it did it flattened out.
    Got a name and number for the guy.
     
  4. threeston
    Joined: Sep 26, 2010
    Posts: 74

    threeston
    Member

    just saw this technology. Its called a picket twister.
     

  5. If two inch is what you need I can check on Monday to see if it is avaliable. Do you mean four two inch tubes or two inch od total?
     
  6. 4 separate 2" tubes.
     
  7. Ruiner
    Joined: May 17, 2004
    Posts: 4,141

    Ruiner
    Member

    Stack the 4 tubes in a square, fill the tubes with sand, weld a square plate on both ends, build a ring burner to fit around that mess and heat the shit out of all 4 tubes in one section, twist them a little and move down...repeat for about 3 hours until you get to the other end :p...it's possible with the sand packed in you won't need heat...you could also torch out a flat plate with 4 holes in a cloverleaf pattern to use as a wrench to twist the tubes...no idea if any of this would work, just bouncing ideas around...
     

  8. Thats the approach that immediatly came to my mind as I was reading the previous posts.

    Shrapnel :cool:
     
  9. Bump for the morning crew
     
  10. The ring roller idea sounds good. If you're using exhaust tubing (I'm guessing headers), you may run into crush problems. Anything heavier than about 095 is going to be a cast iron bitch to get any permanent torsion into without heat, so you've got a pretty narrow window on material.

    I've done some twists using a standard rotary draw bender with the one-pull method, but only on smaller diameters. If you leave the pinch bolt loose and rotate the tube after each pull, you'll get a helix...but it takes some real dialing in; and getting 4 of them to nest will be tough. It may also leave the tubes "lumpy" as you are pushing the tube through an inch or 2 between pulls.

    I've never been big on sand packing, but this might be a good time for it.
     
  11. RodStRace
    Joined: Dec 7, 2007
    Posts: 3,908

    RodStRace
    Member

    The previous suggestions sound like a good possibility.
    Another setup might include a 4-headed torch that could extend into the tubes from the stationary end and apply heat from the inside.
    I keep seeing the tubes collapsing or burning through.
    Since it should be a continuous curve, why couldn't all 4 be bent on the same form and then slid together? The math for that curve is beyond my level, but it should be able to be calculated and each tube formed.
    I picture a large chunk of metal or wood with the inner tube curve cut into it and a guide slot on the other side. On the outside, a short section of sleeve that has a peg to fit the guide slot and the outside of the tube curve. You will need to heat the tubing to elastic, and have the main form solid mounted. Lay the red tubing into the form and use the ring to draw it to shape.
     
  12. Well ill try sand packing some 1" conduit for a test to see what happens.
     
  13. Dale Fairfax
    Joined: Jan 10, 2006
    Posts: 2,585

    Dale Fairfax
    Member Emeritus

    I think the roll bender is the answer--maximum radius; slight offset of the two bottom rollers.
     
  14. tommyd
    Joined: Dec 10, 2010
    Posts: 11,948

    tommyd
    Member
    from South Indy

    Subscribed. Those will be some wicked headers!
     
  15. Ruiner
    Joined: May 17, 2004
    Posts: 4,141

    Ruiner
    Member

    I could be wrong, but I don't think he's making headers...at least I hope he's not making 36" long header tubes, you'd have to have one hell of a long intake to make those even remotely perform properly...
     
  16. When we buy the pretwisted stuff it usually has a solid rod taking up the space in the middle. I don't how they do it but it is twisted cold. No heat marks. I will let you know what I find tomorrow. By the way how much twist do you want?
     
  17. squirrel
    Joined: Sep 23, 2004
    Posts: 55,938

    squirrel
    Member

    Bending tubing is a LOT easier than twisting it.
     
  18. realkustom51
    Joined: Nov 14, 2005
    Posts: 664

    realkustom51
    Member

    I got to help install a 25ft Pines Bender in just down the road from you in Natural Bridge, Va.. It used this type of tooling so the tubing being feed over it could also be bent with no collapse or wrinkles. Like chucking a piece of tubing in a 20' lathe, and rotating it as you feed it over the tooling.
    Axis 1 = Rotating the tubing.
    Axis 2 = Feeding the tubing over tooling.
    Axis 3 = Roller at end against tubing producing radius.
    [​IMG]


    To make a "Coil" , 2" tubing, about 12.000 radius, shaped like a spring.
    Axis 1 = Constant CW
    Axis 2 = Feed 20 ft per minute
    Axis 3 = Radius 12.000

    To make a shape like you want (I think)
    Axis 1 = Constant CW
    Axis 2 = Feed 40 ft per minute
    Axis 3 = Radius 36.000

    Just thinking that a guy with a pines bender could spit out 20 ft of tubing in 5 minutes and then you could cut it up in sections. In a perfect world I guess.
     
  19. Technically it is rolled if it is single piece. Rolling a spiral that tight requires a pretty special machine. The smallest we have rolled is about three feet diameter and that took a lot of force. It has to be pulled as it is rolled. When you twist four tubes together it works like twisting square stock.
     
  20. Checked my sources this morning and the largest premade I can find is 2 11/16". I talked to my blacksmith buddy and he said he can do it. PM me and I will give you the info. You might look around in your area to see if you can find a blacksmith with the equipment.
     
  21. 1950ChevySuburban
    Joined: Dec 20, 2006
    Posts: 6,187

    1950ChevySuburban
    Member Emeritus
    from Tucson AZ

    Bang a tube of Pillsbury biscuits on the counter and unroll the tube. Is that the shape you're looking for?
     
  22. Lol, no that's not it but thanks
    Pretty much explained to the first post.

    Thought I'd get to the sand bend today but that didn't happen.
    Tomorrow
     
  23. wearymicrobe
    Joined: Jul 27, 2007
    Posts: 265

    wearymicrobe
    Member
    from San Diego

    Little off the wall but tube filled with sand and welded on each end, then take it to someone local who makes truck/industry springs.

    They will have powerful enough gear driven lathes that can bend the material and the mandrels and spacers that you would need to get the spacing correct. The math is going to be tough though and you would have to build in some tolerance for the expansion of the metal and rebound after heating.

    Make four seperate tube twists then place them together.
     
  24. RodStRace
    Joined: Dec 7, 2007
    Posts: 3,908

    RodStRace
    Member

    Like this, but only 4 tubes... not cable
    [​IMG]
     
  25. realkustom51
    Joined: Nov 14, 2005
    Posts: 664

    realkustom51
    Member

    I am going to be in front of one of those Pines multi axis benders on Thursday next week. I am going to form up a 10' piece of the tubing like you described. I will cut the 10' piece into 2-1/2' pieces then group them in a "Twizzler Candy" fashion. This is my plan anyway.
    If successful, I will post a picture.:)
     
  26. wearymicrobe
    Joined: Jul 27, 2007
    Posts: 265

    wearymicrobe
    Member
    from San Diego

    Good luck, I did not know that the Pines system were independent three axis. If so that opens a lot of doors for fabricating custom steam piping for me.
     
  27. Id like to see that for sure.

    My attempt at sand bending with heat started to work, but the 1" conduit ripped itself apart at the ends. I can see it might work, but ill have to figure a better attachment method.
     
  28. It may seem counter intuitive but it is eaiser to form heavy wall tubing. It will hold it's shape better. You should not need sand. It just takes a lot of power to twist.
     
  29. A long time ago we used to build spiral staircases and had to bend round tubing into a spiral for the handrail. We had a piece of heavy pipe with a section of allthread in the middle (for adjustment)with swiveling angle iron saddles on each end that we used to bend the handrail over in small steps around a central pipe. You have to tack braces in place as you go. Granted that it was a larger bend radius than you're talking about, but maybe that sort of approach might work, doing one tube at a time (very carefully) then twisting them together. Sorry this isn't very easy to explain but if you've done spiral staircases, I think you understand the principle.
     
    Last edited: Jan 23, 2012
  30. Last edited: Jan 23, 2012

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