Noob warp repair

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I'm trying to make a tube bender, But apparently I made some mistakes. It seems that both of my uprights are tweeked when they need to be near perfectly parallel. When I slide a 7/8 solid bar, that passes between them, it lands about 1/16 low on the opposing upright. From the opposing upright, back, about 1/16 high. So they are both swayed in the same direction.My question is, how can I bend it back just abit. I don't have a torch here. Should I rent one and read up on straightening with that? Or is there a way I could heat them with the tig, and somehow bend or shrink them back? This is about the heaviest thing I have here, so I don't think I'm going to be able to bend it. Is my only option a pie cut and reweld?I don't want to grind/file the holes to much, so I need  to straighten it a bit.The uprights are exactly that. The two parallel bars that are vertical. Sorry about the bad pic. I could post more if you want or need. The bars are 2x2" .250 square tube, mild steel. And ideas, held would be greatly appreciated. Thanks.
Reply:I built the same bender recently , and basically ran into the same problem..Had to run through some of the holes with a dremel tool,just moving it around in a circular motion, for the pin to be able to go in My problem was some of the holes were drilled slightly off,Make sure your holes are drilled dead nuts first As for the torch (and a bfh), it MIGHT be a pain in the *** with those 45 degree reinforcements, so you may need to cut the welds out of those before doing that..But if you do that you may as well grind down the welds on the uprights, and get them as square as possible .Pins through as much holes as you can and heavy clamping anything you can.. Tig torch doubt that would heat it up enough Good luck  Here is mine, as you can see in the photo the pin isnt all the way through, the photo was taken before I made a bunch tweaks ( i had to make alot including cutting off and redoing the upper brackets on the upright)
Reply:Originally Posted by ak4130I built the same bender recently , and basically ran into the same problem..Had to run through some of the holes with a dremel tool,just moving it around in a circular motion, for the pin to be able to go in My problem was some of the holes were drilled slightly off,Make sure your holes are drilled dead nuts first As for the torch (and a bfh), it MIGHT be a pain in the *** with those 45 degree reinforcements, so you may need to cut the welds out of those before doing that..But if you do that you may as well grind down the welds on the uprights, and get them as square as possible .Pins through as much holes as you can and heavy clamping anything you can.. Tig torch doubt that would heat it up enough Good luck Here is mine, as you can see in the photo the pin isnt all the way through, the photo was taken before I made a bunch tweaks ( i had to make alot including cutting off and redoing the upper brackets on the upright)
Reply:ANd another thing I want to add . as you can see the grey (galvanized scrap) swingarm in my picture has 2 sets of holes..That is because I made them based off the prints, before I got my die..When I got my die it didnt fit at all ( a 7/8" 3 clr), so I had to flip them around  and redrill.I had to redo the upper brackest as well.So if you dont have any dies yet may want to order one  before you start fitting all this other stuff..Ya need it anyways
Reply:Originally Posted by bkivi99Hey how much did that cost to make? That is sweet.
Reply:If you have TIG you can use that as a heat source and just slowly run across tube heating it to a dull red instead of welding.  It is difficult to tell you where to put the heat.    I suggest you put a two foot straight edge against the tubing to see if it is bent or if the problem is down and the base tube connection.  If the verticals are straight then you can apply heat on the underside of the base tube duplicating the welds on the upper side of the base tube.  Let it all cool to room temp and check with a straight edge.  Most important is not to rush in and start heating without knowing what you want to straighten.
Reply:Are you sure it is warped/tweeked? Could you holes be off?  If it is tweeked, then why not just take it apart/cut it, brace(compensate), tack, tack, tack, check and reweld.  Not much to take apart, there.  If holes are misaligned, then file as needed.
Reply:AK4130; I have my die, but I hope to get others. And I didn't check it yet, which I should have. But I may have to do the same thing - flip and redrill.Tapwelder & Lotechman; The tubes were perfectly square and the holes were machined, not drilled, so they were pretty much perfect when I started - even the base of the uprights where milled to a perfect 90. I tacked them all inplace, checked to make sure it was square, slid the bar out, and welded it up - so I'm guessing it's warped from heat somewhere. Which I'll findout where. It's not to much, at the third hole from the bottom, the round bar that slides through the machined hole lands 1/16 off on the opposing tube, which is 4.5" away. They're both swayed the same direction. So if I apply heat, till red, what's it going to do? Expand, then contract smaller that what it was as it cools, or the opposite? Is this a black art of guessing how much it's going to contract?Is the mistake I made going for every seam that was easy for me to get to then switching location, as opposed to welding them in a symetrical fashion though out the whole job? Or applying to much heat on the tubes that get a tube butted to them? Or does somthing like this need to remain jigged as long as possible?Either way, there's something in experiance I'm missing here. Clue me in? I could probably grind the holes alittle bit here on this project, but I plan on making components of thinner steel(mostly .120), and I want perfect tolerances, and if avoidable, I don't want to make a jig for every component I build, as I intend to make a lot of one-off components, and don't know that I can afford the time or stock to make a jig for everything. Is it possible to do perfect structures without jigs?Thanks guys.
Reply:Remember metal usually pulls in the direction it's welded. So if you weld on one side 1st, chances are it will pull that way. There are dozens of ways to combat this from the begining. There have been any number of threads on keeping welds square. Lots of this partially comes down to experience. You start to get a feel how much something may move, and can start out slightly positive in the other direction so it pulls straight.As far as heating and shrinking, search some of Farmersamm's posts on shrinking. You heat the opposite side and then quench it with some water to get it to pull back. It is somewhat of a black art getting it right. I've seen guys do it with no trouble and some who just end up with it 10 times worse than when they started..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:I think DSW hit the nail on the head. A hard lesson on clamping and the importance of tacking and measuring everything square before just having at it and welding it all up
Reply:Depending on what you're building, say a lot of welding on one side, you can heat shrink the opposite side before you ever start welding. Knowing where to heat shrink is one thing, knowing how much heat to apply is where experience shines! Don’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:i don't think it's so much a black art is it is trial and error experience. as DSW and others have stated heat an area on the back or opposite side of the bend and i would heat in a V about half way down on the sides. all to a dull red and on the first attempt i would let it air cool naturally. check it with a straight edge and gauge how much it straightened. if not straight you can repeat the process until it is straight. it is better to straighten it in small increments until you get experience in the process than it is to over do it and have to remove what you over did. also once you become better acquainted with straightening you can try cooling quicker to pull more bend out using wet rags, a squirt bottle such as a windex bottle with water or my personal favorite, compressed air and blow gun. another method you can use not having a torch would be to try and wedge a hydraulic bottle jack, porta power or even a bumper jack between the frame and apply a little force to the back side of the bend and rap the side of the bend with a hammer to relieve the stress. you don't have to carried away an smash it with a 16lb sledge. a one pound ball peen works wonders. it may take a few times but it works. be very very careful to not put to much pressure on the jack and don't stand in the direction the jack will go if it slips out. also it's a good idea to alternate sides if both legs are bent, hot or cold straightening. good luck.Last edited by jbmprods; 08-23-2011 at 03:37 AM.225NT bobcatAEAD200LEScott 125mm175, mm252 w 30A, PT225mm211, TA 181iHyper Therm 380, cut master 529100X & XX, Digital Elite6 Victor setssmith little torch, meco midget kalamazoo band sawsteel max saw evoulution circular saw
Reply:Here's a good example of heat shrinking before welding. If you've ever built a manifold you'll know how much it can warp, especially if all the weld is on one side!   Attached ImagesDon’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:I found this book a pretty good reference. Welding Fabrication and Repair: by Frank Marlow  [ame]http://www.amazon.com/Welding-Fabrication-Repair-Questions-Answers/dp/0831131551[/ame]$30 well spent.  There are some pretty good discussions on bending metal with heat, as well as LOTs of other stuff tied to welding for fun and profit..   My copy sits in the porcelain throne room for handy reading.. zip..
Reply:that is a very good book. definitely worth the price.225NT bobcatAEAD200LEScott 125mm175, mm252 w 30A, PT225mm211, TA 181iHyper Therm 380, cut master 529100X & XX, Digital Elite6 Victor setssmith little torch, meco midget kalamazoo band sawsteel max saw evoulution circular saw
Reply:You can check out some of that book. http://books.google.com/books/about/...d=UT5HM71MHe8CThey use to have the full chapter of  bending.  Oh well should have had the problem 2 yrs ago. It was quite informative.
Reply:This is worth a read:Flame bending
Reply:Sorta had the same post awhile back and ordered this same book and a couple of others that were represented on here and I just got the book, has alot of info in away even a "Shade Tree" welder like me can understand. Got it from Amazon..Miller 252 Mig w/Spool GunMiller Dynasty 350 TigMiller 225 AC-DC StickMiller Spectrum 875 PlasmaOxy/Acet.
Reply:Originally Posted by ak4130Plans were like 15$ I think Steel tubing (20-24 ft 1/4" 2x2 ) was about-150$ Alot of  the other steel 1/2" hrs was free scrap from a dumpster Ram was about 85$ on sale Misc 5/8" bolts and stuff The die was around 200$   If I were to do it again I would order a die before anything and build the frame for it around the holes in it  based on whatever metal is available..Because at this price I could have bought a commercially made bender..But without the air hydraulic jack.. 1 advantage is it bends the tubing vertically so no need to secure it to the floor , and it was a fun build
Reply:Thanks guys. I'll definately be ording the book and reading up on flame bending more. I'm clearly going to need to master and better understand heat warping and bending to get where I want to be at with my fabrication goals. Originally Posted by missfireWhere did you get the plans from, Thanks
Reply:Hammer.Cheap!
Reply:Read this, alot of my work is sheet metal but I would bet you are not going at it methodically, and symmetrically. Attached ImagesQ&A-17 How to Carry Out Tack Welding.pdf (79.5 KB, 30 views)