Help Squaring Tubing

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I do a lot of welding on tubing, usually 1-1/2" or 2" 14ga or 11ga. I always miter the angles unless the drawing specifically shows them not mitered. I've gotten pretty good at keeping an enclosed rectangle (like for a table top) perfectly square after welding, but I cannot seem to EVER get a table leg square. Here's my procedure, maybe someone can point out where I'm going wrong:I place the leg on the table top, slightly lean it inwards, tack weld the outside corner. Then I square it up on one axis and tack weld the adjacent corner to the original tack to prevent movement in the squared axis. Then I square up the other direction and tack the other two corners. I can keep the leg straight up until this point. Is it just a matter of heat control and distribution that's messing me up? I wish there was a formula for how to get perfectly square table legs!I've seen a couple hints on other posts about heating a weld to a dim red and applying some pressure in the direction you want it to bend. I guess I could play around with this, but I only have a MAPP torch. No O/A yet, so heating takes way longer than I'd like it to. I do have a carbon arc torch but I'd be afraid of doing too much damage with that.John 3:16(2) Miller Pheonix 456(2) Millermertic 252Dynasty 210DXHobart 210MVPDoringer D350 SA Cold SawScotchman 350LT Cold SawWebb 10x50 MillWebb 15x40 LatheGeka Bendicrop Ironworker
Reply:Yep, you answered your own question. That is going to draw when you weld. Brace or put in a jig or like you said play with it. Figure about how much it will draw and go form there, if freehand. Otherwise add more tack welds and brace. Perfection is more times than not unattainable. Settle for excellence you'll be happier.Arcon Workhorse 300MSPowcon 400SMTPowcon SM400 x 2Powcon SM3001968 SA200 Redface1978 SA250 DieselMiller Super 32P FeederPre 1927 American 14" High Duty LatheK&T Milwaukee 2H Horizontal MillBryan
Reply:Don't bother with Acetylene for heating, too expensive.  Get a large/appropriate tank and tip for heating.
Reply:Originally Posted by blawlessYep, you answered your own question. That is going to draw when you weld. Brace or put in a jig or like you said play with it. Figure about how much it will draw and go form there, if freehand. Otherwise add more tack welds and brace. Perfection is more times than not unattainable. Settle for excellence you'll be happier.
Reply:NEVER HEAT A WELD WHEN HEAT SHRINKING!!!!!!!!!!!!!!!!!!!!  You'll ruin the metallurgy of the weld!!  Always heat the steel adjacent to the weld, or somewhere along the tubing away from the weld to straighten it.You'll always get some heat in the weld when working close to it, but NEVER GET IT CHERRY RED.  Weld filler composition is very different from the base metal.  You can make the weld brittle, or anneal it, or....................."Any day above ground is a good day"http://www.farmersamm.com/
Reply:Tubing that size and thickness won't take any heat at all to move. It's when you get into beams, and thick plate where you'll need a lot of heat. 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 also do lots of tubing work but for gates and pens. have you tried the bessey 2 and 3 axis welding clamps? a big time saver. square and plumb every time with no heating.i.u.o.e. # 15queens, ny and sunny fla
Reply:So I just heat the area near the weld that needs to be bent and just let it cool and it will move? Or am I supposed to apply some pressure to it?John 3:16(2) Miller Pheonix 456(2) Millermertic 252Dynasty 210DXHobart 210MVPDoringer D350 SA Cold SawScotchman 350LT Cold SawWebb 10x50 MillWebb 15x40 LatheGeka Bendicrop Ironworker
Reply:I always use a spry bottle for little things. For beams I use a garden hose. But you don't have to! You can just let it cool on it's own. 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:How do you know how much it will move? Is that something you just get a feel for?John 3:16(2) Miller Pheonix 456(2) Millermertic 252Dynasty 210DXHobart 210MVPDoringer D350 SA Cold SawScotchman 350LT Cold SawWebb 10x50 MillWebb 15x40 LatheGeka Bendicrop Ironworker
Reply:For Miters you should compensate some but for butt joints like a tube t'ed into the frame you should just brace and weld. It may move some but that will be the frame warping up around the tube. It sounds like you set the leg leaning a little essentially creating a small gap then you tack there. Then you lean it the other way making another small gap and tack again. It sounds like by the time you are done tacking it that you will have a square to frame leg that is sitting on a small gap with a bunch of tacks holding it. Then welding will just cause lots of molten metal to go under the tube and cool and shrink a bunch causing it to pull out of whack. If the tube is held square right up against the frame and you are not doing a 100% penetration weld but just a fillet then the cooling, shrinking weld will be restricted by the tube. No gaps are your friend. Not sure if that is what is happening but gaps shrink a lot when filled with weld. There is also always some movement when welding but in this instance you deal with it afterwards or clamp everything real well.Millermatic 252Lincoln 175 plusTA 185tswTA 161stlhypertherm pmax 45Victor torchHenrob torchAn S10 for each day of the week
Reply:Originally Posted by EcondronHow do you know how much it will move? Is that something you just get a feel for?