|
|
I am going to be stick welding the frame shown below (4 x 8 x 1/4 tubing) and would like to keep it as flat as possible and keep the "C" from opening or closing as much as possible. I had planned to tack the elements together at the corners with a 1/8" gap and then weld the short sides first. I have a 3/4" steel table top that I can clamp the frame to for welding the long sides. Should I weld the long sides in short segments and flip it over after doing each short segment?Any advise will be greatly appreciated.JimCut an MGB and widened 11" C4 Corvette suspension and LT1 Chevrolet power & 6 spd. Pictures here:Part 1http://forum.britishv8.org/read.php?13,7581Part 2http://forum.britishv8.org/read.php?13,22422
Reply:IMO you are asking about the correct tacking sequence to minimize distortion caused by weld shrinkage. If that's it, check out post #8 in this post on the miller website http://www.millerwelds.com/resources...highlight=warp for the photo inserted in that post. It shows the correct tacking sequence.ScottMiller XMT 350 CC/CV w/gas solenoid opt.Miller S-22A wirefeederBernard 400A "Q" gunMiller Spoolmatic 30A / WC-24C-K 200A torch/gas lensWeldcraft WC-18 watercooled torchHypertherm Powermax 30Victor O/A
Reply:I guess if it was me...I'd tack the long flat joints first, then the outside joints of the "c", then flip it over and tack the long flat joints, then finish up by tacking the inside joints of the "c". It'd be nice to tack alternate sides of the flat, but it's pretty heavy to hold upright to do it unless you have a way to do it.Weld the flat joints first on both sides (half length of joint at a time on each side, alternating side to side), then the outside joints, and finish up with the inside joints.Now that was pretty damn confusingYou're basiclly trying to equalize the pull as the weld shrinks when it cools"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Like this, is what I do usually Attached Images"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Oh hell, on second thought. (idiot!).Lay it out like you want the final form to be, tack the inside edges. The c will draw closed. Put a piece of scrap and a jack inside the c to spread it back out to a perfect c, or a little bit of a closed c, then tack the outside to pull it the other way. You can always grind the tacks off if they pull too much one way or another.Or lay the c out slightly open, tack the inside to close it up, then tack the outside.The do the flats as I figured in the first place.Either way, the final full welds will pull it some more.Seen comercially made things like you're making, and they generally take care of the distortion by mounting the tool holder thing to compensate for it."Any day above ground is a good day"http://www.farmersamm.com/
Reply:I better just shut up!!"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Make tacks in the 'middle' of any section to minimize warp (cooling and the associated contraction of the formerly-molten metal will thus tend to distort in only one direction/dimension).Lay your frame flat on your table, tack in the middle of the 'long' joints/seams, flip over and lay flat on the other side, recheck layout/dimensions and adjust as needed, tack on the middle of the 'long' joints/seams there. Recheck layout/dimensions and adjust as needed, tack in the middle of the 'short' joints/seams on one side, recheck layout/dimensions and adjust as needed, tack last 'short' joints/seams.Final preliminary layout/dimension check and adjust as needed (clamps, prybars, BFH, etc)The cyan 'dots' indicate the tack welds on the 'long' joints/seams.Then go about the welding. Attached Images The best laid schemes ... Gang oft agley ...
Reply:But we're still dealing with the final welds pulling the c open, or closed. There's gonna be shrinkage wherever there's heat. That's why I changed my mind on locking the long flat joints first. I figured to try and get the c as close to possible by utilizing the shrinkage on the end joints, then locking the long flat joints.I think the heat along the long joints will be easier to control by just welding on opposite sides to equalize pull. It's the unrestrained c that's the real problem.Does this make sense?"Any day above ground is a good day"http://www.farmersamm.com/
Reply:You either shrink to pull it in, or shrink to pull it open."Any day above ground is a good day"http://www.farmersamm.com/
Reply:I think I need to work small areas and compensate on the opposite side when it moves. As the welds fill in, the structure should become more rigid and resistant to distortion (I think). I'll tack the corners first and see what happens. Then tack the centers of the short and long sides. Probably try to do the finish welds in 1-2" lengths alternating from side to side. I'll let you know how it works.JimCut an MGB and widened 11" C4 Corvette suspension and LT1 Chevrolet power & 6 spd. Pictures here:Part 1http://forum.britishv8.org/read.php?13,7581Part 2http://forum.britishv8.org/read.php?13,22422
Reply:That's sort of what I argued myself into. I really don't know any other way than to see how it pulls, then retack it if necessary.It's an English Wheel isn't it? After you get the damn thing perfect, it's gonna be interesting to see how much the tool pressure spreads the c. I've never used one so I don't know"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Tack the corners. If you make them good tacks, the corners is all you will need. Then weld the longs sides first. Shorts sides first is guaranteed to pull the part. As the weld cools down it will shrink slightly (both the weld and the surrounding steel). Welding the short sides on the inside of the C will cause the C to close up (dimension across the opening will become smaller). Welding the short sides on the outside of the C will cause it to open up (dimension across the opening will become larger). Welding the long sides first will 'lock in' the C. It will still move a little bit, but this can easily be minimized. Lay the C on the table and weld all the 8" welds on one side. Flip the part over (welds you just made are now down), and clamp it to the table (very likely the center tube section will be sitting off the table a little bit, provided your table is flat). Weld the remaining 8" welds. Then weld the inside 4" welds, followed by the outside 4" welds. The reason for welding the inside first, is if it pulls, it's far easier to fix a closed C, than an open one. If it does pull, put a bottle jack into the throat of the fully welded (and fully cooled down) part and use it to adjust the part. Take a measurement of the C across the opening, and compare it to your desired dimension. Use the bottle jack to open the C up to the desired dimension, then let off the jack pressure to see how much it's going to spring back (it will, a lot). Use this to gage how much you will need to spread it, and go in short increments. Don't just go 1/2" past the desired dimension to start with, it might only spring back 3/8", leaving you 1/8" big. If the 4x4 section needs to be perpendicular to the lower section of the C, I would leave it off until you have adjusted the C. Get the C where you want it, then fit the 4x4 section to it. Again weld the 8" sides first, then the inside 4", then outside 4". I highly doubt that section will pull any noticeable amount, but if it does, welding the inside before the outside allows for using the bottle jack to further spread the C until that tube is again perpendicular to the lower frame. If you'd like, after welding both the 8" sides, you can grind out the remainder of the tacks on the corners, maybe gouge into each weld a little bit to make your tie-ins a little cleaner.
Reply:Would clamping the whole structure rigidly in place before welding help? Or will the whole thing not warp but the welds would crack when cooling if you do that?
Reply:Static- I have always locked the long flats on a restrained joint involving tubing because it was a necessary evil. It at least locked the original dimensions in. The inside/outside welds still changed the amount of locked up stress in the joint.That last half azzed cow tank thing I built was no different. Although I welded on the diagonals on the inside joints, I can guarantee you that if you cut any member of that weldment it would spring because of the locked up stress. It wants to fold into the direction of the inside fillet.With tubing, just what axis are you gonna try to correct. You have 3 axis.On the OP's project, he can at least pretty well control the dimensions of the c with respect to the opening. Allowing the short sides to pull in/out like they want to will at least stabilize that dimension. The real trick is to find out just how much they'll pull, and adjust for it.It's really pretty cool stuff.Last edited by farmersamm; 01-07-2009 at 09:08 PM.Reason: Speeeeling"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Originally Posted by TerrWould clamping the whole structure rigidly in place before welding help? Or will the whole thing not warp but the welds would crack when cooling if you do that?
Reply:That's why I really liked the fabricated column on the column replacement thread. It had a lot of distortion potential, and it was made really nice. That's neat stuff"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Real quick before I get outta here for supperLook at the base plate on the cell tower job. It had to be offset because it was gonna move. It will go where it wants to go. I don't give a damn what you do to it. You may restrict it, and maybe see less shrinkage results, but that thing has a lot of stored stress in it. It probably has an effect on the overall strength of the structure. That 's an engineering thing, I don't know crap about that."Any day above ground is a good day"http://www.farmersamm.com/
Reply:Originally Posted by Jim StabeI am going to be stick welding the frame shown below (4 x 8 x 1/4 tubing) and would like to keep it as flat as possible and keep the "C" from opening or closing as much as possible. I had planned to tack the elements together at the corners with a 1/8" gap and then weld the short sides first. I have a 3/4" steel table top that I can clamp the frame to for welding the long sides. Should I weld the long sides in short segments and flip it over after doing each short segment?Any advise will be greatly appreciated.Jim
Reply:my process would be to weld the inside verticals first and then tack a spreader bar to secure it. i would then weld the outside verticals. when all has been cleaned i would tackle the flats. i would clamp and weld all joints from inside to out on one side and then outside to in on the other.other than that i would use my magic straightener and beat the living poo out of it till it was square, level, straight, plumb, and flat.
Reply:Originally Posted by William McCormick JrIt has been my experience that the inside joints of the "U" or the "C" or the "L" will pull the most because they are the strongest area, structurally speaking. The outside of the jounts on the "U" or the "C" are the weakest because they lack the structural integrity of the inside joints. So I would tack it. Then weld the inside joint first, then weld out to the outside joint, and then weld the outside joint. I would actually do the inside joint and one side, flip it over, do the other side and then the outside of the joint for each connection. That should correct most of the warp. Remember the inside joint is pulling on a solid plate of steel that cannot give. The outside of the joint is pulling on a solid plate of steel that can give if the part is put under pressure. That is why we always weld to the outside of the joint professionally. If you have to bend it, it bends rather easily. However if you have hydraulic equipment like a porter pack around. It is very easy to open the "C" or the "U" with such a light and portable device. While crushing it closed with a press can work up a sweat. And send it across the shop. Ha-ha. But I would probably still weld out. Sincerely, William McCormick
Reply:Peen the tacks and welds every one of them, as soon as you finish them.Miller Thunderbolt 225Millermatic 130 XPLincoln HD 100 Forney C-5bt Arc welderPlasma Cutter Gianteach Cut40ACent Machinery Bandsaw Cent Machinery 16Speed Drill PressChicago Electric 130amp tig/90 ArcHobart 190 Mig spoolgun ready
Reply:This may be a stupid question but cant you tack a piece of tube to the top (open end) and then weld it however you want and when finished cut the tacks???
Reply:Originally Posted by down19992000This may be a stupid question but cant you tack a piece of tube to the top (open end) and then weld it however you want and when finished cut the tacks???
Reply:Gaps will increase your shrinkage as will any increase of weld bead size. It is something to keep in mind. Tack weld at about four locations on each connection, checking for any movement. A narrow cutting disc on a small grinder will allow you to cut any tack that has moved the frame. Keep in mind that the joint can be hinged on one or two tacks and then re-tacked. Brace across the opening of the C with a larger tube or angle. Guessing at the size of the tube I would use 3 by 3 angle bracing. I would put another two braces completely across the frame from one side to the other between the joints, Tack the braces on one edge of the angle ( heel is best) so that they can be snapped off later. Those heavy angles will limit twisting out of plane. One angle would have four tack welds an inch long, two on each tube it crosses over.The bracing and tacks should be good enough that you could drop the frame on the floor and not have it move.Now start your welding alternating sides and edges moving around to even out stresses and heat.Let the unit cool for several hours. Overnight is better. Snap off the angle braces and see what you have.Sure as God made little green apples it will have moved in some way. A simple C frame like that is not hard to shrink open or closed. Shrinking it when out of plane is a bit more difficult but very doable.
Reply:Originally Posted by lotechman...Sure as God made little green apples it will have moved in some way. A simple C frame like that is not hard to shrink open or closed. Shrinking it when out of plane is a bit more difficult but very doable.Originally Posted by down19992000This may be a stupid question but cant you tack a piece of tube to the top (open end) and then weld it however you want and when finished cut the tacks???
Reply:If your cuts are really accurate - start with the middle piece and tack then weld it on the inside. the welds will pull it into square.You will need extra long welding rods.Last edited by Magnetic Mechanic; 01-08-2009 at 09:28 PM.Reason: forgot last sentenceA butterfly without wings, is just an ugly bug
Reply:Originally Posted by Jim StabeMy primary concern is maintain the plane......
Reply:Thanks to everyone for their advise. I welded it up and it stayed very flat and I was able to control the closing up of the "C" to within 1/16". I did it in 3 stages. I welded the bottom arm and the corner piece together, then the top arm and the corner piece, then wleded each assembly to the backbone piece. This let me make adjustments to the setup after I saw how the angles were going to behave. I tacked each corner with a substantial tack then welded the inside 4" joint. The 8" sides were next fron the inside to the outside and I finished with the outside 4" joint.I still have to make the vertical arm (the cardboard pattern) and weld it in. It will be a pie cut piece of the 4 x 8 tubine. I wanted to leave the top piece where the adjuster will be and the lower arm for last so I could control their alignment closely. Again, thanks for all your help - JimCut an MGB and widened 11" C4 Corvette suspension and LT1 Chevrolet power & 6 spd. Pictures here:Part 1http://forum.britishv8.org/read.php?13,7581Part 2http://forum.britishv8.org/read.php?13,22422
Reply:Originally Posted by Magnetic MechanicIf your cuts are really accurate - start with the middle piece and tack then weld it on the inside. the welds will pull it into square.You will need extra long welding rods.
Reply:Originally Posted by DmaxerUse a true, solid welding table. Clamp (or tack) the pieces down and ensure there are no gaps at the joints that can shrink and induce torsion in the workpiece. Tack carefully and completely according to a plan that will minimize warpage, turning the piece and re-clamping as necessary. Weld in the correct sequence and minimize localized heat application to further minimize warpage. If you don't know the right sequences, get a book that covers this if you haven't gathered enough from the preceding posts.
Reply:Originally Posted by Jim StabeThanks to everyone for their advise. I welded it up and it stayed very flat and I was able to control the closing up of the "C" to within 1/16". I did it in 3 stages. I welded the bottom arm and the corner piece together, then the top arm and the corner piece, then wleded each assembly to the backbone piece. This let me make adjustments to the setup after I saw how the angles were going to behave. I tacked each corner with a substantial tack then welded the inside 4" joint. The 8" sides were next fron the inside to the outside and I finished with the outside 4" joint.I still have to make the vertical arm (the cardboard pattern) and weld it in. It will be a pie cut piece of the 4 x 8 tubine. I wanted to leave the top piece where the adjuster will be and the lower arm for last so I could control their alignment closely. Again, thanks for all your help - Jim
Reply:Originally Posted by William McCormick JrThey look tough. If a joint does open a bit, you can put a pipe clamp across the "C". And do a pass to the inside of the joint under pressure. It will move a lot while under pressure. And visa versa you can put pressure outwards with a jack, with just a couple hundred pounds of force, and do a pass to the outside. It will just open right up. I have found that stick and MIG pull less then TIG. It looks great. Good luck with it. What is it? Sincerely, William McCormick
Reply:The old E-wheel was too flexible in which direction(s)?If the wheels/anvils were chattering or dancing around, it could have been the relatively skinny posts that directly hold the wheels/anvils themselves. If you beef that area up, the wheels/anvils will be held more stiffly although tight-quarters wheeling may get interfered with.Also, the back of the frame has that triangular bar 'stiffener' set-up (like what is usually on the top beam of an engine hoist/cherry-picker/shop-crane). Which would help stiffen things better if the back of the frame were in tension instead of in compression, which is how the frame will actually get loaded when you use the wheel. Maybe 'box' out the back of the frame with 1/8 - 1/4 inch thick gusset 'skins' and turn the existing tube frame into a BIGGER tube frame. That would stiffen things up.Oh, and don't use the band saw to open a can of lacquer thinner. The best laid schemes ... Gang oft agley ...
Reply:I agree with moonrise. The design of your stiffening bridgework on the back of the machine is on the wrong side. Simply turning the bracing to the opposing side would more than likely fix a lot of flimsiness.Esab Migmaster 250Lincoln SA 200Lincoln Ranger 8Smith Oxy Fuel setupEverlast PowerPlasma 80Everlast Power iMIG 160Everlast Power iMIG 205 Everlast Power iMIG 140EEverlast PowerARC 300Everlast PowerARC 140STEverlast PowerTIG 255EXT
Reply:All the 2" sq stiffening is coming off. The 3 x 5 vertical post will remain just to support the new frame and only up to the point where it goes off at a 45* to meet the top arm. All the stiffness of the new frame comes from the section of the tubing, maybe a little from the 3 x 5 that will be stiched to the back. Before it was too weak in all directions, vertical and horizontal where the wheel axles deflect out of line with each other. Calculations from people who build these for a living indicate that this will be about 3x stiffer in the vertical and 4-5x in the horizontal. I'll let you know how it work out.JimCut an MGB and widened 11" C4 Corvette suspension and LT1 Chevrolet power & 6 spd. Pictures here:Part 1http://forum.britishv8.org/read.php?13,7581Part 2http://forum.britishv8.org/read.php?13,22422
Reply:Originally Posted by Jim StabeGood tips on making final adjustments after it is welded. It is the frame for an English wheel used for sheet metal forming. This is my existing one that is too flexible.This is how the "C" will be oriented on the new one with the addition of the lower arm (cardboard pattern in my previous post.Thanks againJim
Reply:Mr. McCormick- The flange in the video.I was wondering if the extra meat also added ridgity as far as the "c" goes. I don't know how to explain it, but it seems that adding metal to something, and adding it where it takes the force in stress, as opposed to being in compression seems to add to the overall strength much more than increasing the overall mass.I mean, like strongbacks. You always see them on the stress side of the beam, very seldom on the compression side. I think metal has a greater tendancy to buckle under load than it does to break under stress.I'm not sure if this is right"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Originally Posted by Jim StabeAll the 2" sq stiffening is coming off. The 3 x 5 vertical post will remain just to support the new frame and only up to the point where it goes off at a 45* to meet the top arm. All the stiffness of the new frame comes from the section of the tubing, maybe a little from the 3 x 5 that will be stiched to the back. Before it was too weak in all directions, vertical and horizontal where the wheel axles deflect out of line with each other. Calculations from people who build these for a living indicate that this will be about 3x stiffer in the vertical and 4-5x in the horizontal. I'll let you know how it work out.Jim
Reply:Originally Posted by farmersammMr. McCormick- The flange in the video.I was wondering if the extra meat also added ridgity as far as the "c" goes. I don't know how to explain it, but it seems that adding metal to something, and adding it where it takes the force in stress, as opposed to being in compression seems to add to the overall strength much more than increasing the overall mass.I mean, like strongbacks. You always see them on the stress side of the beam, very seldom on the compression side. I think metal has a greater tendancy to buckle under load than it does to break under stress.I'm not sure if this is right
Reply:The strongbacks also have a purpose other then just strength. They are designed to keep something from leaking out. The reason for the large flat plate. But they are under both kinds of stress simultaneously. Depending one where you are compared to the bracing. Sincerely, William McCormick
Reply:Sorry to be such a pain in the butt.That makes sense. Ideally you would close the throat to the minimum required to fit something in it. Not possible for the tool to do what it's supposed to do.Is the thicker piece of plate on top of the tubing much stronger in relation to the tubing itself? This relates to the tension thing I'm trying to fully understand.By adding the plate to the top of the tubing, are you adding a tensioner, or are you adding just another 1/2 inch to the thickness of the beam. I'm looking at the inside of the "c" as resisting a force going to the outside of the "c" placing the added flange under tension.Thanks for your patience"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Last response was in response to post 40I wish to hell this was in real time. I'd really like to understand this stuff"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Originally Posted by farmersammLast response was in response to post 40I wish to hell this was in real time. I'd really like to understand this stuff
Reply:Originally Posted by farmersammSorry to be such a pain in the butt.That makes sense. Ideally you would close the throat to the minimum required to fit something in it. Not possible for the tool to do what it's supposed to do.Is the thicker piece of plate on top of the tubing much stronger in relation to the tubing itself? This relates to the tension thing I'm trying to fully understand.By adding the plate to the top of the tubing, are you adding a tensioner, or are you adding just another 1/2 inch to the thickness of the beam. I'm looking at the inside of the "c" as resisting a force going to the outside of the "c" placing the added flange under tension.Thanks for your patience
Reply:Sam it is great to have someone to talk to that is interested in structure. Exercise for the mind. I know I need it. I just barely caught some major linguistic errors, as I was posting to you. I needed the exercise. I mean to say one thing, and I write down that one thing. Then I go back and re-read it, and I say "wow, I wrote that"? Ha-ha. It is the language, we are using it very poorly by habit. Years ago my old friend Bart who owned a local steel company, would sit around with me for two or three hours every time we got together. He supplied the steel for a lot of buildings in Manhattan. Wow, everyone should have heard what he had to say. The world would be a safer place. He was getting on in years and did not bother to argue with the new architects as much, they would make his work difficult for him. So he just gave them what they ordered with a warning. He was a tough boy though. He told me that with the current structural steel that you need an inch of height to a foot of run or span of structural "I" beam. For commercial flooring loads. And I always held to that when I picked the beam. You know I never had a beam deflect. When ever I installed someone else's beam, they were always undersized, I saw deflection as much as a 1/2" over 16 feet. You just know it is wrong once you have done one that is right. Bart told me that real steel weighs in at 27 pounds a square. One inch high and twelve by twelve inches square. The funny thing was that is how he charged me for the stuff that weighs almost 41 pounds a square. He was a funny guy. And a good friend. If you have a project or subject I would love to discuss it. Sincerely, William McCormick
Reply:william,a month age i passed on some prints due to a disagreement. the prints said that the floor was to have 6 inch i beams 2 foot on centers that spanned 16 foot. i insisted that there must be a misprint. the guy was too arrogant and didn't want to go back to double check. there was no midspan support for the floor. i don't know if it was right or wrong, but i simply wanted to double check the print due to i seemed a little wrong. if he had said, "sure, i'll put a call in.", then i would probably be doing that job, but i am not.now if i apply your formula the prints were well out side what was needed. what should it have been??
Reply:steel is around 500 pounds / cubic foot. 1 inch x 12 inch x 12 inch = 500/12= 41.66 pounds.bart is wrong about the 27 .
Reply:Originally Posted by Scott Youngwilliam,a month age i passed on some prints due to a disagreement. the prints said that the floor was to have 6 inch i beams 2 foot on centers that spanned 16 foot. i insisted that there must be a misprint. the guy was too arrogant and didn't want to go back to double check. there was no midspan support for the floor. i don't know if it was right or wrong, but i simply wanted to double check the print due to i seemed a little wrong. if he had said, "sure, i'll put a call in.", then i would probably be doing that job, but i am not.now if i apply your formula the prints were well out side what was needed. what should it have been??
Reply:Originally Posted by weldbeadsteel is around 500 pounds / cubic foot. 1 inch x 12 inch x 12 inch = 500/12= 41.66 pounds.bart is wrong about the 27 . |
|
发表于 2021-9-1 00:47:47