Dealing with a warped Frame

[kevingb]

Ok.. Mistake #1

I had a perfectly square frame. My back got sore so I decided to lift the frame up on some saw horse to do some small final touchs with my stabilizers. Going great!!! I layed out the hangers and spot welded in place.

Everyone was gone, no help to get back on the ground, and I did the biggest mistake. I ran the final welds with the frame hanging in a negative position causing a convex warp on both sides of the outside rails. Interesting thing both of them were exactly with the same amount of drop.



If the frame was concave I wouldnt be as concerned but with convex, thinking it will put some undue strain of the wall to floor joints.

Need some advice please on which method you would go with?

I can cut a notch and bending back to normal and running a bead to close the gap. I really thinking this is the best way. The wire has higher tensile strength than the metal itself.

The other option is to heat up the tubing and bend back into place. This is going to really mess with tempering, if sq tubing really tempered.

Thanks for all input

[Steve_Cox]

Frame warp has affected many of us to a varying degree. Mine was on it's way to being a parallelogram after tacking it up, got it in square with a come-a-long and a couple of C-clamps on the corners while I finished welding. Miriam C. had a problem with one corner being a much different height, I think it was bags of sand she used to straighten it out while it was suspended. However you do it, nice thing is you only have to get it close. the Floor, frame and side walls will keep it flat as you assemble your teardrop which some here consider a torsion box. Please let us know how you proceed and good luck.

[doug hodder]

So how much did it bow? I have that problem all the time...and I don't do much of anything about it. Any time you throw heat into spring hangers from welding, doesn't matter which way it's sitting, it's gonna shrink/pull on the welded side. It's just something that a garage builder has to deal with.

I don't have an "official" jig to do my welding in and it's done on the floor. I try to minimize it by only doing 1 short pass, then on to the other rail and let the first one cool before I heat it up again. On the really thin material frames, I've built in 16ga., I will back it up with another piece and clamp them together, but it still pulls some. Others may disagree, but that's been my experience and how I deal with it. Doug

[aggie79]

The frame I had build had a similar curve - I guess it happened when he welded on the brackets for the torsion axle. The frame was out about 1/4" camber to it. It took some effort, but I was able to take the bend out with a hydraulic jack.

[kevingb]

From the shackle to the back of the trailer is about 1/4" drop and from the front hanger to the front was about 3/4" to 1" drop.

Cutting or heating might not be the best first attempt to fix.

Thanks for the alternatives, going to sleep on it.

[Wolfgang92025]

I had the same problem. Used a long chain, and strung it like a bow with a bottle jack in the middle. Pump up the jack till the rail was about a couple of inches past center. That took care of most of the bow.

Wolfgang

[eamarquardt]

Your frame was bent by heat and can be straightened by heat. I looked in your album and it appears you're using 2X2 tubing. During welding you deposit molten metal. As it cools it shrinks and pulls. Just as heat bent it, heat can straighten it. If you can get an oxy/act torch put a fairly large tip on it. Depending on the thickness of your tubing a propane or map gas torch might work. Given your frame is bent right at the spring hangers (as that's where you bent it) heat the area opposite the hanger (on the convex side) and use water or a water soaked rag to cool it right after heating so you can see how much you've straightened it. Experiment a bit and with a little practice I'm sure you can get it pretty close. When you heat the metal it expands but it also softens and pushes in on itself. When it cools it shrinks where heated, pulls in on itself, and will pull/bend the tubing.

You can also phyiscally bend it as others have suggested. I'd recommend not cutting a section out and reweldiing it as you'll have shrinking issues with the weld the tubing may not be as strong after cutting and welding.

I've used heat and jacks to strighten things in the past with good success. Just sneak up on it a bit at a time.

I wouldn't lose any sleep over this.

Hope this helps.

Cheers,

Gus

[G-force]

Weld a couple of beads on the top side of the tube right over your other welds. It will pull it back. Then grind them flush. Sounds too easy but it works.

[Larwyn]

Weld a couple of beads on the top side of the tube right over your other welds. It will pull it back. Then grind them flush. Sounds too easy but it works.

Quick, easy, effective, and requires no additional equipment over what was used to weld up the frame.

I generally use a combination of heat, clamps, hydraulics, and "precision" impact instruments (otherwise known as BFH). The hammer might not do much for the frame in your particular situation but it's use is still good for the soul.

[fromeo]

Weld a couple of beads on the top side of the tube right over your other welds. It will pull it back. Then grind them flush. Sounds too easy but it works.

x3. This will do ya.

- Frank

[kevingb]

got it fixed... I just took my cutting torch and scrapped the whole thing...SIKE!

I was going to do the run a few beads, but grabbed the torch first. I heated about 1" wide across the top and little down the side. BADABING! It worked. Actually didnt look like it made a difference until it cooled off.

I'm so use to working with thicker steel, thanks for catching me before going too extreme. Heck, one day in the Texas sun prob would have straighten it right up.

actual measurements was 3/8" offset in the back and 1-1/4" in the front



Thanks again.

[eamarquardt]

got it fixed... I just took my cutting torch and scrapped the whole thing...SIKE!

I was going to do the run a few beads, but grabbed the torch first. I heated about 1" wide across the top and little down the side. BADABING! It worked. Actually didnt look like it made a difference until it cooled off.

I'm so use to working with thicker steel, thanks for catching me before going too extreme. Heck, one day in the Texas sun prob would have straighten it right up.

actual measurements was 3/8" offset in the back and 1-1/4" in the front



Thanks again.

No grinding required! Actually the heating bends it more in the wrong direction initially and the "correction" takes place when it cools.

Glad it worked out.

Cheers,

Gus

[Larwyn]