View Full Version : How do you fix this crooked thing?

10-26-2009, 01:02 AM
Ok I mess this up. How do I fix this crooked thing? Do I have to start over from scratch again?

10-26-2009, 01:12 AM
how crocked is it and where ?

is it from the pieces being miss aligned or did the metal pull from the heat of the welds ?

10-26-2009, 02:07 AM
If its twisted maybe careful application of steel under the low sides and a couple of vehicles carefully applied to the high sides.

10-26-2009, 05:26 AM
This so called to be my one of my X axs is mostly twisted from the heat of the welds. and a few misalignment also.
KIMFAB I don't really understand your instruction.

10-26-2009, 06:06 AM
This book helped me out a ton years ago. Now that I have a better idea how the heat affects things, I take measures to keep it from distorting in the first place.


10-26-2009, 06:16 AM
There are two main issues that need to be addressed,
1. To straighten it we need to know where and how much distortion.
2. What is the objective, ( what were you hoping for)

I am thinking that the easiest way would be to grind the top mounting ( given the holes are in line) Also need a little x bracing.

The detail on how you intend to separate the these rails ( Is this a gantry or a long axis mounting ?)
so many options, not enough info. Have you got some drawings??


10-26-2009, 09:08 AM
Ok I mess this up. How do I fix this crooked thing? Do I have to start over from scratch again?

Proper application of heat (in the right place) can warp it back.

10-26-2009, 09:27 AM
I think what KIMFAB was saying is lay it down on it's side and there will be two opposite corners touching the ground and the other two corners will be the high corners. Put some blocks under the low corners because with you straighten it, it will spring back a bit so you have to compensate for that. then put a ramp or something so you can get a vehicle or some other weighty object on one of the high corners and repeat on the other high corner with another vehicle to straighten.

10-26-2009, 03:24 PM
Know anybody that works for an auto body shop? They often have frame straightening equipment that will make short work of it.

10-26-2009, 06:32 PM
Cschmidt got it. this will work to flatten it. If it is bent another way you will have to use a porta-power to bring it square

10-26-2009, 08:11 PM
read the book or look up the info on using heat forces to straighten metal things- its a very effective method but not many know it well. proper application of heat and selective cooling can straighten that item. its not simple since the thing is a multiple box beam structure but if you pull it a bit at each frame, then you will be able to accumulate enough to get it plumb. patience is necessary, probably will be a few errors in trial unless yo u have done this before. at a shop where I worked, we adjusted the articulating joints for 20 foot manlift sections doing this, works great when you do it right. learn it first and test a small section to see if you have it right, then go at it. hose water is handy for fast cooling but it can stress tight welds, it moves the metal FAST.

otherwise, if you can put it under a 4-corner chained-down restraint like a frame jig then you can take a 6-10 ton hydraulic jack under each of four points and push until its straight. learn how much push it takes just to take the normal flex up and watch the rebound losses, after a few pushes you will see how much to go at each stage. may need to move it to get the straightness along the entire length. you can easily break welds this way also, plan to re-do a few if they crack. reweld them under tension to keep the frame straight and then some, then release. their slight contraction will draw a small amount.

otherwise #2, figure out where to locate them to pull it straight, heat up about 6 pieces of sturdy steel pipe or hefty rebar, weld them with gussets at ends in place while they are warm, then when they cool they will draw the frame with their contraction. you can use the heat/cool method on them to adjust their tension also.

10-27-2009, 03:35 AM
I haven't done anything to make them straight yet as I'm not sure of what to do. Here are just the 2 photos showing 2 of the twisted Y? axis (1 is twisted severely).

10-27-2009, 03:31 PM
I'm afraid you have lost me on this one. I don't see any appreciable twist in your pics. Is your first rectangle a parallelogram or is it square and not flat?
Also if these pieces are not straight welding more stuff on without straightening the sub-assemblies will just make it worse and harder to fix.
Take some pics with a square or one that sights across referencing one side to the other for a better reference.