At what point would you need a frame jig?

[jimynick]

May one enquire what it is that you're planning to do to this car, that you feel a jig is required? 

[gzig5]

I have a jig.  I have not used it yet but have one.
I can get some pictures if someone needs a pic of a home made jig. 

It has been used on several known restorations.

Yes, pics please.  I'm going to have to repair passenger side rocker and the door jamb pillar this winter.  I feel that in order to do that correctly I need to drop the engine/trans/K-member and get the body on a jig of some sort and brace it.  I'm interested in what size material is required to give the needed stiffness, depending on the design, of course.

[cuda hunter]

Ok.  I will get a pic sometime soon. 

[70 Challenger Lover]

I have a car that is so badly rusted it probably should have been crushed. On the front end, I set the shell on long thick metal U channels resting on stands. Once the car was shimmed out perfectly, I found it very helpful to make all frame measurements. Once the front end was done, including rails, shock towers, upper and lower cowl, etc,  I put it all together and everything lined up super nice. So the jury rig method did work out just fine for me.

I was going to use the same method on the back half for quarters, trunk, etc. but I took a detour to finish my RT so I could get it out of my way. Now that I am about to have lots of room, I have decided to build my own rack for the back as well as for future metal restoration needs. I probably wouldn't bother if it was just this one car but I do enjoy the metal work and likely will build cars well into my retirement years so the rack will probably come in super handy for me.

I wasn't able to open the AMD site so not sure what they use. I found a nice rack online and using it as a basic guide, I have designed a number of changes into it to provide for lots of adjustability and for breakdown and storage. It would be heavy enough to use it for pulls if I wanted but I doubt I'd do that unless it was just minor pulls. What I really want is just a rock solid rack I can set the shell on and then use as a base for precise frame measurements as I put new pieces back on.

This is the rack I found online. I just started building some of the little pieces the other day and I'll make a full post once it's complete and has a shell on it. Basically, I like this one but I want to add side to side adjustability as well as front to back adjustability on all frame resting points. Mine will have heavy duty casters but I am also going to add threaded rods I can screw down to lift the wheels off the ground and of course to make it perfectly level.

[cuda hunter]

Here is what I have.   It's at the sand blasting shop right now. 

[gzig5]

Wow, that is pretty simple.  But I guess as long as the load is supported directly under the uprights like that, it won't flex.  Looks like it is picking up on the two X locations and the top of the over axle bend?

Where would I be able to support it if I'm putting in one of those Dynacorn sub assemblies that go from the rear seat pan to the tail panel?
https://www.rosevillemoparts.com/product/trunk_-underseat-floor-and-rear-frame-assembly-70-74-challenger/

[cuda hunter]

Good question.  I'm going to have to figure that out as I'm replacing the rear section. 
I'm assuming that the two X locations will support the car since there won't be anything else back there until I put the pan in place on the cups. 

[JS29]

Most frame and unibody shops use the pinch weld area on the bottom of the rocker panel. They make clamps to secure it. I have them that use pipes and jack stands made for that per pus 

[Brads70]

Most frame and unibody shops use the pinch weld area on the bottom of the rocker panel. They make clamps to secure it. I have them that use pipes and jack stands made for that per pus 

That's what we used on Mikes cars ( pinch weld area) It clamps very solid to the pinch weld area , then again to the table.

[gzig5]

Most frame and unibody shops use the pinch weld area on the bottom of the rocker panel. They make clamps to secure it. I have them that use pipes and jack stands made for that per pus 

Thanks for verifying.  After I entered the question, the pinch weld under the rocker became obvious. I think I might need something a little longer than Cuda Hunter's?
I found a pair of 4" x 96" long pallet rack beams that are rated for 4500+lbs that would make a nice starting point for the Jig. 
https://milwaukee.craigslist.org/tls/d/hartford-pair-of-96-pallet-racking/6985009982.html

Think it would need to be longer than 96" to be able to support the front rails at the K frame?  It can't be any longer than the car and fit in the space I'm working.  96" is 8 feet (for those of you using the metric system  ) and that seems short.  Car has about a 10' wheelbase and I think I'd want it a foot past on each end so I can get to the K-frame area, so 12' overall?  I can always add extensions.  The yellow one shown a few back is too big, but I can model off of it.

Don't want to sidetrack this thread too much.  If I need to start a separate discussion on jig design, let me know.

[cuda hunter]

Pretty sure mine is just under ten foot.

[JS29]

 @gzig5  @cuda hunter Look at the picture of the camps from brads post. When making a pull it's held at four points. You are only going to support your car, those same four points are all that is needed. I don't have a dedicated bench, I have four clamps two heavy pipes and heavy jack stands that have islets or holes that the pipe slides through.