Frame jig

Txasflood · 11-17-2012, 05:54 PM

Hey Im sure this topic has been talked about quite a bit. I have a different question/angle on it though.. I know the factory dimensional tolerances are pretty liberal and there seems to be conflicting opinions regarding Liskey vs shop manual numbers. My question is instead of building a jig according to numbers from either of these, what if my jig is built to existing points on the car given that it is leveled and squared? My car is straight just starting to rust. I would like to eliminate all the rust by replacing as much as I can with Dynacorn parts. I would like to do all four frame rails, the floor, most if not all of the firewall and possibly torque boxes depending on how bad they look.

Basically I built a base with 8 levelers which will give me a level datum plane to begin with. What I am thinking of doing is supporting the car by common mounting places like rear leaf spring points, front suspension points, door hinge and front frame rail holes. From there fabbing up a bunch of locating brackets from one frame rail to another basically to position the new complete frame rail replacements as I change them one at a time. Below are a couple of pics of what I made yesterday. I would love some feedback from those of you who have messed with jigs. Thanks!

shelbyshelby · 11-17-2012, 06:20 PM

I would think you would be good to go provided the car hasn't been in an accident or the rust hasn't compromised the integrity. Makes me wonder about that because of the parts you are already named. Shows us pics of the rust if its accessible. Now that I'm thinking about it, the shock towers is about the only area that tends to move as they get old. Maybe the area where the roof meets the quarter panel is an area that gets ripped from heavy race use.

rdlagray · 11-17-2012, 07:06 PM

I built mine basically using the measurements from the shop manual. But I did change the measurement on the rear of the leaf spring because it would not bolt up to my car unless I did. My car was straight and body panel fit good before and after I got it off the jig. I did alter all the measurements from the shop manual but I altered them all the same except the last one I mentioned above. I think you will be fine I would just make sure the fenders,doors hood and trunk are all in place when you make the jig.
Nice looking rotisseri. Did you make it? That gives me a good idea for the balancing system which I never did get made for mine.

Txasflood · 11-17-2012, 07:18 PM

I appreciate the response! Here are a few pics of what I got goin on.

Txasflood · 11-17-2012, 07:23 PM

rdlagray, Thanks for the info. I cant believe I didnt even think about having the fenders/hood etc on before making the jig. Makes sense and could have been a real bed mistake! I bought the rotisserie on ebay for just under a grand.

slim · 11-17-2012, 07:31 PM

So how do you decide on correct dimensions?

Txasflood · 11-17-2012, 07:41 PM

What do you mean Slim? I have checked them compared to the repair manual numbers and they seem to be in line with the dimensions given. Im basing the conclusion that my cars numbers now are as good as they ever were on the fact that it drove straight, the body gaps were great and there is no evidence of accident damage.

xcelr8 · 11-19-2012, 08:18 AM

Quote:

Originally Posted by Txasflood

....instead of building a jig according to numbers from either of these, what if my jig is built to existing points on the car given that it is leveled and squared? My car is straight just starting to rust. .

Exactly what I did with mine. I put the new inner fender/frame/tower assembly in position the other day and it seems to line up really well. Haven't gotten as far as fender alignment yet *fingers crossed* but the way I did the jig seemed to make more sense.

rusty428cj · 11-19-2012, 08:49 AM

We will be doing something like this but on wheels so it can be moved. I would also tack weld a couple of supports to the rockers. Another good place would be where the crossmember bolts to the frame under the engine and the front bumper bracket holes.

ScottsGT · 11-19-2012, 08:55 AM

I've often thought that a proven jig like this can also be used to build a new body out of replacement panels too. Sounds like a great idea.
Do yourself a favor though and don't make the same mistake I did. When aligning fenders during the bodywork phase, don't just use one or two bolts on the ends and call it a fit. use bolts at ALL locations to fit a fender.
I had the hardest time aligning mine due to this. Even after installing with the two or three bolts tightened down, all the others started pulling things in directions I didn't see coming.

Txasflood · 11-20-2012, 08:49 PM

I really appreciate the positive input everyone thanks for the help!

xcelr8- Did you have the full inner fender/frame rail assembly from Dynacorn? How did it seem to mate up with the firewall?

rusty428cj- I thought about that but wasnt sure. Do you think it would be better than attaching at the door hinge locations?

Scottsgt- Thanks for the tip! Body work seems so far away!!

Thanks again everyone for your info. VMF is awesome! I have been a part of a couple other forums and its always a bunch of "tough guys" that just want to dump on you for asking questions and insult you for not knowing what they do. Im loving VMF and cant imagine trying to start my resto without the input from people like you all helping me along!

dnh4976 · 11-21-2012, 02:24 AM

In my opinion, the only time a frame jig is truly beneficial is when you are doing several cars of the same make. You'll spend more time building and setting up the jig than it will take to level car for the datum plane and take the measurements. Ultimately, the jig will only be as precise as the measurements you take anyhow. I've done it both ways.

xcelr8 · 11-21-2012, 08:25 AM

Quote:

Originally Posted by Txasflood

I really appreciate the positive input everyone thanks for the help!

xcelr8- Did you have the full inner fender/frame rail assembly from Dynacorn? How did it seem to mate up with the firewall?

No prob! Yup that's the one. I got it for $350 shipped via a guy on Ebay who bought out a failed Mustang parts shop. I wont be as lucky $ wise when I buy the passenger side. There really isn't a lot of people who have used the entire assembly like me. I've been looking and asking since I got the car in Feb and only two people have done it.

I haven't set a fender on it yet, but everything else lines up really well. A 2-3" section of the rear apron that follows the firewall contour sits a tad further from the firewall for my liking. I'll probably cut that out and add metal to bring it closer. Frame rail to toe board fits perfect and cross member/sway bar mounts are correct.

I originally thought about doing just the rail, but after seeing all those freaking spot welds I went another direction. Scared the crap out of me to cut the front end off at first. Lost sleep over this project the first two months I had the car. Now I switch off the brain and get in a zone when working on her. This forum and it's members put me at ease about what I was doing.

rusty428cj · 11-21-2012, 08:28 AM

Quote:

Originally Posted by Txasflood

I really appreciate the positive input everyone thanks for the help!

xcelr8- Did you have the full inner fender/frame rail assembly from Dynacorn? How did it seem to mate up with the firewall?

rusty428cj- I thought about that but wasnt sure. Do you think it would be better than attaching at the door hinge locations?

Scottsgt- Thanks for the tip! Body work seems so far away!!

Thanks again everyone for your info. VMF is awesome! I have been a part of a couple other forums and its always a bunch of "tough guys" that just want to dump on you for asking questions and insult you for not knowing what they do. Im loving VMF and cant imagine trying to start my resto without the input from people like you all helping me along!

I would want to line up the doors and fenders while it is on the cart.

Txasflood · 11-21-2012, 05:26 PM

Quote:

Originally Posted by xcelr8

No prob! Yup that's the one. I got it for $350 shipped via a guy on Ebay

Scared the crap out of me to cut the front end off at first. Lost sleep over this project the first two months I had the car. Now I switch off the brain and get in a zone when working on her. This forum and it's members put me at ease about what I was doing.

Nice! It must have scared the crap out of him so much he changed his mind! I know what you mean about losing sleep, I find myself sitting in my old rocking chair out in the garage drinking beer and looking at my car...Trying to make a game plan for attack!!