'70 Vert - waited long enough...

[Challenger RTA]

The starting point is were I gave the measurements 0. I see you have it on a jig. You not building the car from scratch. You have to find where your at and meet the existing. The front and rear laterals have to be check for square.

 

[Cuda416]

The lasers that are other there are more than likely good enough for what you want to do. Your not going 100' to 400' on any kind of control line. Those lasers have an X and Y axis that has to be checked. They can be field calibrated. Get any laser level (Harbor Freight) and the bubble will be off a little. For most there is no calibration to adjust. There not built like a machinist level. when you set up the laser check the start and end point. Pay no attention to the bubble. If you do turn the level 180 degrees and check. That will show how much the level is off. So minute it wont matter.
Plain and simple a string line is a straight line. All depends who it's set up and used.
A Harbor Freight level is good enough for what if for. I think about 50' you see line separation. Meaning you will see dots and dashes.

Yup, been looking at them for a while so I'm familiar with how to test them and they "can" be calibrated but it will void the warranty since you have to crack them open and adjust the pendulum weights.

The bubble I'm talking about is the old traditional 4 or 8 foot level, not the one on top of some laser levels. As an aside, I bought a harbor freight LL years ago and wasn't impressed which is why I'm asking about other units here. Looks like for the most part they've all seen some improvements so I'm not worried about the newer ones anymore. That old one would sometimes not even find it's level after being bumped.

I'm good with less than 1/8 error. I can objectively measure that and compensate if it keeps me up at night, which it won't.

At the end of the day, the more accurate I am at this stage, the more accurate things will be when the measured point is 6 or 8 feet from the stable reference. Distance magnifies the error a lot. 1/8 at the door top could be 1/2" height difference of the shackle. That's easy to show using a simple "L" drawing using the outside end of the short end of the "L" as a pivot and the intersection as the door jam top. Clearly you need to rotate the "L" 90 deg for it to fit the model.

Thanks again.

 

[Cuda416]

In a sense no. The work is of the 0 body line or the datum line. And yes it helps a lot for less error if the jig or car is level. Measure twice cut once.

Fair statement, I am using "level" as a reference to the datum line.

 

[Cuda416]

The starting point is were I gave the measurements 0. I see you have it on a jig. You not building the car from scratch. You have to find where your at and meet the existing. The front and rear laterals have to be check for square. Then, I'm looking back to see what you have set up.

This is where I'm going back to in my process. I need to establish a good, known baseline from which to measure from.

 

[Cuda416]

By the way @Challenger RTA , the measurements you provided were and will continue to be of great value to me, so thanks again for those.

 

[Challenger RTA]

Distance magnifies the error a lot.

That is correct. The distance your working with is infinitesimal. At times I worked with PennDOT survey team. I think there are 3 teams in the state. We would move a bench mark 10-12 miles. And the same for a company when building a bridge or road. When the cars were built there can be and is a lot of times 1/4" error. The end result is what matters.

 

[Cuda416]

That is correct. The distance your working with is infinitesimal. At times I worked with PennDOT survey team. I think there are 3 teams in the state. We would move a bench mark 10-12 miles. And the same for a company when building a bridge or road. When the cars were built there can be and is a lot of times 1/4" error. The end result is what matters.

Yes again we agree. I'm not using a transit with black widow silk cross hairs and I realize that. I'm stacking the deck in my favor. The less error I have now, the less I need to "fix" later.

 

[Challenger RTA]

Back to what I was getting at. The car was built with the jig holes. Do you think the workers were placing the part on the jig with precision care. There was room to drop and go. That's where the error comes in. 1/8" here and 1/8" there and the next part didn't fit it just got slammed on.

Being on a jig if the jig is set right you good.
You need to me check the center section for square first. then pull all the measurements that can be done with a tape. If you don't have the K frame on put it on. That is where it matters. Check the K frame measurements. the one that mater the most is E. Lower control arm measurements. That's why I sent a blank sheet.
I would pay no attention to the bubble use it as a reference to get you close. What matters is where the laser is hitting when set up. Beginning target and the last one. I think the beam is about 3/8" higher then the base of the level.

 

[Cuda416]

You not building the car from scratch.

Pretty darn close actually. I'd estimate 80% of the sheet metal is being replaced, maybe more.

F/R frame rails
Floor/trunk
1/4's
Tail panel
all three crossmembers
forewall/upper cowl
hinge and inner cowl panels
Inner/Outer rockers
entire front clip
Outer wheel wells

and all the misc parts in between.


The car is a basket case and I'm stubborn as hell so I'm doing things as methodically as I can even if it means taking three steps back to move forward one.

 

[Challenger RTA]

As I was saying. You have to meet the existing. Having it on the jig set up correct. It's pretty much fool proof. You just have to see where it's at. Get the platform done first and build up. There are no and I mean no upper body measurements. Only the one's you make or I gave.

 

[Cuda416]

Back to what I was getting at. The car was built with the jig holes. Do you think the workers were placing the part on the jig with precision care. There was room to drop and go. That's where the error comes in. 1/8" here and 1/8" there and the next part didn't fit it just got slammed on.

Exactly, they didn't worry about it, but they didn't have to since the fixtures the sub assemblies got tossed onto were solid and made it dummy proof. Every one of those locator pins was tested before production runs happened. It's why their are 'body in white' cars, they were test builds that were supposed be crushed.

The benefit they had was the fixtures were consistent so while a floor pan may have needed smashing to get it to it, the frame rails were always going to be within very small variance, far less than 1/4". I'd guess less than 1/16 honestly as far as the frame rails went. Everything else references against those and the rockers as I understand it.

As I was saying. You have to meet the existing. Having it on the jig set up correct. It's pretty much fool proof. You just have to see where it's at. Get the platform done first and build up. There are no and I mean no upper body measurements. Only the one's you make or I gave.

Agreed, this is what I've been saying. I only mentioned the door jamb as an indication of how far off the rear frame rail height was.

What I should have done, was to make 100% sure the jig mounting points were measured and ready BEFORE I put the car on the jig. The drawings floating around are a great help but me not understanding how to use the one that shows the '0' line and not understanding it references the top of the rocker was definitely a problem for me and left questions no one seemed to have consistent answers for. . between you're measurement's and explaining that point about the rocker as datum made all the difference in the world.

My car was/is not stable enough to use the existing points as reference and to add more pain, it was in an accident that bent the frame rails. So I'm pretty pretty close as stated to building a new car from scratch lol.

I made a mistake early on not being more careful during my initial setup, that's what I'm trying to correct now.

 

[Challenger RTA]

Since you have it on a jig. If you have the post in the jig holes. mark the post as a tattle tail. The post are adjustable correct?

Center line.

 

[Cuda416]

Since you have it on a jig. Center line.

Centerline I can establish with a string line and plumb bob. Laser is way simpler but I'm not at all worried about that until it's level.

 

[Challenger RTA]

There are some other measurements that I cam across. I post them. I think there MCR I find them.

Even the best of the best use a string.

 

[Cuda416]

There are some other measurements that I cam across. I post them. I think there MCR I find them.

Thanks again, I really do appreciate your input and hope I'm not coming across as argumentative. I'm paying attention to everything you're pointing out, you can be sure of that.

 

[Challenger RTA]

This is something someone posted somewhere. Might be of help. 40 1/8" seemed to be a better number. If it's to long the fenders won't close the gap a the door. find what works for you. 40 1/4"? In short the body is built from back to front

 

[Cuda416]

This is something someone posted somewhere. Might be of help. 40 1/8" seemed to be a better number. If it's to long the fenders won't close the gap a the door. find what works for you. 40 1/4"? In short the body is built from back to front View attachment 150536

That's exactly what the challenger front clip behind my shop measured out to. Great to have confirmation.