frame rail measurement - help pls

[velrob]

I was trying to lay the new floor in this weekend and somehow my right frame rail isnt quite right. luckily i didnt weld it full in. My left rail could be fubar as well. the new floor has half inch gap between the wheel well and the floor on the right side.

I was installing the left rail while the right was still there (old) and used those measurements but when im measuring point to point on the left side it reads 54" (See attached picture for the 53 1/2 measurement). I didnt have the drawings at the time. Is it possible the rails moved half an inch (old rails that is?). I used the old rail as measurement while installing the new one.

I was hoping someone could measure theirs and let me know the size from the two locations. Edge to edge.

how much tolerance is allowed on the rear rails to be off?

thanks for any help.

 

[daytona kid]

I think I read somewhere that 1/4 is the rule of thumb tolerance. Don't know if this is the same as what you have or if will help. Not sure what your car is but this is for a 68 B-body- coronet/charger/etc..

 

[velrob]

Mine is a 71 charger, sorry forgot to mention that . I already have that drawing you have in the service manual. Service manual didnt have any measurements for the 71 charger.

Does the 1/4 inch tolerance apply to frame rails?

 

[daytona kid]

Just guessing but I'd say yes.. And I think that is what it says in the text above the drawing I posted.

 

[velrob]

hmm some reason my frame alignment diagram says 1/8 inch

and it says use direct measurement. should i be using tram type measurement or point to point?

 

[daytona kid]

Can't help you there. sry.. I just used the drawing and a plumb bob, and marked
it out on the floor of my garage. I also noted measurements before I removed the old parts.

 

[velrob]

I know that some measurements need a plumb bob or tram but im trying to understand if these drawings i have are a point to point measurement or should i be using a plumb bob as well

 

[daytona kid]

I should mention, all that I replaced was rear partial frame rails, trunk and interior floors, and 1/4 skins. While doing the rails I measured point to point where I could, but the plumb bob let me get to points/places I couldn't get point to point. But more important to me was that I also transferred the points with the bob to the shop floor. I basically had the rear part of the top view drawing in full scale on my shop floor. I leveled my car on adjustable stands but my floor was not perfectly level so I took that into consideration when recording vertical measurements. My car was straight and mostly together tho, before cutting off the rusty stuff. I even used lateral measurements to the wall of my shop. You just have to sit down and figure out the best way for your specific situation, as in what all you are replacing. If things are bent or missing then you have to rely more on the drawing/s. The drawing helped me somewhat but I made and recorded a lot of measurements that it doesn't have on it. I tend to always try to figure out a better or more accurate and sometimes easier way of doing things. Sorry if I'm no help maybe someone else will chime in that can give you better/more specific tips.

 

[velrob]

The drawings gives me the measurements I need (for the rear rails) but when it says point to point does it mean without using the tram method? I was fiddling with it yesterday resetting one of my rails and I have it (i think) where it needs to be.

This is my first restoration (or any body work for that matter). I have friends that help me. Im just not accustomed to reading frame dimensions. When it says point to point, i'm assuming I would measure directly with a tape measure? Like the picture?

I just need someone with experience to help me decipher the instructions ive also attached the full page that was included with my measurements.

thanks.

 

[daytona kid]

I know nothing about tram method. I used a tape. Sometimes new parts don't fit just like the old ones. And remember welding heat will make things move, skip around while welding slow. Good luck.

 

[velrob]

Im ok with the panels so far i didnt weld any panels in the back yet

im trying to get the rails back on properly.

im trying to find this measurement to make sure the angle is correct

if anyone has this measurement its all i need. i cant find it anywhere.