diamond frame

Finally got my 30 roadster down to bare frame and started doing some measuring. Apears the frame is diamond 3/8 of an inch. I read somwhere where they said no more than 1/4 inch or you can have dog tracking. My question is , what the best way to fix the frame. Is a frame shop the best way. Thanks Dave

 

you can pull it with a come along

corner to corner on the long side ,

make sure your measuring is not off. a variation in where you are measuring can make a huge difference cross measuring

 

Even the difference from one side of the tape measure to the other side can fool ya... and don't assume that the frame horns are true and even, or that they EVER were... measure from points SURE to make a difference.

 

Thanks for the help, Im measuring from the radiator mount holes in the crossmember to the rear cross member corners. Dave

 

I have found always use two people when measuring. one to hols the end and the other to do the reading. ALWAYS have the same person reading or holding so they use the same point.

 

Measure the length of each rail first from the points you will use to X check for a diamond condition, one rail may be shorter, or the holes your using for your checkpoints may not be symetrical side to side.

 

Setting up a trammel point gauge can be extremely helpful.
A few string lines, sides and center can aid in the squaring process. Give a good place to measure from. For things that are built in a symmetric trapezoidal fashion, working off center is best.

There's some prints of frames floating around here, wescott has some but I hear mixed reviews on accuracy.

 

also, I would level your frame first. Throw a level across the front x-member and across the rear x member. shim as necessary. sometimes you need to put weight on it to hold it where you want it.

 

One other thing to check for is twist. Run a string between your measuring points, run another in an X pattern. The strings should touch where they cross.

 

all the above, but also check suspension member squareness..where the front and rear axles will mount

because thats where your "dog tracking" is going to come from

if your front and rear suspension members are not even and square, and in proper relation to one another
the length of a frame rail wont matter

 

Thanks all for the great advice, I leveled and measured and remeasered again, I keep coming up with the 3/8 inch diamond. I will recheck the lenght of each rail tomorro. A little info on the build, my sons and I are building our first Rod. The car is a 1930 roadster that we plan on making old school. It was mocked up a little bit from the previous owner, Also they added 5 inches to the lenght of the frame. This may be where some of the problem came from. The car has a olds rocket 88 for power and I believe they added lenght to the frame so the firewall could stay stock. Thanks again. Dave