I'm about to start assembly.
Currently, the frame has been blasted and powder coated, but I just realized I have no idea whether it's straight or bent.
I'd appreciate any input from you about what measurements I can do to determine if the frame is straight.
If you type this into Google
frame measurements site:www.mtfca.com
You will get this:
Start here good info
Bill, measurements are not really necessary to check if frame is true. A sagging frame can be checked by stringing a tight line along the top of each frame rail. It must be tight. This will tell you if the frame has sagged. Each rail will not necessarily be the same.
Out of square can be checked by measuring diagonally from one corner to the opposite at the other end. A joiners trick is to put a nail at one end of a suitable length of timber, park the nail in one corner and mark off at the other end. Swap the timber over and mark off on that side. Any difference will show any out-of-square.
Hope this helps.
Allan from down under.
Allan's method is what I used...before sandblast and powder coating. But that shouldn't be a big problem if you don't see a big kink or sag by eyeballing down the frame.
Mine was low on the right side by about 1/4" which we repaired with a long timber and blocks on top of the frame, and a few large C-clamps and blocks under the low point. With the tight string in place, we had to pull the frame up about 1-1/2 above straight for it to spring back to even.
I don't think you would damage the powder coating with rags under the wood blocks.
Minor damage to powder coating can be touched up with cheap enamel paint (even a spray can might work okay, but may need several coats to fill). On a frame? Who is going to see it?