Center assembly squaring, what am I doing wrong?

My build is coming along great but have run into my first problem and cannot figure out what to do. My center assembly is not square and loosening the A, B & C bolts does not allow any adjustment at all. This thing is very solid. I even took tension bolts C out completely and bolts B and A are very loose but still cannot even force it into square.

What am I missing?


You have to have all 4 rails in to measure it.

If it still isn’t “perfect” It should say in the instructions and the FAQ’s to use it for a little while (do some plotting, etc.) and then try it again to break it in a bit.