Read this post. https://www.stovebolt.com/ubbthreads/ubbthreads.php/ubb/showflat/Number/326262#Post326262
It is much easier going with 3/8" all thread in this application unless you can't live with anything but original. It is much stiffer. I had my son hold one end and push it through, when I saw it I used a screwdriver blade to lift it close and had him push it home.