https://buildaquiltingframe.weebly.com/
this was my first quilting frame. It works for a dsm. I tried to convert it to use with a long arm and was unhappy with the result, but it was fine for my regular straight stitch Brother. Just realize you won’t have all the advantages of a long arm, but it is a decent start. I was thinking this might give you an idea of how you could rebuild what you have.