I work as a progressive die designer and I might be able to help with the square knock out in the chassis. What is the size that you need? Are dead sharp corners a must, or can you live with a .010 radius on the corners? Anyone know what type of metal is used for the chassis of the player? It looks like some sort of stainless steel. Also what is the material condition IE: tensile or Rockwell hardness using the C scale?