Here is an Aluminum plate or bracket. It’s app 10-1/4″ x 10-1/4″ x point 385″ thick. This is machined. There is a cutout near 1 end, app 2-1/2″ x 2-1/4″. One side is polished. There are eight 5/16-18 thru holes and there is one 8-32 thru hole near opposite corners.