That photo is the inside of the scale. The hole you see is for the 1/16 th pin for the hinge . This is all pretty tiny stuff . Looks big here though. That slot I made is maybe 1/4 inch long?
But what I was able to do was make a slot for a section of rod to drop into spanning across the crack to bridge it adding strength. I didn't want to rely on whatever glue I could work into the crack itself as this can be an area under stress. The rod in epoxy just makes it strong and I don't have to depend on the thinness of the glued scale alone.