Here are a couple of pics starting with the fitment before any holes were drilled and after.....I'm using 2-56 stainless phillips head and tapping the thread into the steel chassis after drilling the aluminum screen, which were transfer marked with a fresh fine point sharpie. Then the starting drill is as small as I can fit into the smallest drill I have, then increased up to the tap drill size. I tap with the same drill, no tap handle required. Goes fast, but I do use a teflon compound crayon for lubrication. It's like a way that holds on to most of the shavings.