I needed to make a new zero clearance insert for my tablesaw. In the past, I've used a piece of UHWM plastic. I didn't have any laying around, but I did have several scrap lengths of composite deck board. I used one and made the perfect insert. Very dense, perfectly flat, cut, sanded, and most important--jointed--clean as a whistle. I was able to take a very thin slice to make the thickness perfectly match the insert hole without any tearout or chatter. I'm going back and replacing all the inserts I've made with this new material.