I have used the inserts a number of times. I usually drill, tap and harder the wood first then if something happens to the threads in the wood I go to the inserts. If they go in too hard you can crack the wood. I measure the insert itself then use a drill bit just over sized of that. You want the brass threads to cut into the wood when you screw them in. These are one of the places I also use Gorilla Glue, it expands and fills in any gap between wood and brass, I have had the epoxy break loose. If they start to back out just remove them and give the Gorilla Glue a shot.