I had hollowed out a green piece of Pecan a couple of years back down to depth of about 15.5" and had a nub about 3/4" H x 1/2" D that came to a point. The piece had some severe checks starting and I stopped and added some "biscuits" out of Mesquite to stop the crack developing. Now after 2 years drying, the Pecan is extremely hard and I was not able to get a scraper to work removing the nub. The thought came to me to use a Forstner bit to remove the nub but how to prevent over boring. I then came up with idea of adding a collar of 1" PVC the length of the 1" drill bit and extension to act as a stop to only drill down to a flush surface. It did work and the had to do minor work to smooth the interior to a reasonable finish and sand. Opening is about 3"D so not overly inviting to check the interior finish. drill stop.JPG