I have limited experience with my McNaughton. I simply don't do many large bowls and rarely have wood good enough to bother with saving the core. I did find that my main problem was the cutter getting below center as I got deeper. Clifton's experience is dead on in my book. I did have one cutter replaced by Mike Hunter and that tool cuts much easier. However if i let it get down at or below center it's the same fight. I do have some Walnut I may core pretty soon. It depends on whether I decide to make platters from it or bowls.