If you don't need to leave any meat in the middle, what about a 1-1/2" paddle bit (or something similar) straight through and clean it up with a chisel?
Even then, you can drill only as deep as you need to.
A succession of holes bored wont leave much left over to clean out.
Even then, you can drill only as deep as you need to.
A succession of holes bored wont leave much left over to clean out.