I bought a cheap feeler gauge (fan type) and drilled a .070 hole through several of them, about 3/8" from the end. The pilot of the counterbore goes through that hole, but is small enough to stop the outside cutting area. For example,I use a .032 and .030, when I want a depth of .062. This is not exact, but works great.
A.T. http://www.customknives.com
A.T. http://www.customknives.com