Underside reads, "BONNEY S. PAT. AUG 2, 70". Very early patented tenon cutter or hollow auger in excellent condition. Charles S Bonney of Syracuse, New York was the patentee. Used in a brace and likely one of the very first patented adjustable hollow augers. Excellent condition.
Patent information can be found here via datamp.org
**All edge tools may need to be sharpened/honed before use**