B67-636 TREPANNING DRILL. A central bit that is operated by the handle, and then a trepanning type hole saw can be slid down the shaft into place and operated by the T-handle. At least that's how it appears to work, but we're not brain surgeons. 18-1/2" overall, steel shaft, the main handle is plated brass with the plating mostly gone and the T-handle is wood with traces of metallic paint. Unsigned. Unusual. From the collection of Jim and Christa Schoenky. Good 100-200