It is a hollow auger made for cutting round tenons on the end of stock. Usually a spoke pointer is used to "pencil sharpen" the end of the stock so the hollow auger will accept it. The tool was commonly used by wheelwrights to produce spokes but can also be used to make chair spindles. The round part with holes allows for different diameter tenons to be cut. The cutting blade is on the bottom and is presented to the workpiece at a very shallow angle to allow for cutting the end grain.