A novel musical instrument tone hole forming tool. A body includes a distal end to be inserted transversely into a musical instrument through an opening therein. The distal end of the body includes sockets spaced about its periphery. Bearings are located in the sockets. A shaft is moveable within the body and includes reduced diameter distal portions which receive the bearings in a contracted configuration in order to insert the body into the musical instrument. The shaft drives the bearings outward from the distal end of the body in an expanded configuration to form the tone hole when the body is withdrawn out of the musical instrument.