Centering and fastening device

摘要

An improved internal diameter milling machine for centering and milling valve seats in internal combustion engines and the like. An hydropneumatic system suspends a hemispherical guide or bearing concentric to the headstock-screw lead screw of the inventive milling machine. This suspension allows the lead screw and attached cutting tool to move in a pendular manner in response to 90° horizontal movements of the work piece. The pendular motion results in the rapid cutting of a smooth and concentric valve seat within about two minutes in a virtually automatic manner.