US Patent 7488146 Large holesaw mandrel assembly

A holesaw mandrel has a mandrel body with at least one bore, a pilot drill bit bore, and a first end coupled with the body. The first end is coupled with a driver. A second end extends from the body and includes a threaded spud. A sliding collar is axially movable on the mandrel body. The sliding collar includes at least one pin extending the bore in the mandrel body. A resilient member is positioned adjacent the threaded member to provide enhanced securement of the holesaw. The sliding collar is magnetized to prevent withdrawal of the pin from the holesaw. A positioning member is in the pilot drill bore to provide a desired orientation of the pilot drill bit.