A keyless arbor device for securing a tool, such as a drill bit, to a driver, such as a magnetic base drill. The device generally comprises at least one drive key pivotally combined with the arbor. The drive key has a first position wherein the drive key is retracted and a second position wherein the drive key is extended. The device also comprises a threaded member and an outer sleeve combined with the arbor. Rotation of the outer sleeve in a first direction causes the threaded member to move in a first direction and rotation of the outer sleeve in a second direction causes the threaded member to move in a second direction. The drive key is positioned so that as the threaded member is moved in its second direction, the threaded member makes contact with the drive key which forces the drive key to pivot from its first position to its second position thereby engaging the shank of the tool to secure the tool with the arbor.