A standard toolholder is disclosed to be mounted on any one of the several cross-slides of an automatic screw machine having uniform distance between the slide mounting surface and the cutting plane parallel thereto. The toolholder assembly includes a holder base receiving a cylindrical shank of a tool-holder on the front of which is mounted any one of a variety of tools, such as dovetail, circular, flat, cut-off, shaving, knurling, burnishing, stenciling, single roll threading, recessing and boring tools. Such toolholder assembly provides standardized mounting heights for all such types of tools and provides for straight or off-set mounting of the toolholder relative to a perpendicular or in line to the spindle axis. The foregoing abstract is merely a resume of one general application, is not a complete discussion of all principles of operation or applications, and is not to be construed as a limitation on the scope of the claimed subject matter.