Abstract: Methods, systems and tools are provided for controllable adjustment of a removal rate of manually-guided material- and tissue-separating tools and effectors which allow control of the removal rate of rapidly rotating tools, without the need to significantly change the rotation speed of the tool or to significantly change the position, orientation or the geometry of the tool, and in particular, for precisely maintaining work space boundaries during material and tissue removal with tools in rapidly rotating machine tools in surgery and freehand manufacturing for producing free-form surfaces.