A method is described for building a mechanosynthesis tool intended to be used for the molecularly precise fabrication of physical structures--as for example, diamond structures. An exemplar tool consists of a bulk-synthesized dimer-capped triadamantane tooltip molecule which is initially attached to a deposition surface in tip-down orientation, whereupon CVD or equivalent bulk diamond deposition processes are used to grow a large crystalline handle structure around the tooltip molecule. The large handle with its attached tooltip can then be mechanically separated from the deposition surface, yielding an integral finished tool that can subsequently be used to perform diamond mechanosynthesis in vacuo. The present disclosure is the first description of a complete tool for positional diamond mechanosynthesis, along with its method of manufacture. The same toolbuilding process may be extended to other classes of tooltip molecules, other handle materials, and to mechanosynthetic processes and structures other than those involving diamond.