The issues of nanotechnological maintenance of indicators of the quality of the plates of pendulous accelerometers are considered. The application of two-side lapping with bounded abrasive to provide the required flat-parallelism of plates is justified. The possibility to form the ledges and hollows as parts of the design of the plate, by the method of plasma-chemical etching is shown. The procedure of ensuring the uniform thickness of thin film coatings, which are used as the mask for the plasma-chemical etching, is suggested.