The problem of limiting the standard-size range of drive mechanisms for hydraulic excavators and self-propelled jib cranes with a wide unification of their elements is considered. This approach allows to increase the serialization of products to reduce costs in the design and production, increases the durability of machines and reduces the time of development of new equipment.The analysis of the production of domestic excavators and cranes is carried out. It is presented in a tabular version and a sequence of logical steps to provide a systematic approach to the development of rational designs of hydraulic excavators and cranes. The analysis showed that it is advisable to carry out unification on the modular principle of the formation of some units and, first of all, of slewing mechanisms of these machines. The technique of unification of turning mechanisms and winches of excavators and cranes based on unified planetary hydromechanical block modules is proposed. Creating hydraulic excavators and cranes with unified planetary hydromechanical mechanisms allows you to reduce operating costs and improve the quality of drive mechanisms for excavators and cranes, reducing the cost and complexity of manufacturing. Unification on a modular principle and the subsequent cooperation of parts, assemblies and units allows expanding opportunities to increase production volumes, provides interspecific unification of their basic elements.