ABSTRACT
Measurement of geometric errors is required to evaluate the grade of the manufactured gears. Errors such as the composite error, tooth thickness error, profile errors requires special measuring machines such as the rolling testing machine and involutes testers which are not available to all gear users. In many cases the measurement need a master gear for each tested gear which is economically unfeasible. Again, master gears are required for producing templates and special form tools for manufacturing of gears. The present paper faces this problem by proposing a methodology for producing virtual master gears and to use this methodology for computer utilization for indirect assessment based on the virtual gears model (VGM) so that composite and run out errors can be assessed without the need of actual master gears or the need of special gear measuring machines. The methodology of developing a virtual master gear is generated. The model has been tested by measuring various gears and their measured values were analyzed and compared with the virtual gear through special developed software. The model, also, is capable of producing the profile of any addendum modified gear (perfect involutes profile) for the purpose of designing gears.