Gears, till now, are considered essential parts in the majority of mechanical machineries. Their applications are so wide that ranges from power transmission and changing of speed ratios between various mechanical units. During their life time they are subjected to continuous wear, fatigue, shocks, dynamic loads which results in gear damages or at least lowering their running performance. Replacing of the malfunctioning gear is, then, necessary. This require the change of both mating gears either through ready stored spare ones (which is normally unrealistic situation) or remanufacturing new pair of gears. This is not a direct case as gears, nowadays, are produced with profile modification which are known only at the manufacturing end. Thus, the user end has to work using the reverse technique to predict the most near acceptable design to manufacture the replacing pairs. This paper presents the parameters to be measured in the malfunctioning gear and the analysis followed that is needed to manufacture the newly replacing pair.

helical gear, modifications, reverse engineering, gear measurement, C# programming