Short description of QMSys Tolerances and Fits 5.3: The software QMSys Tolerances & Fits is an engineering program for designers, engineers, metrologists, quality control planers, machinist and its purpose is to save time and prevent human errors in determining nominal and limit values of machine parts. It can be used to choose a fit and determine tolerances and deviations of machine parts according to international, European and national standards.