The paper deals with the issues of quality assurance in small-scale engineering and repair production. The analysis of machining processes in engineering and repair production should include the monitoring of internal and external defects in pre-defined categories, which are systematized in the form of tables. The aim of this study is to use checklists for assessing the repair quality. To detect internal faults occurring in technical processing of machine parts it is proposed to use a checklist with additional graphs to estimate of the number of faults and the amount of loss across the whole range of defects. The offered form of a checklist shows that internal losses, which can be estimated in the processing of shafts, include those from irreparable fault, reparable fault, and reduced production cost due to poor quality. The authors emphasize that the information obtained should be recorded for all types of products, and it is necessary to compile reports for different periods of time, to study the dynamics of the analyzed indicators. Basing on the analysis of the number of defects and losses, corrective and preventive measures to reduce their occurrence rate should be developed. Thus, the use of quality control tools should be integrated into the identification of processes, the assessment of costs and losses and their recording into reporting forms. The reporting system should contain information on losses from the faults, the cost of preventing defects and control costs. Analysis of the aggregate information on the costs of quality will lead to a reduction in losses from the faults and increase the functioning effect of the quality management system at mechanical engineering and repair enterprises.