Since the emergence and the subsequent evolution of lean manufacturing concepts, numerous enterprises of different scale and specialties have adopted lean tools and techniques in their facilities with varying success. In general, lean manufacturing related studies have been conducted on large manufacturing firms, such as the automotive industry. Yet, lean manufacturing tools and techniques are also suited for small enterprises. Thus, the main concern of this study is to investigate the success of set-up time reduction efforts (one of the steps needed to achieve 'one-piece flow') in secondary wood products manufacturing facilities on four woodworking machines (moulder, shaper, table saw, and band saw) based on firm size. The first objective of this research is to explore the results of the implementation of set-up time reduction efforts on selected woodworking machines in enterprises of varying size. It is assumed that company size is a major factor influencing the rate of set-up time improvements. To that end, the first hypothesis, which states that 'Small firms are less successful in reducing set-up time through set-up time reduction efforts than are large firms,' has been developed and supportive questions have been corresponding created. While statistical testing of the hypotheses created for this is not possible due to the limited number of participants, speculations about the possible outcome can be made. Thus, for hypothesis one, the data obtained does not show any sign of a relationship between a firm size and the success rate of set-up time reduction efforts. The second objective of this study is to investigate how a firm's productivity is affected by set-up time reduction efforts as related to firm size. With regards to some of the weaknesses of typical small manufacturing firms (e.g. having limited budget and resources, intuitive management strategies including lack of strategic planning), large firms, by and large, are expected to be more successful in increasing productivity through set-up time reduction. To that end, the goal is to investigate results of the set-up time reduction efforts in terms of productivity improvement in manufacturing facilities. With this in mind, the second hypothesis was proposed, which reads 'Small firms achieve lower productivity gains through set-up time reduction than do large firms.' For the second hypothesis, while no conclusive proof can be offered, no sign of a relationship between firm size and productivity gain through set-up time reduction could be found. Another objective of this study is to explore the success rate of set-up time activities on the four types of woodworking machines in industry facilities considering the training activities provided by manufacturers. The aim is to compare set-up time improvement performance of manufacturers between enterprises which trained their workers/operators and enterprises which did not train their employees. To understand the relationship between the scale of firms (and/or facilities) and training activities to improve set-ups, the third hypothesis, which reads 'Small firms are less concerned with set-up time reduction through training than are large firms,' has been developed. For the third hypothesis, while testing is not possible, it appears that there is no relationship between firm size and the level of concern for set-up time reduction through training activities. The final objective of this research is to investigate whether the secondary wood manufacturing firms studied experienced a bottleneck in their production due to the long set-up actions of machines. In order to accomplish this objective, the final hypothesis, 'In both, large and small firms, bottlenecks occur at machines with high set-up times,' has been developed. The final hypothesis cannot be accepted or rejected due to the limited number of responses obtained, set-up time was a frequently indicated explanation for the occurrence of production bottlenecks in secondary wood products manufacturing firms. / Master of Science