The particle separation processing technology is one of the significantly important production technologies that combine different processes to obtain the desired shape by the particle separation method. The above said and with tremendous progress, both in industry and in human knowledge, the product is expected to have a satisfactory quality at the end of the production process. This paper explains and presents one of the many particle separation processes, which is turning. The paper describes the basic characteristics and divisions of particle separation processing technology as well as the main features of the turning process and the division of turning. Furthermore, the paper explains the tools and materials characteristics, from which the tools are made and used in the turning process. The thread roughness surface is described in the theoretical part, but also investigated and proven in the experimental part. After the theoretical part, follows the examination of the influence of turning parameters on the thread surface roughness. The experimental research presented the results of measuring the treated surface roughness. Also, the taken values of the parameters during turning are shown. After processing the test samples of the same material and diameter and the results obtained from measuring of the treated surface roughness, the theory of the influence of parameters on the treated surface roughness was proved.