Tube spinning is a continuous bulk forming technique used to produce seamless tubes. In the last six decades, tube spinning process has been applied to a wide range of engineering products; especially in automotive, aerospace and nuclear industry. However, understanding of the process mechanics is limited. Key references were published about 60 years ago. This paper investigates tube spinning mechanics using physical trials and a numerical model. Mechanisms of material accumulation, wave, bell-mouth and diametral growth in tube spinning are investigated and their mechanisms explained. Numerical model results show that both equivalent plastic strain and plastic strain rate are localised in the region immediately under and ahead of the roller producing highly non-uniform strain distributions and that the process reaches steady-state at an early stage. The stress state is dominated by compressive normal stresses in all three directions.