ncremental sheet forming (ISF) is one the manufacturing methods for sheet metal parts which has an increased rate of flexibility combined with relatively simple and cheap common technological equipment. This paper presents the results of researches on ISF performed on a CNC lathe, for thin sheet parts made of DC04Am mild steel. The main objective of the paper was to establish the maximum wall angle of the parts and its dependence on the main parameters of the process: thickness and diameter of the part, the tool radius, the feed rate, the spindle speed and the lubricating/cooling conditions. The tests were performed with original equipment designed by the authors and the results were commented and presented in diagrams and images of the parts. The main conclusion is that ISF on a CNC lathe can be successfully used for manufacturing conical shaped parts made of mild steel thin sheet, having a certain maximum angle of the parts wall, for small sized batches. The limit values of the parameters analyzed are a useful technological database for engineers.