This paper presents a study of the influence of tool rake angle on the main cutting force for machining rotational parts by sharp cutting tools. A special dynamometer was designed and produced to measure the forces for this purpose. Two strain gages were placed in the proper position onto machine tool and cutting tool. Replacements of the tool caused by cutting forces were sensed by these proper placements. The well-known material, AISI 1040, was used in the experiments. Main cutting force (F-c) was measured for eight different rake angles ranging from negative to positive and five cutting speeds while depth of cut and feed rate remaining constant. As a result of experimental evaluation, cutting force decreasing trend was observed due to rake angle increasing in positive. (c) 2004 Elsevier B.V. All rights reserved.