Pre-tensioning forces are, in essence, the application of selective clamping forces on components prior to machining to create a "stress field" envelope that aids the processes of components. Utilisation of pretension forces prior to process offers advantages of increasing component rigidity, thus reducing the deflection from process, and holding the components in a way to counteract the machining forces etc. However, the scientific research of pre-tensioning forces has not been extensively or comprehensively investigated. The aim of this paper is to investigate the impact of applying pre-tensioning forces on thin walled components, and more specifically, focuses on the development of appropriate fixtures to achieve optimal performance from pre-tensioning. Finite Element Analyses (FEA) were used intensively to analyse the impact of pre-tensioning forces on components during machining process considering machining deflections. After the FE models were validated from experiments, stiffness of components under the action of pre-tensioning forces can be predicted for the development of future fixture design.