In orthogonal cutting, it is somewhat difficult to analyse the cutting operation directly due to the high speed and large amounts of shearing. Instead, analysis of the forces the cutting tool is possible to be carried out, as well as measuring the thickness of the produced chips. Knowing the uncut chip thickness (feed), and comparing with the chip thickness, the degree of chip compression can be determined. Therefore, an experimental study is performed on a lathe in conditions of nearly orthogonal cutting, with ratios between depth of cut and feed (the feed in turning corresponds to the uncut chip thickness) able to assure plane strain conditions (w/t ≥ 10). A cylindrical specimen of an aluminum alloy is used, with a tool having restricted contact length of about 1 mm and rake and clearance angles of nominally 12°.