The 35°-diamond-shaped insert with simple grooves of coated and uncoated carbide tools were used in turning tool steel bars (23 HRC) with the objective of describing the wear behaviour of these tools based on the flank wear data. Machining tests were performed under wet and dry cutting conditions at various cutting speeds, while the feed rate and depth of cut were kept constant. A certain strategy was established in order to obtain smooth initial wear and avoid concentrated impact load that could trigger chipping when machining was started by making a 5mm precut entry. It was found that the coated carbide tools were superior to the uncoated carbide tools and their flank wear grew smoothly. By linking the machining operations and the tool life curves obtained using the flank wear data, the wear behaviour of coated and uncoated carbide tools was described.