In order to explore the effects of the tool geometry on the machining process, the aim of this project is to study the surface integrity generated in the 4142 alloy steel after straight turning with customized tungsten carbides cutting tools prepared with customized geometries, verifying their influence on residual stress and roughness behavior. Square cutting inserts were prepared from K10 hardmetal with PVD TiAlN coating varying edge preparation (or form factor) and nose radius. Taguchi methodology was applied for the design of experiments also varying feed rate. Results showed the major influence of feed rate and nose radius, over surface roughness, with the form factor parameter interfering at the components of cutting forces, which could also affect residual stresses and tool-lifetime due to wear.