In this study, the effects of cutting speed on tool wear and tool life when machining Inconel 718 nickel-based super alloy have been experimentally investigated. A series of tool life experiments has been carried out using silicon nitrite based and whisker reinforced ceramic tools which have two different geometries and three different ISO qualities with 10% water additive cutting fluid. The experiment results show that crater and flank wears are usually dominant wear types in ceramic square type (SNGN) inserts while flank and notch wear are dominant in round type (RNGN) inserts. Minimum flank wear is seen with SNGN tools at low cutting speeds while it is seen with RNGN tools at high cutting speeds. (c) 2006 Elsevier Ltd. All rights reserved.