In this experimental study, three SiC/Al metal matrix composites (MMCs) with SiC particles of 30, 45 and 110 mum in mean sizes were produced using a melt stirring-squeeze casting route. Machining tests were carried out on the MMCs using cubic boron nitride (CBN) cutting tools at various cutting speeds under a constant feed rate and depth of cut. The effect of reinforcement particulate sizes and cutting speeds on tool wear was investigated. Furthermore, surface roughness measurements were also carried out on the machined surfaces. The results showed that tool wear was mainly dominated by flank wear and strongly influenced by reinforcement particulate size. The MMC containing SiC particles of 110 mum proved to be unsuitable for the machining operation using CBN cutting tools due to the heavy fracture of the cutting edge and nose. In the composites reinforced with SiC particles of 30 and 45 mum, 150 m/min cutting speeds led to the lowest tool flank wear values while 100 and 200 m/min cutting speeds resulted in higher tool flank wear values. (C) 2004 Elsevier B.V. All rights reserved.