Lapping experiments at various loads showed a decreasing bed thickness with increasing applied loads. Comparison of these results with the particle size distribution, measured before and after abrasion, revealed that at higher applied loads more particles will fracture during abrasion. This also may be the cause of the slightly decreasing bed thickness in time. A quantitative interpretation of the particle size distributions was not possible, since there was a significant amount of glass present in the slurry. Nevertheless, it was clear that the actual particle size distribution under the workpiece is different from the original particle size distribution.