The primary objective of this research is to develop surface models of machining processes to simulate machined surface profiles and analyze their structure. In this paper, fractal analysis is used to discover and characterize the variational pattern of turned surfaces. This analysis provides a means of explicitly stating the precision of a machining process. The results are used to further test the validity of the concept of fractal dimensions at tolerance scales and to establish a relation between surface models, experimental surfaces, and fractals. Based on these results, a more complete model of turning is available to designers for choosing process and design parameters and for comparing the precision between competing machining processes.