The percentage of low-grade material composing the annual hardwood lumber production in the U.S. is on the rise. As a result, finding markets for low-grade and low-value lumber has been identified as a top priority by researchers and industry associations. Computer simulation has been used by the manufacturing industry for several decades as a decision support tool. Simulation programs are commonly used and relied on by researchers and the industry alike to conduct research on various aspects of the rough mill from processing to recovery efficiency. This research used the ROMI-RIP and ROMI-CROSS simulation programs to determine specific conditions that led to optimal part yield when processing No. 3A Common, 4/4-thickness, kiln-dried, red oak lumber in rip-first and crosscut-first operations. Results of the simulations indicated that cutting bills with narrow part widths and short part lengths are conducive to obtaining optimal part yield while processing No. 3A Common lumber. Furthermore, it was found that as the percent of No. 3A Common lumber in a grade mix increases, part yields and sawing efficiencies decrease. The results also indicated that higher part yields will be obtained when processing short-length No. 3A Common lumber between 6 and 8 feet in length. / Master of Science