We describe the design and construction of an ultrahigh-vacuum molecular beam epitaxy (MBE) system for the growth of metallic heterostructures, particularly magnetic metals, and alloys. The system, which was specifically designed to be both cost-effective and compact, incorporates an "axial" design with a large source to substrate distance (>69 cm) to meet demands for high uniformity, low deposition rate, and compatibility with nanolithographic masks and templates. The growth and in situ characterization capabilities are specifically tailored to metallic film growth allowing for greatly reduced costs in comparison to commercial MBE systems. We demonstrate the performance of the system via a study of the controlled epitaxy of Cu(111) on Al2O3(0001), a useful substrate/buffer layer combination for the growth of many magnetic transition metals and their alloys. Exploiting the three-dimensional nature of the growth at room temperature we are able to control the in-plane crystallite size, independent of the surface roughness, by varying the deposition rate. (C) 2004 American Vacuum Society.