An aluminum alloy molecular beam epitaxy chamber has been constructed and its vacuum properties tested. Prior to the construction an oil‐free lathing technique was developed and was applied to the inner surface of the chamber, which resulted in an extremely low outgassing rate of the order of 10−11Torr 1/s cm2before bakeout and less than 1×10−13Torr 1/s cm2after a 100 °C, 45‐h bakeout. This low outgassing rate of the material enabled the chamber to be pumped down from atmospheric pressure to the order of 10−10Torr in 23 h of evacuation without bakeout and in only 6 h with bakeout. With this short pumpdown time and its great reduction in bakeout temperature and time together with its reduced weight and the low cost, the aluminum alloy ultrahigh vacuum system provides us with a remarkably convenient tool to access the ultrahigh vacuum region.