This paper discusses the design and manufacture of an optical system used in a portable wear metal analyzer (PWMA). The PWMA was developed for the United States Air Force to analyze used aircraft engine of for wear metal contents in the parts per million range. The PWMA uses the graphite furnace atomic absorption technique to detect nine wear metals simultaneously. The instrument has to perform in the field where environmental conditions are particularly challenging. The operating thermal environment spans 75 degrees C and the instrument must withstand a 30 g shock without degradation in performance afterwards. Weight and volume of this stand-alone analytical instrument are limited to what can be carried by one man.