Many critical applications of mechanical systems depend on the holding power of fasteners. Avoiding fastener failure poses a special challenge to manufacturers. Uncompromising quality control must include performance testing, a series of physical tests in a simulated service environment. When such a test fails, high levels of expertise and experience are required to determine the causes and suggest a corrective action. Qexpert is an expert system that integrates the knowledge of experienced inspectors with results from past testing to build a decision-making aid for the novice inspector to shorten the testing cycle and reduce the number of product lots scrapped.