[embedit snippet="2-columns"] 1. Introduction Coordinate measuring machines (CMMs) are the most advanced dimensional measuring instruments on the market today. Their unlimited versatility allows them to be used for an infinite number of measurements. But the inherent flexibility of CMMs can also make them difficult to implement. If you are new to CMMs, you are probably wondering how to determine which of the many available machines will be accurate enough for your needs and also how to best compare two similar looking machines. Once a CMM is installed, the question of how to calibrate a machine with so many capabilities is often asked. And now, with many new quality initiatives being pushed onto manufacturing and calibration, the big question is how to estimate the uncertainty of measurements being made using CMMs. We will try to answer all these questions...