The stylus is an important part of the measuring system. During the measurement, the stylus is in direct contact with the part. Cylindrical styli have, compared to other styli, a larger surface area and are used to capture thin walled parts reliably. Depending on the application, different materials for stems and tips are available.
Ruby is the most widely-used material for styli tips. Thanks to its inexpensive price and high quality, it is the standard choice for most applications. It is an extremely hard material, which tends, however, to cause material build-up when combined with certain materials such as aluminium.
A tungsten carbide stem has high stiffness and less thermal expansion, compared to stainless steel.