M5, Styli straight, tungsten carbide sphere, tungsten carbide shaft
Styli with standard diameters are manufactured in batches with a high amount of spheres and can thus be produced cost-effectively. Styli with special diameters can also be produced as custom-made styli with higher cost or higher amount. The majority of possible spherical materials in this category are hard metal, while ceramic materials are used in inch sizes.
Tungsten carbide is the most common shaft material, it combines a very good stiffness with an acceptable thermal expansion. Only the weight can have a negative effect when using large styli. The straight shaft is the simplest stylus design and the one with the longest usable length. The full shaft length can be used as measuring length. Tungsten carbide shafts represent a good combination in terms of weight, rigidity and thermal expansion.
Tungsten carbide spheres are manufactured using a special grinding process, which theoretically enables the generation of any desired diameter. Hard metal is significantly heavier than other stylus materials, therefore the hard metal version is not recommended for large diameters. Also the accuracy of tungsten carbide spheres is significantly worse than othe materials