The irregularity of a machined, ground, hand or machined polished stainless steel surface is the result of mechanical processes employed. This irregularity consists of high and low spots produced on the surface by the tool bit, the grinding wheel or the polishing mop. These peaks and valleys can be measured and used to define the condition and sometimes the performance of the surface. There are more than 100 ways to measure a surface (see section below) and analyse the results, but the most common assessment of the surface texture is by its roughness measurement.