Each practical task has its constraints. They limit the number of potential solutions. Incorporation of the constraints into the structure of an algorithm makes it possible to speed up computations by reducing the search space and excluding the wrong results. However, such an algorithm needs to be designed for one task only, has a limited usefulness to tasks which have the same set of constrains. Therefore, sometimes is limited to just a single application for which it has been designed, and is difficult to generalise. An algorithm to estimate the straight line representing a milling edge is presented. The algorithm was designed for the measurement purposes and meets the requirements related to precision.