Internal grinding machines are used when the workpiece has bores or an internal cylindrical surface. In modern CNC universal cylindrical grinders noncircular grinding is also possible. At Surplex you will find used cylindrical grinders with different distances between centres, centre heights, grinding lengths and grinding diameters!.ANCA CNC Grinding Machines - Crotts and Saunders. ANCA Grinding Machines. Founded in 1974, ANCA has a reputation of being a world-leading manufacturer of CNC grinding machines. With its blend of high-level engineering, software development and practical experience, ANCA continues to support the industry with innovative products. YouTube.