The Grinder function for highly efficint method of reducing the wide range of material into small pieces. It consists of a rettet fitted with knives revolving in the body in which stationery dead knives are fixed. The dead knives can be adjusted so as to give a maximum shearing action against the rotory knives. The inclined angle of both the rotter's knives and dead knives ensure a constant cutting gap across the whole width of knives. Special features include regrindable knives and easy change of knives and screen makes machine able to give maximum production and economical in operation.