The city of Orrville is set to try out a new grinding technique on a couple of its roads this spring.  City officials say diamond grinding aims to correct and smooth out irregularities in the roadway, such as faulting and roughness on concrete.  The technique, which the city has not used before, will be tested out on a project on Hostetler Road and High Street.  Orrville’s safety service director says the project is expected to be completed prior to Memorial Day.