Quality and quantity must underpin every productive process.This is even more true in case of manufacture and sale precision steel balls used for bearings. Surface finish improvements have been possible because of constant studies in material science and technological progresses. Those have contributed to raise up the demand. Satisfying the latter implies machines overloading, machinery are required working more and faster. Higher attention should be paid to mechanical components degradation to guarantee this result. Vibrations emitted by machines during working process are identified as the leading causes of premature failure for stressed elements, as bearings. For this reason, a vibrational analysis has been performed on pre-finishing grinding machines.