crankshaft grinder for sale berco rtm225. ... BERCO RV20 Valve grinding machines ASSURICH . RV20 Valve grinding machine. RV 20 Precision and flexibility are the key factures of the Berco RV20 valve refacer. The machine comes in three versions, known as the RV20, RV20P and the RV20PP, all of which share the following characteristics: ...