COMMENTS The screws marked in steps 4 and 6, serve to regulate the hardness of tipper. Screwing alternately 2 bit by bit without screwing at all. Step 2: Screwing these screws with basin in a straight line (fixing screws). Step 4: Screwing the screw from behind with the basin leaning backward(Step 3). Step 6: Screwing the front screw with the basin leaning forward (Step 5).