Serrated lock washer A8.4 DIN6798 (8 pcs) Torque wrench (1 … 5 Nm) Loosen the screws (4 pcs) that hold the flange at the bottom of the enclosure until you can remove the counter ribs inside the enclosure . Push the screws back to place and insert the serrated lock washers on the screws. Insert the counter ribs on the screws. Tighten all the screws lightly one by one. Tighten all the screws to 4 Nm. Repeat the procedure on the second flange of the enclosure.