Apparatus - Keep the apparatus dry and clean. Apply a drop of oil to the screw threads to prevent them from rusting.
Check if: - The measuring needle is straight and the pointer (above 100 N) increases without shocks. - The red maximum pointer is straight and works well. - Wether the black pointer returns to zero after a measurement, within the black marking. By turning the plunger and pulling it out a little the pointer must return to zero. - The apparatus leaks oil. - The displacement of the plunger is not too big. If so it needs to be refilled with oil. To do this: Open the plug of the oil filler (3) with a socket-head screw wrench. Remove the ball of the oil filler by shortly turning the apparatus (use a cloth). Holding the filler at the highest possible point, pour in the spare oil (included in the bag of tools). Be sure the plunger is in the lowest position. Replace the ball (preferably a new one) and screw the plug in, remove overplus of oil with a cloth.
If the apparatus is still not functioning it must be returned to the producer/supplier for repair.
Sounding cones - Keep the cones dry and clean. Apply a drop of oil to the screw threads to prevent them from rusting. - Check the wear of the cones by using the cone check (06.01.26). If you are measuring the diameter with a caliper gauge: If their base area is 5% less than the prescribed base area they should be replaced. If the conical surface is damaged, the cone must be replaced. .