The aileron cables run through a series of phenolic pulleys with ball bearing to allow them to rotate freely. At some points, we installed cable guides to make sure the cables did not rub against each other. One particular guide called the finger guide, we mounted in the ceiling of the cabin. They keep the aileron cables apart as they run from wing to wing, The top aileron crossover cable runs through the hole in the guide. Adjusting these cables so the ailerons deflect the specified number of degrees up and down in response to a full throw of the control sticks proved to be challenging. But we got it done to the specification in the manual!