Sorry, I don't think I was clear. What you want to do to stake the roll pin is to take a centre punch (I usually use my automatic one) and locate the point of it about 1/8th of an inch from the edge of the hole on the arm and create a small indentation. If done right, the hole be ever so slightly "mashed", so that the arm material can grip the roll pin securely. Same idea for the spherical bearing used in the elevator control bellcrank.
