I have a fork that is not original to a frame, and I really need to make this work. With the headset installed, the top lock nut has enough of the steerer threads in it to make me comfortable with the setup (about 3/4 of the nut is threaded onto the steerer). But this bike originally called for center pull brakes which means I need to add the brake cable hanger to the headset. So . . . how much of the top lock nut needs to be threaded onto the steerer to be safe or adequate? Any suggestions, opinions, recommendations are greatly appreciated.