If you're using a Futaba radio, don't cut all the arms off those servo horns just yet. Once you get the servo centered electrically, I.E. as has been explained in previous posts, install your horn of choice. If the arm is not exactally 90 degrees to the servo, then remove it and try another arm on the same horn. Futaba offsets the splines so none of the horns lines up in exactally the same place. It enables you to get the horn exactally where you want it without resorting to the radio to set your subtrims. Kind of a throwback to the days when radios didn't have subtrims.......

I don't know if this works for any of the other MFR's though....


Andy