Thanks dick, for the info.

You know the best all around sure-fire simplest way I have found to attach a control rod on .40 size planes using 2-56 rods is the "circle bend end" through a plastic control horn. It is slop free, light weight, and provides 2-axis movement. I have not had much luck trying that method with larger 4-40 rods, primarily due to the size.

The servo arm geometry on the Edge elevator servo and control arm is such that a straight clevis attachment to the servo works fine. I have found the DUBRO Safety Lock Kwik Link (PN 817) or the Hayes HD 4-40 plastic clevis to be strong, good looking and slop free. The only thing I have found is that a metal clevis pin in an aluminum arm rarely fits well. I have no idea if the slight amount of slop is a problem or not; it's just one of those personal little bug-a-boo things.

The aileron servo to control horn linkage is a different matter. It is not a straight line from the plane of the servo arm to the control horn. As the aileron moves up and down there is a certain amount of up and down movement of the control rod at the servo arm regardless of which attachment method you use. That is the primary reason I have felt this installation called for a ball link. Currently I am using the new XHD plastic Hitec arm with the new Dubro 899 HD ball link and H9 titanium pro-link connecting rod. The setup is rigid and slop free.

The SWB servo arm is tapped for a 4-40 ball link and would work also. I'm not sure what the hole in the Airwild aluminum arm is. But I guess I will take another look at the geometry involved with the idea of a clevis vice ball link. My only other thought is that most of my full deflection aileron movement is at very slow speeds that I would think do not put that much stress on the control linkage.