smacfe, I think you are correct, back in the 70's my first low winger was a Kaos, and I had at least four total. I never had the wiggle and it was not common in my area altho I did hear of people having that issue. It was not uncommon back in that period to put a Z type bend where the wire exits the fuse. I never did that, I tried to make the rod straight and the wire as short as possible. Every time I noticed that pushrod condition on some ones plane I would show them how the control surface could move and was not stiff. I never studied the problem of wiggling because I did not have it on any plane. It can be that the Kaos is more sensitive than other designs and when a loose push rod is used it wiggles. I don't believe the servos in general would cause the wiggle they weren't that bad (were they?) and we have people reporting having the problem recently , some of them very good builder fliers. I like your explanation, makes sense to me. It will be interesting to see the wiggle induced and corrected by someone.