When attaching the clevis to the control horn on the control surface AND if you use a clevis on the servo end, use something like the drawing to make the connections. Use a lengh of fuel tubing, about 1/4 inch long, and slip it over the clevis onto the body of the clevis. Make the connection to the servo or the control horn, then slip the fuel tubing over the fork of the clevis about half way up to where the connection is made to the control horn or servo. This will keep the clevis from opening up from some un-planned torque.

DS