I'm thinking you mean these are on the aileron servo output arms. Sometimes the screws bind a little on a burr. Remove servo arm and wire from fitting. Then see if you can run the screw in until the head seats on the fitting or bottoms out in hole. If not, fix threads or replace fitting. If fitting screw can be tightened down fully but still slips on the wire you could file down the top of the fitting slightly to allow more engagement or replace. The wire may just be too small for this fitting also.

One hinge is not going to be enough.

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Good luc