I think most piano hinge style control hinges nowadays have a nylon or teflon tube between the hinge halves and the hinge pins and so, technically should not require additional lubrication. Certainly the ones I replaced on the Piper types did. Regardless of opinions expressed here, we always gave just a squirt of WD40, allow it to penetrate for a bit and clean off the outside. I still adopt this with my Zenith and have never, after an awful lot of years working on the accursed things, found it to be a problem!