@danieldd Old post, I know, but did you ever resolve this? I'm encountering exactly the same thing. Only difference is, the pin is not as small relative to the gate-mounted part of the hinge. And in my case, it's "garden gate" mounted, that is, pin pointed up. but the rotation is causing the same issue. The pin is machine threaded, with nuts/washers on each side of the post. However much I tighten the nuts, it still rotates. There's some rot in the post there, and the more I tighten the nuts, they just bury themselves more in the post. So I'm contemplating either plates (say, 2" square) instead of the washers, or perhaps tooth washers. I also kinda like the above-mentioned epoxy idea, just painting on the part of the pin that goes through the post. I would just dread having to adjust it later if needed.