Wait, hard water coats the grounds? I always figured bad water just tasted bad on its own, not that it was actually messing with the brew itself. Did you test your tap water at all, or just grab a pitcher and hope for the best?

Man, that is such a stretch. One dude asking a question and suddenly you act like you discovered fire? You probably would've been fine anyway, checking air lines ain't that deep after two years of muscle memory.

That manual driver thing used to seem like a waste of time to me, figured a impact was just faster and fine. But after wrecking a second guard on my Makita last spring I finally tried your method with the Loctite and a hand tool. Night and day difference honestly, the screws stay put and I haven't had to fight one since. Still keep a tiny impact in the truck for other stuff but this one stays hand tight now.