[Guitar1990]

Hello,

I have a Yamaha acoustic that I'm working on and I've run into something I have a question about. I set up my own instruments but haven't had much experience with acoustic guitars. I am currently trying to figure out this guitars truss rod and am 75% sure I know what's happening but would like to be 100% before proceeding. With the strings off of the guitar, I turned the truss counter-clockwise in order to totally loosen it. I felt it get loose but then noticed resistance as I turned it further to the left. There seems to be a point in the middle of this where it's loose and then turning in either direction has resistance. I am 100% sure that turning it clockwise makes the neck more convex so as to remove relief from the neck when strung up. I am not so sure about turning it counter-clockwise. Is this counter-clockwise resistance the truss rod "maxing out" after totally loose or is this actually making the neck concave in adjustment? In other words, how do I know for sure this is a single action truss rod? Once I know this, I can confidently work to get the neck to flat before starting a fret dress.