Build Your Own Truss Rod (Acoustic Guitar) 

Thanks 👍

Thanks

Yes sir this is single action. Hard to describe a dual action with words only but the front sleeve would be threaded and the nut welded to the round rod. Instead of being welded solid at the other end there would be a washer welded on either side of the sleeve. you get a push pull action that way if that makes sense. A bit more complicated to make. I've never had a need for a double action rod though some people swear by them. I build the neck with about .005 relief built in before gluing on the fret board so the tendency is for the neck to bow forward. Never had a neck back bow although I understand it could happen. I think the built in relief prevents that in my experience.