How to set up an acoustic guitar?
To set up an acoustic guitar, you will pay close attention to the nut, bridge, and neck adjustments. First, take a close look down the edge of the fingerboard and note how straight it is.
Also check for any back-bow, forward bow (relief), humps, and high or uneven frets. Also check the nut to ensure the slots aren’t too deep. The bridge saddles should fit properly and work efficiently. Make sure the fingerboard and bridge match. You will then need to loosen the strings and truss rod to clean and lubricate the truss rod. Make sure you loosen the truss rod nut first to avoid shearing off the nut.
Then, use a small brush or compressed air to clean out the surface, then apply a small amount of lubricant to the threads on the inside of the truss rod nut, but be careful not to get any on the wood. Then reinstall the nut until it is snug.
Next, hold the guitar in the playing position and use an 18-inch straightedge to determine relief. If the neck is bowed forward, tighten the nut until the straightedge lays flat on the frets. If the neck is in a back bow, loosen the but until the straightedge lies flat on the frets.