(courtesy of FirstGuitar.com)
The following items will help you become more aware of what to look for in a quality, adjustable instrument and one that is inspected and properly adjusted.
The tuning machines should operate smoothly and accurately with the strings wound properly around the tuning post.
Tuning gears of less quality may tune a guitar accurately but will require more time and effort and is generally a difficult task for the uninitiated player.
The neck joint and heel should be stable and secure with no finish cracks around the joint for all guitars with set-in necks.
Electric guitars with bolt on necks should also be stable and secure with no finish cracks where the neck and body join.
For acoustic guitars, the wood bridge should be securely glued with no open gaps.
Except for children’s guitars, there should be no round pearled or black dots that conceal nuts and bolts to hold the bridge on!
The bridge hardware on electric guitars should be secure and stable.
The adjustment screws in the saddles should fit firmly but not tight. Lesser quality hardware tends to have loosely fitting adjustment screws, which can easily become stripped.
The neck should be reasonably level with the top of an acoustic guitar.
Neck angles that are too far forward or backward will tend to have or develop adjustment problems. A helpful visual indicator of a good neck angle is a bridge that is about as high off the top or soundboard of the guitar as the fingerboard. An extremely high saddle on the bridge may indicate a neck angle that is too far back.
A functional truss rod will usually make slight changes in a neck with as little as a 1/4 to 3/4’s of a turn.
A functioning truss rod is important for periodically adjusting the neck/fingerboard when necessary to help keep your guitar playing easily. Classical, or nylon string guitars, traditionally do not have truss rods as these guitars are under less tension than steel string guitars. However, some full size classical intermediate guitars include an adjustable truss rod.
String height or action at the nut should be low at the first fret, which results in all six strings being easy to play.
This is necessary for all guitars and even more so for children’s guitars which are generally unplayable before they are adjusted. A good test is to use your 4th finger (pinkie or smallest finger) to gently push down one string at a time at the first fret. The string should not bend excessively. There should be little effort to play the note and the tone should be clear. If this task is difficult to perform, then the guitar may not be properly adjusted. A child would find it almost impossible to play.
The bridge saddle suspends the strings over the length of the fingerboard.
A properly adjusted saddle or individual saddles for the electric guitar, will suspend the strings high enough to have minimal to no rattle or string buzz along the length of the fingerboard but low enough to be relatively easy to play. The strings by necessity have to be higher along the fingerboard than at the first fret to create room for the vibration arc of the strings. Strings that are too high above the fingerboard are not only difficult to play but also cause the strings to be stretched or pushed out of tune when attempting to play notes and chords along the length of the fingerboard.