View Archtop Setup
ARCHTOP GUITAR SETUP is like any other guitar setup with the exception of the adjustable floating bridge which is unique to the Archtop guitar.
The HISTORY of the floating bridge will be a big help in understanding why the floating bridge is unique to the Archtop guitar. The traditional original Archtop guitars were made with floating adjustable height bridges, so that when the guitarist needed to play louder, which was why the Archtop was designed in the first place, they could simply raise the height of the strings, with the use of the bridge height adjustment thumb screws and avoid fret buzz. In so doing, if the string were raised or lowered quite substantially, this might affect the intonation and then, the floating bridge which was not glued or fixed to the top of the guitar, could be moved slightly backward or forward to correct any intonation problems that might occur from this adjustment.
The ARCHTOP BRIDGE SETUP is very simple. You only need to know first the fret board scale of the guitar you are setting up and the rest is quite simple.
The SCALE of any guitar is identified and or calculated approximately by the length of the strings from the nut to the bridge. For E.g.; a 25 ½” scale guitar, which was the original scale of the traditional Archtop guitar, measures approx 25 ½” from the nut to the bridge saddle.
The NUT being the grooved string spacer made of bone, ivory or plastic etc that the strings pass over at the start of the fret board and positioned near the headstock.
The SADDLE being the grooved piece which spaces the strings and sits on the bridge above the thumb wheels at the mid lower body end between the tail piece and the fret board.
Many ARCHTOP GUITAR SCALES today are made with slightly smaller scales like the popular 24 ¾” scale and so most regular scales will have a string length measurement somewhere between 24 ¾” and 25 ½” depending on the fret spacing of the fretboard which also constitutes the scale size.
POSITIONING THE BRIDGE is done by reducing the tension on the strings so that the bridge can be easily moved and positioned to its scale length. When you have positioned the bridge to this position by measuring the distance from the nut to the saddle you can tighten the strings and tune the guitar to the open strings. With all the open strings tuned, each open string should then match the note of that string played at the twelfth fret. (Which is exactly one octave higher) If the notes at the twelfth fret are sharper than the open string then that will mean that the bridge will need to be moved back a little towards the tail piece until matching in pitch and if the notes are flat at the twelfth fret that will mean that the bridge will need to be moved forward towards the fret board a little. Repeat the procedure by tuning all the open strings again and then checking all notes at the twelfth frets until they match perfectly in tune.
REPLACING STRINGS on an Archtop with a floating bridge is quite an easy practice and there are a few way of doing this. The FIRST and quickest way, is to change one string at a time so as to keep the bridge in its correct set position. The SECOND way of changing strings with a floating bridge and the procedure for doing so when it is necessary to have to remove all the strings to clean the fret board etc. First acquire some light paper masking tape. (Make sure it is not very sticky as this may damage a very old finish when removing. Try sticking the tape on something first to take remover some of the stickiness before applying to the guitar) Then by placing and sticking small strips very gently to top of the guitar body around the base of the bridge, this will then ensure that the bridge can be removed and returned to the set position after you have cleaned the fretboard and begin to restring the guitar.
TRUSS ROD adjustment will most likely be necessary if you decide to change string size as the tension of the strings will most likely affect the balance and level of the fretboard. At this point, even though I personally make adjustments to my actions etc via the truss rod it would be more responsible for me to recommend that you take your guitar to a good guitar repairer to make this kind of adjustment unless you have had a lot of previous experience in doing this adjustment yourself.