Quick Repair Tip: Troubleshoot neck & bridge alignment without glue

[vintageparlors]

If I've learned one thing about working on old parlor guitars it's that the only thing predictable is that nothing is predictable. For example, there is a "rule of thumb" that goes something like if a straight edge placed along the frets and extends to/sits just above the bridge then a proper neck angle is..... It didn't take long for me to figure out that that "rule of thumb" doesn't work well for lightly built acoustics with poplar necks yielding plenty of movement under tension. Too many times I would locate and glue either the bridge or fretboard into place only to find that so much body/neck movement under tension required one or both to be removed and reset.

Then I figured out that you can improve the certainty with which these features can be plotted without jumping the gun and gluing features, particularly the fretboard onto the neck or the neck into the neck block, into final position. Here are the two key elements to one approach to establishing neck angle and bridge position, under full string tension, but before glue.

1. Using tape to secure the fretboard to the neck
2. Using threaded insert to secure the neck to the body during the plotting stage

Taping the fretboard to the neck allows me to make adjustments to its position along the way. For example, many times a vintage parlor rebuild includes a footprint of a prior bridge that the new bridge needs to cover/hide. In this instance the bridge location is "fixed" so the bridge can be glued down and the neck angle established based on the actual bridge location and height. Using the right tape and enough of it, I've actually been able to engage the truss rod slightly, which is an added bonus.

I can simulate full string tension by attaching the neck assembly to the body by virtue of the threaded insert, string up the guitar and tune to pitch. The tape has no trouble holding the fretboard to the neck and whole guitar can now react to full string tension AND still allow me to make adjustments to the final location of the fretboard on the neck after the "tension test" has run its course.

Adjustments for vertical and horizontal alignment of the neck are a fact of life so having the flexibility to dial in not only the proper neck angle but also best intonation possible is a life saver when it comes to getting the guitars' geometry just where you'd like it to be, with as few headaches as possible.