# Stress on a Guitar Soundboard when converting to Tailpiece

1. Oct 22, 2014

### Bullpuppy

I do have a question on a project that I am doing now (for my personal enjoyment)

I bought an nice handmade classical guitar that was dropped on the tail-block and cracking it and putting two nice crack from the end of the guitar to the sound hole. Since I only invested \$100 I decided to use as the basis of experimenting.

I always like the concept of using a tailpiece and build the guitar sound board with less consideration on the constructions needed to support the stresses placed on the bridge by the string.

Kris Barnett has good things to say about them http://www.krisbarnettguitars.com/#!tailpiece/c1ird

I was wondering how to calculate the reduction of stress on the top when using a tail piece and maintaining the break angle through the saddle. The normal classical guitar may have as much as 100 lbs of stress transmitted to the soundboard via the bridge. The bridge lifts up from the rear and down in the front and the soundboard is built to withstand that. When adding the tail piece on guitar usually the strings just go from the tail piece over the saddle. The majority the string tension is now on the tail block with downward tension on the saddle.

But if use a tailpiece and string through the hole on the bridge (causing a steep break angle) then the bridge will torque in a similar way, but hopefully much less.

It sounds like a physics problem to me.

So the question is - on any given guitar with a with the strings tied to the tie-block on the bridge, is converted so that the strings are tied to a tailpiece and the strings are lead through the same holes on the bridge, then what will be the reduction to the stress on the soundboard. for the sake of argument we can say the the string from the tailpiece are running parallel to the soundboard and are at the same height as the holes in the tieblock.

Any ideas would be most appreciated.

Thanks

TIm

2. Oct 27, 2014