Building my first CB uke and when I strung it the the action lifts signifcantly.
The neck is bolted and glued and is firm as are the nut and bridge but the neck lifts under tension.
The sound board is the bottom of the box which was the deeper portion and I haven't glued the lid yet which may help brace it but I don't want to do this if I will need to fit bracings.
I have a piece glued beneath the bridge location just a little larger than the bridge itself and square batons all round the edge inside the box.
Maybe there's a thread already on this subject - I can't be the first!
Any help welcome!
How is the neck connected to the body? It sounds like the box is flexing where it's connected to the neck..got a picture?
Like CBJ says, maybe the lid is "caving in" a bit, which will also make the string height increase.
4 string uke...unlikely to be the neck bending unless you've tightened the strings waaaay too much.
CBJ most likely has the right of it and it's a simple fix, just cut a couple of gussets from fretboard scrap and glue one on either side of the neck location inside the box.
String pressure on a pinned bridge causes the sound board to bend up raising the action, profanity and bracing is the solution to that issue. I'm sure you've seen old acoustic guitars with that problem it's a PITA to correct.
A guitar with a tailpiece exerts downward string pressure to the sound board and can lower the action too much. The solutions are to make a taller bridge to compensate or add bracing to the sound board.
Thanks guys - checked the problem more carefully and it seems the movement is at the neck joint to the box. I just had one bolt through a block on the inside into the neck but another screw and some glue should sort it.
I didn't want to glue anything till I was sure.
Will check the bridge/saddle when I get the neck sorted.
It's my first attempt and it's amazing what you learn when you try doing it yourself. And very satisfying to hear a real note out of it!
Hope that works out for you.
Play us tune on it when it's done. :D
One bolt and one screw now and the action is way down - great result guys, thanks.
Might let you hear it when I learn to play - that's the next project :-)
It sounds like you have the box sandwiched between the neck and a block on the inside. If that's the case the box is probably twisting and it will likely happen again with some time. It's a good idea to have the neck run all the way through the box or some type of bracing that runs the length of the box with a solid way to attach the neck to the box and bracing. It's amazing how many things we learn in the first couple of builds, you'll only get better with each build. Keep on building!
As always, Bruce sums up exactly my thinking as I'm reading this thread.
Sounds like the top - end panel joint is flexing. Reinforce with a glue block.
I tend to use a through neck and a tail piece which will prevent this problem, but the lack of a back will certainly let things flex a lot. The added backing block you have already added should also help keep you out of trouble;-)