Tuner Problems

[Bluesdriver]

I've done a few builds and some of them have the following problem: while you turn one of them tuners the pitch of the other strings also change, making it rather difficult to play in live performances.

Also the CBGs that have this problem are sort of difficult to keep in tune, which makes me think that these problems are related.

This it my first post, it's great to know that there is such a great community devoted to CBGs!

Reminder: the tuners were properly installed in the builds mentioned above. I will post pics as soon as I can.

[The Capo Kid]

 It could be a number of things , temperature plays a big part going from place to place , neck bend also , if your tuning to pitch and the string is changing I'd say neck bend , some of mine are hard to tune they don't need to be pitch perfect it's a cigarbox guitar it's all part of the charm : ) .

[Bruce Myers]

I would agree with The Capo Kid, most likely it is the neck/s bending. If the pitch/tuning of the other strings change while tuning one string there is flex somewhere. Sometimes the box lid can bow under tension too. Many times the neck bowing can occur inside the box where the recess for the lid is cut out leaving that portion of the neck a little on the thin side and subject to bowing/flex. In either case you can usually fix these problems with a little reinforcing. 

[Bluesdriver]

Thanks for the answers. I forgot to mention that I used nylon guitar tuners (classical style) on the builds, but I string them with standard steel strings, do you think it might be related to the problem?

[Richey Kay]

I suppose it's possible. Do you have a picture of one of your necks and how you attach it to the box? This would help to diagnose the problem.

[John Sawyer]

I'd agree that this is likely neck bend... When restringing a real guitar, you get the same effect to some degree...  I definitely see it on a CBG that has sat for a few days and is nearly 1/2 step off (new strings)...

 

Fortunately, they're normally off similar amounts, so just keep playin'.     Like Seasick Steve said about his Hudson Hubcap guitar:  "It don't sound too good..."     (which is part of the charm, like Capo Kid said...)

 

[Jim Woods]

I find it takes three or more series of tuning to get a CBG in tune making up for the neck bend. However once tuned, mine with the thru necks really say in tone with themselves very well.  I keep one on the car rear deck behind the back seat in 100 to -10 degree weather & bring it in my office for a "sanity break"  I am amazed that it sometimes so cold there is frost on the tuners & it plays very well - not necessarily to a perfect "G", but the intervals are correct.  You might look if you have any weak spots in the neck ie: where it thins down to allow relief for the box top.  This should be evident in visible bowing - 

But if you are playing in live performances, you are well ahead of me -  P:LAY ON

[Slowpaw Steve T]

the humidity in a crowded hall plays hell with wooden instruments, not to mention a marquee in the rain! neck bend should not be a problem with a good build, sealed tuners are more precise, leave the guitar where you're going to use it for a couple of hours before you tune it, though humidity may still affect it so get one of those Snark clip on tuners to keep an eye on it during a performance (-:

[Bluesdriver]

Finally pictures.

[Wade]

I find that nylon strings can take a very long time to stretch until they are stable. Maybe try steel strings to see if results are the same.

[Bluesdriver]

Unfortunately I think that's not the case, as I said earlier I strung my CBGs with standard steel strings.  

[Bluesdriver]

Yesterday I put nylon strings on the CBG and the problem simply disappeared, it still happens with steel string though.

[The Phrygian Kid]

If you've ever had a guitar with a whammy bar then you know all about this already. Get the last string right, it screws up the ones you already considered done.

All this reciprocal and cumulative tension, it's a balancing act. And yes, it takes time to settle in.
Guys thought already of the neck bending. This is very valid. Let me give you a few more (same thing) ideas.
1. If your tailpiece is suspended from a tailgut, that will cut into the edge of the box more with more tension
2. Your bridge will compress the top more with greater tension.

These things all result in allowing all strings to make their journey from ball end to tuner post in a straighter line, detuning all strings somewhat. Then you recrank em, and whaddaya know, you're in a vicious cycle.

I do not miss the locking whammy bar days, those bastards were a nightmare with this