Tunematic Tailpiece Question

[cknowles]

This may be obvious to the experienced builders out there, but it has me baffled.

I've installed the tunematic bridge and tailpiece on my LP copy, and when I set the tailpiece

down real low, my tuning goes out. Intonation is consistent at the 12th fret, the strings are

close but not touching at the first fret with the string depressed at the third fret. Problem is

that the third fret note is about 30 cents high. When I raise the tailpiece to about 1/4" off the

body then retune, the tuning is spot on with no intonation issues at all over the complete

length of the fretboard.

Looking at it mechanically I can't understand any reason for tailpiece placement to affect tuning at all.

The string length between the nut and bridge is unchanged. Bridge height is also untouched.

Any suggestions?

Thanks

Chris

Here's my guitar Crick

[RGman]

This may be obvious to the experienced builders out there, but it has me baffled.

I've installed the tunematic bridge and tailpiece on my LP copy, and when I set the tailpiece

down real low, my tuning goes out. Intonation is consistent at the 12th fret, the strings are

close but not touching at the first fret with the string depressed at the third fret. Problem is

that the third fret note is about 30 cents high. When I raise the tailpiece to about 1/4" off the

body then retune, the tuning is spot on with no intonation issues at all over the complete

length of the fretboard.

Looking at it mechanically I can't understand any reason for tailpiece placement to affect tuning at all.

The string length between the nut and bridge is unchanged. Bridge height is also untouched.

Any suggestions?

Thanks

Chris

Here's my guitar Crick

Hi, changing the tail piece height will affect tuning, the more you depress it towards the body, the tuning will changes, become sharp, and if you make the tailpiece higher, the strings will become flat. understand?

By moving the tailpiece you are affecting the length of the strings, not by much but enough to change tuning.

[cknowles]

I think I understand.

If I adjust the tailpiece toward the body, I increase string tension and the strings go sharp.

When I retune to a concert pitch, everything should be back to normal.

Intonation at the 12th fret is bang on, however the string tension is still greater since

I've increased the overall length of the string, therefore tuning at lower frets will be out.

Is this correct?

After looking closer at my kit, I am of the impression that the neck pocket is slightly shallow

though the neck angle appears OK. To compensate the bridge and tail piece sit about 1/8" higher

than examples of factory guitars that I've looked at.

At this point I have 2 choices, leave the neck alone and live with the bridge and tailpiece sitting

slightly high, or re-rout the neck joint to make it fit more closely. 3rd option is to build my own

guiter using the kit as a template.

[another doug]

Just throwing things out there:

When the third fret is sharp, are any of the others off that much? Is the first fret in tune? is the twentieth fret in tune? Is it all the strings or just one?

From what I got from your original post, I can't see any reason why any notes would be different if the twelth fret harmonic is still in tune, unless the nut was so high that you had to stretch the string a lot to fret the note (and it sounds like that is not the case).

I believe that the string is at the same tension between the bridge and nut if it is tuned to the same note. However, there was a recent thread discussing the effect of extra string length before the bridge and after the nut. Maybe something to look at, but I think that the change in length lowering the tailpiece would be too small to make a difference (maybe something to do with changing the break angle over the bridge?).

Also, I can't speak for RGman, but it seems to me that he missed the part where you said you retuned after lowering the tailpiece.

Finally, I would like to vote for finishing this project. Even though it's just a saga, any extra work you need to put into it is extra experience going into your next (probably more expensive) projects. All of my projects still need finishing touches that I never got around to before going on to the next one! Don't be like me!

[cknowles]

So far I've tuned the nut so that tuning is almost perfect up the entire neck.

There were 2 frets that were slightly high, and I found that they weren't quite seated

into the fret board, so I carefully pressed them in the rest of the way and all the

frets test level. I have .08" clearance between the 6th string and first fret when

pressing the string down on the 3rd.

To answer your question, the tuning with the tailpiece mounted high is spot on.

Lower the tailpoece then retune and the tuning is spot on at the 12th fret, going sharp as I go down the

neck towards the nut. I can't lower the strings any more at the nut without bottoming out on the frets.

That's what has me baffled.

Before I route the neck pocket, is the fretboard supposed to be raised from the body, or touching it?

[another doug]

Firstly, I hope you meant .008, since .08 is a really big gap! Also, I'm assuming you adjusted the bridge rather than the nut in order to set the intonation.

If the string is in tune at the nut, and at the 12th fret, then all the frets in between should be in tune as well. If one or the other is off, then you have an intonation issue and need to re-adjust the saddle until it is in tune all along the neck. It may be that the extra downward pressure at the bridge has thrown the intonation out of whack.

If the string is in tune at the nut and 12th fret, but not in between, then I'm not sure what that could be. Maybe try a new set of strings?

I don't know enough about the saga lp to know how it is supposed to fit together, but don't assume it is the same as a gibson. You could always try shimming the neck to change the angle in order to set the bridge lower. It's easier than routing, and far more reversible!

Those more experienced than me may have better ideas.

[cknowles]

Wow, thanks for all the help, I really appreciate it.

Yes, .008 my typo (Grin) Bridge adjusted for intomation.

Nut adjusted to fix major tuning issues. Stock nut made the note 1/4 tone sharp.

I used the tutorials at Project Guitar

Your comment about the extra downward pressure makes sense. This isn't a high quality

bridge after all.

I've been doing some more research to find out about the tailpiece/stopbar adjustment.

So far I've acquired the following information (tho I'm not sure of the veracity of all of it):

1. tailpiece/stopbar should not be adjusted so low that strings come in contact with the bridge housing

this will cause string breakage.

2. While there's no general rule for tailpiece height, 1/4-3/8" above the body is in the ballpark.

3. Tailpiece adjustment changes the break angle of the strings over the bridge, and the "feel" of the strings

4. According to Gibson USA

"Adjustable Stopbar Tailpiece. The stopbar tailpiece may be adjusted up

or down to change the downward pressure across the bridge. There is

usually no need to adjust the stopbar unless the strings are moving

out of the saddles, in which case the stopbar should be lowered."

5. I can't wait for that Melvyn Hiscock book to come so I can stop being a pest here

[cknowles]

I don't know enough about the saga lp to know how it is supposed to fit together, but don't assume it is the same as a gibson. You could always try shimming the neck to change the angle in order to set the bridge lower. It's easier than routing, and far more reversible!

Those more experienced than me may have better ideas.

Thanks again, it's one thing to understand these things in theory, a totally other story altogether when

putting them into practice. I've read about string condition and neck angle affecting tuning, but didn't

really understand...now I have a better idea.

I've taken your suggestions seriously.

New strings - somewhat better

Shimmed the neck to change the neck angle, 1/2 of a business card under the edge of the body at the neck

to tilt the neck back. Made all the difference. String action is now at 1/16" with no buz anywhere on any string

over the full neck length. Bridge and tailpiece are now nice and low.

I also discovered that my frets seem to either be pretty tall, or else my acoustic playing style puts too

much tension into the string, I can make everything go sharp just by squeezing. Frets haven't been dressed yet

so that's next, along with replacement of the wiring and adding additional shielding.

Thanks again RGman and "another doug".

I'm learning, and even better having a ton of fun!