Acoustic Guitar - Low Saddle but High Action

[wolfhallow]

I've just swapped out the stock plastic nut and saddle on my Tanglewood Sundance TW45 for bone ones. The new saddle was really high so I sanded it down to lower the action. It was about 6mm on the 12th fret!

After sanding, the hight on the 12th fret is still quite high, around 4mm. However, the saddle now sits so low that I can't sand any more off it and just doesn't look right. Any advice? I want the action lowering but the saddle can't go any lower. The neck seems adjusted correctly as far as I can tell - a slight inward bow with a fraction of movement on the 7th fret.



https://www.dropbox.com/s/ajisqalis6..._9335.jpg?dl=0



https://www.dropbox.com/s/n3v7tn3tj3..._9338.jpg?dl=0



https://www.dropbox.com/s/r85d4b6nps..._9340.jpg?dl=0



https://www.dropbox.com/s/xemym1zm20..._9354.jpg?dl=0

[ChrisN]

What gauge of string on it now? What gauge did it come with new?

Where does 24" straightedge land at/on bridge when laid down fretboard?

Is the heel coming up at all?

I'd dial out almost all of the relief, confirm "light" strings (.12-.52/3), and use the straightedge to the bridge. If it hits below the top of the bridge after the above, it may need a reset, or they installed a too-high bridge at the factory and you could get it shaved down, slot cut deeper. As it is, that saddle's below optimum now, never mind getting the action close to what you want. Something's wrong.

Based on your measurements and photos you have a severely underset neck, at least nothing else in the photos strike me as far out of the norm. The only other thing I'd like to know is the height of the low E string from the top of the guitar, measured from the top of the guitar to the bottom of the string.

You mention swapping the nut, but even that is not setup correctly, it shouldn't create what I'm seeing in the photos and measurements. I assume the action was high before the swap of saddle and nut?

If I'm correct, then nothing other than a neck reset is going to fix your problem. Not sure what that involves on a Tanglewood.

[Wade Hampton]

I agree with Todd, the problem points towards incorrect neck set geometry. Unfortunately, there's no inexpensive DIY remedy for it. It needs a neck reset.

If you bought the guitar new, you should take it back to the retailer and proceed from there. Since it's not a super expensive instrument, it might be simplest to trade it in for a direct replacement.

If they won't agree to that, sometimes you can get away with sanding down the top of the bridge itself so that you can lower the saddle even further. But that's a stopgap measure at best, and really not the best practice.

Hope this helps.


Wade Hampton Miller

[Casey86]

This article in Acoustic Guitar about buying vintage shows how to check if you need a neck reset:

http://acousticguitar.com/how-to-sho...guitar-part-3/

[imc2111]

Couldnt this be the result of high humidity?

[charles Tauber]

Originally Posted by Casey86

This article in Acoustic Guitar about buying vintage shows how to check if you need a neck reset:

http://acousticguitar.com/how-to-sho...guitar-part-3/

From the article:

Of course, over time, strings put lots of tension on a guitar. Certain things are bound to give to that tension, and, as the angle of a neck pulls forward and the slight arch built into a guitar’s back flattens out, you might find that the action gets higher and higher.

The longitudinal arch in the back increases, not decreases, as the entire upper bout rotates "into" the sound hole.

[murrmac123]

Originally Posted by charles Tauber

The longitudinal arch in the back increases, not decreases, as the entire upper bout rotates "into" the sound hole.

You do surprise me, Charles. The convexity increases ?

[LouieAtienza]

Originally Posted by murrmac123

You do surprise me, Charles. The convexity increases ?

I've personally never seen that happen myself on any guitars I've worked on...

[charles Tauber]

Originally Posted by wolfhallow

Any advice?

The bridge appears to be quite thick. It might be an option to shave some of the height off the bridge, allowing more saddle projection.

However, taking appropriate measurements will allow you to determine how much additional lowering of the saddle you want/need. You need 2 mm removed from the saddle for each 1 mm of reduction in string height at the 12th fret. For example, if you want the bass E to be 3/32" (2.4 mm), and you currently have 4 mm, you'll need to remove an additional 3.2 mm. Add in a additional height of the difference between what you have now and what you need to maintain a minimum projection above the saddle, about 1/16" (1.5 mm).

[charles Tauber]

Originally Posted by murrmac123

You do surprise me, Charles. The convexity increases ?

Originally Posted by LouieAtienza

I've personally never seen that happen myself on any guitars I've worked on...

The upper bout rotates, the back curves more along its length while the top goes from flat or slightly convex to concave. Exaggerated, for clarity,




You've never seen this happen, the fingerboard sink into the sound hole and the neck block rotate?

[murrmac123]

I get that the top goes from (slightly) convex, to flat, to (slightly ) concave, due to the rotation of the neck block under string tension , but the rotation of the neck block causes the back to lengthen , surely, and this lengthening has to be accompanied by a corresponding decrease in the amount of longitudinal arch in the back.

Leastways that's how I always understood it.

Originally Posted by charles Tauber

The bridge appears to be quite thick. It might be an option to shave some of the height off the bridge, allowing more saddle projection.

I can't decide if the bridge is thick or just blocky in contour. If the OP can measure from the bottom of the E string to top we'll know more.

On the reasons for a neck reset, I've never liked that particular demo image you posted...knowing that all such images are exaggerated to make a point. To my thinking it demonstrates things that don't happen, specifically the bending of the sides. I don't think they do that, don't think they can. The back flattens a bit, but the bigger change is that the sides fold in a little, not up, and especially in the upper bout. The sound hole creates a weak spot in the top the upper bout folds downward and the lower bout up. That lower bout belly moves the center of the top up, but the sides don't go up too. They fold in.

That might be oversimplified a bit, but it's what I think I see, and can measure sometimes.

[wolfhallow]

Originally Posted by ChrisN

What gauge of string on it now? What gauge did it come with new?

Where does 24" straightedge land at/on bridge when laid down fretboard?

Is the heel coming up at all?

I'd dial out almost all of the relief, confirm "light" strings (.12-.52/3), and use the straightedge to the bridge. If it hits below the top of the bridge after the above, it may need a reset, or they installed a too-high bridge at the factory and you could get it shaved down, slot cut deeper. As it is, that saddle's below optimum now, never mind getting the action close to what you want. Something's wrong.

String gauge is currently .11 - .52. I'm not sure what it came with.

To my eyes the heel looks okay, I don't see anything out of the ordinary, but I'm certainly no expert.

I tried a ruler from the fretboard to the bridge - it fell about 1mm below the bridge.

[wolfhallow]

Originally Posted by Todd Yates

Based on your measurements and photos you have a severely underset neck, at least nothing else in the photos strike me as far out of the norm. The only other thing I'd like to know is the height of the low E string from the top of the guitar, measured from the top of the guitar to the bottom of the string.

You mention swapping the nut, but even that is not setup correctly, it shouldn't create what I'm seeing in the photos and measurements. I assume the action was high before the swap of saddle and nut?

If I'm correct, then nothing other than a neck reset is going to fix your problem. Not sure what that involves on a Tanglewood.

Do you mean the distance from the fretboard to the low E string at the nut end? That measurement is currently 3mm.

The action has always been higher than I'd like, but only now have I actually tried to remedy it. I thought a new nut and saddle would be the first step to making the guitar sounding better, but having assembled these and taken some measurements I realised something wasn't adding up.

A neck reset isn't the news I was hoping for, I didn't realise it could be something so serious. I've had the guitar for 5 years and love it, and have taken really good care of it. The cost of a neck reset would not be worth it in my case!