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I was really happy with how my second build was going. I've got it pretty much done, except for touching up the finish in places, polishing, and filing a bit more on the saddle and nut.

Something must've slipped a little bit when I was gluing the bridge on. I have it strung up with 11's now. When I tune the open strings with my chromatic tuner, and then fret them on the 12th fret, the low-E, A, D, and G are all about +10 cents sharp. The B and the high-E are a little lower than that, and close to being in tune.

I can tweak the saddle just a teeny bit, and get it a little lower, but not much. I've already filed compensation into the top of the saddle. If I were to string up the guitar with 12's, the intonation will be even a little worse, and it may then buzz if I lower the saddle any.

Is this really terribly bad? Is there anything I can do to help out the situation? I have not compensated a nut before. What would that do?

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"...you have to get over your strict adherence to your largely imagined notion of absolute perfection..."

Can you accurately measure where the saddle ended up in relation to the scale length?

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Evan McCartney

Right, that is a good question. It's a Martin 24.9" scale.

Nut to 12th fret is 12 7/16". I doubled that, and intended to add 2mm compensation to the treble side, and 6mm to the bass side of the saddle. But it looks like I somehow fell short between 0.5 and 1 mm on both sides.

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"...you have to get over your strict adherence to your largely imagined notion of absolute perfection..."

That's a wonderful mix of decimal inches, fractional inches and metric there.
You could widen your saddle slot back towards the pins if you need more room.
Working the nut is not the appropriate solution.
Are you down to final height on nut slots and saddle? too high on these will make it play sharp.

Thanks. My string action is still a little high, but not much. What is the best way to widen the slot evenly, once the bridge has already been glued down on the top?

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"...you have to get over your strict adherence to your largely imagined notion of absolute perfection..."

Similar story, working on #2 all is going well, much nicer then the first, until I glued the FB on crooked, about 1 mm off center at the nut, I could have left it but it would make a crooked guitar and I was not down for that much error, so I did my first unglue, took quite a bit of heat from my blanket, but the LMI white did soften, got it off, cleaned and back on, still a bit crooked even with more registration pins, but I can live with this one. Since it is not finished, the remove and replace will take between an hour or two, then it will be right forever, but in the same time, you can make a jig to widen the slot, go with a 3/16 saddle and it will get the intonation better, but to me, removal would be the easiest way to make it right.
Rob

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You need to make some kind of jib to open the slot. If you have a 3/32 saddle going to .125 may help you. I set my saddle .100 on light strings and .125 on mediums to the center of a .100 saddle following the actual string line. I allow another 1/8 " to the bass string. This gets me very good intonation . I have used .125 as requested by customers and this allows a good flexibility for setting intonation.

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

"It's a Martin 24.9" scale. Nut to 12th fret is 12 7/16". "

There's part of your problem: on a 24.9 scale the nut to the twelfth fret is 12.45", not the 12.4375" that you measured. That's about .3mm off to start with.

Regardless of what the scale length was referred to, or mis-referred to, or approximately is, ...measuring nut-to-12th, then doubling it, and adding compensation, is going to be accurate. If it's executed correctly.

Thanks John, jib it is. I'll fix this thing.

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"...you have to get over your strict adherence to your largely imagined notion of absolute perfection..."

Well .. depending what ruler you used to measure, the 12 thou or so that Al is talking about is the width of a line on it .... you probably cant tell one from the other. BTW - your method wont work on my guitars, because I use a compensated nut location - I measure from the 12th fret.

Are the slots machine cut ... or measured and cut by hand ??? Could be an issue.

To widen the slot you need to make a jig to route it wider ... unless you are pretty steady by hand with one ...

Here is something to try .. simply add on some bone to the back of your existing saddle (it will sit on top of the bridge itself, so your saddle is now kinda upside down L shaped) .. crazy glue it on there .. now reshape the saddle crown, and see if that helps. Figure out how much wider the slot needs to be this way.

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

I like that L-shaped saddle idea, thanks!

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"...you have to get over your strict adherence to your largely imagined notion of absolute perfection..."

Yep .. it works ..had to have one on my first way back when, before I redid the whole bridge, but I needed it to go forward about 2mm ...

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Do try lowering the action first, it may get you just enough

Tony that is a cunning plan right there.!
I recently did a sharpy by filling the existing slot with RW
and rerouting,as I was not interested in removing on that particular guitar
Its virtually invisible in the shadow if the new saddle and under the strings.

I did the same thing on my second guitar, which was a real drag as the guitar had turned out remarkably well. Couldn't believe it when I found my error. I brainstormed all kinds of fixes, but in the end I decided to go ahead and remove the bridge and replace it in the proper position. Of course that required a host of other steps and proved to be quite an interesting and educational undertaking. Faced with the same situation again, I would first try either widening the existing slot or filling it and re-routing.

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George :-)

Over the weekend, I removed strings and worked on the saddle. I lowered the top of the saddle between 1/32" and 1/16", and angled the top of the saddle so that the peak was near (or on) the back of the saddle for all strings, and strung it up with 11's. This helped everything out, much more than I anticipated it would. It's now very very close to being dead on. Only one string, curiously, the 'A' is out when fretted on upper frets, by about 5 cents. I'm wondering if maybe it's because that string got unevenly stretched or something?

I don't like it that 12's will be farther out, of course. But the friend I built this for, says he will prefer to always use 11's anyway. I also don't like it that the saddle peaks are on the back of the saddle and not the middle.

the saddle slot is 3/32. I have a couple of weeks before I give the guitar to the friend I built it for. I can build a jig to widen the slot, and make a new saddle, or I can let it go.

I often like to ask myself: What Would Jimi Do?

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"...you have to get over your strict adherence to your largely imagined notion of absolute perfection..."

Here's how it looked and sounded as of last night. Thanks for the input so far, everybody.

http://www.youtube.com/watch?v=y8PRP9IKmGQ

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"...you have to get over your strict adherence to your largely imagined notion of absolute perfection..."

Finally fixed the problem once and for all last night. I built a saddle slot jig and used a Whiteside 1/8" spiral downcut bit. My intention was to add 1/32" to the back of the saddle, but it was hard to get the bit to be exactly right up against the front of the slot. My line was even, but I added a touch more than 1/32". Oh well, it sounds good now.

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"...you have to get over your strict adherence to your largely imagined notion of absolute perfection..."