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Getting closer and closer to finishing my first. After I put the frets in the other day I decided to should probably look at how things were shaping up with regards to string action.

Note that I haven't glued the bridge on yet, and this measurement is without the nut and the saddle.

I placed my long ruler on edge, sitting on the nut end of the fingerboard, and the bridge saddle slot. This is what it looks like.



That distance at the 19th fret from fingerboard to ruler is about 7.5 mm. I believe this is way too high, especially considering its only going to get higher once the nut and saddle are on. I should mention that this is a classical.

If this is a problem, what are my options? The only thing I could think of short of ripping off the fingerboard and putting on a new one is to rip the frets out and shave off a few mms at the nut end of the fingerboard. Dunno how much that would really help though.

Before I glued on the fingerboard I had tapered it from the nut to the 19th fret end like Cumpiano says (following his book), so that its maybe 1.5mm flatter at the 19th fret. Apparently because of the angle in my guitar that's already there, this may not have been necessary?

Looks a little like your neck angle is too steep. How thick is the fingerboard, and how tall is your bridge at the saddle slot? Is the fingerboard tapered at all? Is the top domed, if so, how much?

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Waddy

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Heya Waddy, the fingerboard is real close to 7mm (6.7mm?) at the nut, tapered down to 5.5mm at the 19th fret. The bridge at the saddle slot is 10mm. The top is domed, but I have no idea by how much. I didn't have any good way of measuring that, I just curved the braces how much I thought they should be curved and went with it heh.

You really needed to plan all this in advance carefully If you have that much of a gap just resting on the ebony and bridge, it will become even higher with the bones in place - either way it is completely unplayable.

What is the thickness of the bridge right now? You will need to plane it down as much as possible that will lover thing some. You can go down a lot, final thickness of 6-7mm. If it is your first it might be much taller than needed.

You also need to pull the frets and plane the front of the FB and make it at least an even height across the length. A slight back taper can be acceptable too, it is better than an unplayable guitar.
I really hope you did not carve the neck yet...you should not carve it until the string geometry is right...

Tell us about the bridge dimensions and current full neck thickness and we can do some rough math.

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Now I saw, 10mm, that is huge. The standard bridge height is about 8-8.5 mm.

Please measure the current neck thickness.

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Matt,
First, If you could tell us the distance measurement from the top of the fret to the straight edge at the <12th fret> it would be much more useful in determining the extent of the adjustment needed.
I concur with a bridge height of around 8 mm (minus saddle) though you could even go lower if neccessary.
You may have a problem in that your string holes may not give you enough break over the saddle once the height is taken down. An 18 hole bridge might help with this.

Meanwhile what's that measurement?

The bridge at the saddle slot is actually closer 9mm, I measured again today. That's right at 3/8ths, which is the height suggested by Cumpiano. I am however using the Bouchet 1969 plan, and while I am unsure by looking at the drawing how high it wants it, it is either 11mm or 8mm. I guess that extra thing on the drawing must be the saddle, hard to tell. If that's the case then 8mm is what it calls for, so im not far off on that. I could take 1mm off too.

David, the distance from the top of the 12th fret to the straightedge is 5mm.

I have already shaped the neck, going by the Bouchet plans it is 22.8mm at the nut going to 23.5mm at the 6th fret.

Matt-
You have some expert help here, so I will not chime in with any recommendations.

I've had to wrestle with some of these problems (hasn't everybody?). One thing to remember is that to make a change of 1mm at the 12th, you need to make a 2mm change at the bridge. So if you have 3mm of saddle projection above the bridge, that will raise the straightedge at the 12th by 1.5 mm, etc...

Can you measure the amount of 'dome' in the top, just for reference for the rest of us? Thanks.

John

This is a classical???

Yes.
1969 Bouchet

Whatever plan you use, you do not need a bridge taller than 8.5mm, so what you see there must be with the saddle. 10-12mm is the normal string height for a classical.
22.8 at the first fret is a thick uncomfortable neck for lots of people. You can go as low as 21-21.5 mm without problems. Bridge height can be as low as 7mm. Whatever change you make at the nut or saddle, it will translate into a half of it at the 12. The 12th fret action you want is 4mm from fret to straight edge. Don't worry about the 19th. You also want at least a couple mm of saddle sticking out of the bridge.
Start by refining down the bridge and keep the refret as a last resort.

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Thanks for the suggestions all. Being my first I generally have no idea what I need to be looking out for as I go, I just try to follow Cumpiano.

Anyway, the arch of the top at the bridge is real close to 3mm. Is that about right? I completely freehanded the arch in the braces, just did what looked best since I didn't have a radius dish or anything, so that's always been one big question mark for me.

If I have 5mm at the 12th fret right now and I take 2mm off at the saddle slot... hmm well I guess I would have to take 3 off and have 1mm of saddle sticking up... that would give about 4mm at the 12th based on what you were all saying. Would that be in a good range?

Oh and by the way here is a shot of the line along the fingerboard where it intersects with the top.

Sounds about right, but it might be good to plane about 1.5mm off the nut end of the FB too and end up with a more normal bridge and saddle height. It is really no big deal to pull the frets, just heat them well first.

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I guess I would need to buy some fret pullers? Or are there less expensive options?

Question about planing ebony. When I tapered the fingerboard in the first place (I guess I shouldn't have!) I tried to use my low angle block plane and had a heck of a time. It was real sharp, but I really struggled and never was able to get nice smooth shavings. Is another type of plane recommended for ebony? I don't know jack about planes! (pun intended!!) hehe

Maybe I should just use my scraper....

That would also mean I would need to buy a fret saw to deepen the cuts for the frets.. (it was pre-slotted for me).
crud

Ouch that looks very steep. UN-fretted, you want the straight edge to kiss the bridge somewhere between 1/3 and 1/2 of the bridge height. Add 1mm when fretted. This is ideally, for your next one, as you will not have enough nut meat to plane that much with this one.


Planing ebony is can be easy and fun (or at leats my idea of fun) but a block plane is a bit too light. The heft of a Jack plane helps a lot but most important is to be real sharp. It is real sharp when it shaves your arm with ease, or splits paper with ease (this is the Japanese check, when you run out of hairs). Don't forget to hold the plane at an angle to the length of the board, cuts easier.

And then after just a few minutes of work you need to sharpen again. Anyway, I would not try to change the FB angle with just a block plane really...

For pulling I use the same LMI flush cut pliers I use for cutting the frets.

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Ok so where did this mistake originate do you think? The angle of the headblock where I glued the top on? It seemed straight when I glued the top on.

Wha is critically important is the neck angle when you glue the back on. This sets the angle of the neck.
Since it appears you have not bound the edges yet it may be worth removing the back (in the upper bout)to readjust the angle.

Its bound already actually.

I don't understand how the back affects the angle between the neck and the top...

I see the binding now on your second photo didnt look like it was bound on the first.
The neck /top sides assembly are quite flexible until you glue on the back, you can move the nut end forwards or back to give the required neck angle(slightly distorting the rims)
Once you glue on the back it locks the neck in position.
Your neck is way too far forward and I doubt that even replaning the fretboard and lowering the bridge will get you to normal action.
Do the numbers, Your straight edge looks to be hitting below the base of the the bridge(1mm below. Add 10mm minimum for bridge and saddle gives 11mm above the fretboard plane. This implies a 5.5mm string height at the 12th fret or more if the top comes up a little when strung to tension.

I would think your options are to loosen the back and reset the neck angle or to build a new fretboard, which would need to be very thick at the soundhole end.

Hi Matt: Unfortunately, Cumpiano doesn't discuss neck angle (rake), but had you followed his text "to the letter", you would have ended up with a proper action. I think where you went wrong is in how you domed the top. Following Cumpiano's method of using a 1/8" spacer aroound the rim of the body on the solera and a similar spacer under the neck, you should have a maximum of 1/8" dome -- and yours appears to be more than double that. In fact, as Jeff replied, you can increase or decrease the neck angle, so that when you glue the back in place, the angle is locked. If you were to remove the back, and place a shim at the nut end of the solera to increase the neck angle, you could reglue the back and have a little extra wood to trim off (more difficult to do this if the neck angle had to decrease). I would remove the back, by routing out the bindings, and using heat to soften the glue and a palette knife to separate the back. Add a shim to increase the neck angle, and reassemble.

Question remains, how do you know how big a shim? Actually easy to calculate (my measurements given are all hypothetical -- use your own).

First, calculate the string height at the bridge "above" the plane of the solera neck surface at the body joint by adding up: Bridge height (7.5 mm) + saddle height (2.5 mm) + top dome (3 mm) + neck rise under tension (0 mm for classical) = 13 mm

Second, calculate how high we want the strings above the neck at the body joint (12th fret = half scale): Fingerboard thickness (6mm assuming equal along length) + fret height (0.75 mm) + desired action above fret (3mm) = 9.75 mm.

So, we want to shim the neck angle so that the nut end is 13-9.75 = 3.25 mm above the solera.

Planing the fingerboard is an option, but only if you have enough "meat" to thin the nut-end by the amount of the calculated shim. I think you're probably well short of that.

Ummm....

Oft the thing on some slide player and go build another one, only pay a bit more
attention to the neck angle.


Padma

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Yeah that's true heh.

I didn't even use a proper solera, just a flat board with some carpet on it and some cardboard around the edges, but as I mentioned before, the dome is 3mm, so I think that's correct.

Tim if I understand correctly what you are saying basically is that if I put a shim at the nut and then press down at the 12th fret with the back off, that should push the angle into a correct orientation? I am trying to think about what that will do to the sides... hmm. You think the back will still fit? I guess ill have to remove the fingerboard as well. Man I wish I had understood to check all this before I shaped the neck and put the fingerboard on.

And thinking about routing off the binding with all the problems I had routing those ledges in the first place sure makes me kinda sick lol.

Guess I can have Grant bend me some more and send em....

These things aint free and im a poor college student! I'm already breaking the bank with just one hehe.

Ummm....

Oft the thing on some slide player and go build another one, only pay a bit more
attention to the neck angle.


Padma

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Audiences and dispensations on Thursdays ~ by appointment only.


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I'm with Tim on this... got nothing to loose

Jeff