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Hello all,

While I have built a large number of the steel string guitar, I am now building a Classical (my first one) and I think I have screwed up and I need some input.

I thought I had the geometry figured out but it looks like - probably not and I wanted to get some opinions of what to do.

The top is domed (50' radius all over). The neck was glued on (dovetail) with slight negative angle to counteract the upper bout dome - I tapered the fingerboard over the body to match the dome and slight negative neck angle (very slight).. The fingerboard was glued on in a fretted state (this is how I do my other guitars).

Here's the deal: With a 12.5mm bridge height (total with saddle measured off the soundboard in front of the saddle) - measuring off of the second fret (this guitar has a Zero-fret, no nut - it's a Maccaferri Classical) and the bridge I get 1.75mm action @ the 12th fret. I measured off of the second fret as my accurate straight edge is only that long..

My questions are the following: Given the neck will bend under string tension (has 3/8" x 1/4" carbon reinforcement in European Walnut neck with 6.5mm ebony fingerboard, 22mm thick at 1st fret, 24 at 8th fret) and the top will belly some (I am guessing this is a medium strength top/bracing), what can I expect the action to rise? Can the bridge be brought any higher without everything going to hell in a hand basket?

Of course I don't want to rip the fingerboard off but I certainly if I have to.. I could taper it's thickness a bit if necessary to get the bridge down / action higher..

Any thoughts?

Thank you, Peter

I always thought Classicals had a Positive Neck angle i.e. the fretboard crashes into the soundboard.

Anyway. Stick a standard veneer (0.5mm's) on top of your second fret. That will (roughly but near enough) give you the real world distance. Then measure your 12 th fret action. Your Neck will barely move. I haven't been able to measure more than 0.2 mm under string tension and even over a long period of time it can be very little. That's using Cedrela without any reinforcement. Mahogany can be even less. You won't get much in the way of action change. I'd forget about it as being a factor. I think your under where you need to be.

Or you could try this method: Place a straight edge on top of the frets and measure the distance between the soundboard and straightedge at the saddle position. It should be close to 4 mm's. My saddle height is at 12 mm's - slightly lower than yours.
You can make a straightedge from a fairly well behaved piece of wood. Doesn't have to be precision engineered, just good enough.

I agree you don't get much movement when strung to pitch but it depends on how light your top is. How much saddle is sticking out? Everything depends on your design but my classical guitars are built so the neck angle is flat right off the sound board and then I taper the fretboard as necessary to get the desired action then fret it. It depends on the player of course but typically the action on a classical is much higher then on steel. If your fret board is thick enough you may be able to get away with a refret and resurfacing to get a bit more action.

That is the method to apply. You want to have a string eight at the bridge of around 9 to 12 mm. (I try to be closer to 9.) So if you want an action of, say, 3.5 mm at the 6th string, than you need to double that and add it to you straitedge measurment. Relief will add an insignificant amount to string height.

So :7 mm (twice the action) + 4 mm (straitedge mesurment) = 11 mm string height.

All this to say, you won't have much choice but to pull your fretboard and tapper it. I think your initial mistake was to give a negative angle to your neck.

_________________
Alain Moisan
Former full time builder of Acoustics, Classicals and Flamencos.
(Now building just for fun!)

Ok, off the finger board comes!

By negative neck angle - I mean the plane fingerboard intersects the plane of the soundboard (crashes into it).. Unfortunately, my angle was too slight, so that what I was attempting to do to get the geometry correct.. well I didn't do it.

Live and learn..

Thanks, Peter

I was always led to believe that SS had a negative angle, Classical a positive. Maybe I have it the wrong way around.

At least you have a dovetail joint! relatively easy to take off. One of the easier ways to test your neck angle whilst fitting is spot glue 2 softwood blocks, one at fret 1 the other at or near fret 12. Make them the height of your fretboard + fret height + string distance (fret 1, usually near to 8 mm's) and fretboard + fret height + desired action (fret 12, near to 11 mm's). Read your saddle distance from the straightedge. That's before fretboard is glued of course.

Yes, good point. Although you may have to deepen the fret slots near the soundhole if they are not deep enough after you induce the taper. If your fretboard is binded, it might be a pain. If not, than it is a much easier job than to remove the fingerboard.

_________________
Alain Moisan
Former full time builder of Acoustics, Classicals and Flamencos.
(Now building just for fun!)

Been there!

I have found that a quick way of getting your neck angle into the right neighbourhood is to add the amount of doming measured at the bridge with the amount of neck angle measured at the nut. If they add up to 5mm then you'll be OK with about 10mm string height at the saddle. This is close enough to make fine adjustments by shaping the saddle.

Looking forward to the results of your Maccaferri classical. I've been interested in trying one out for awhile. Did you include the internal resonator?

_________________
Expectation is the source of all misery; comparison the thief of joy.
http://redrivercanoe.ca/

I have already taken the fingerboard off the guitar. I tapered a fingerboard quite heavily. Things are much better, but it looks like to get the proper action the bridge is going to need to stay where it was before.. 12.5mm (total height with saddle). Is this workable or just too dang high? If not, the neck will have to come off.. I really don't want to do that unless you guys say I have to.. then I will bite my lip and do it....

Douglas Ingram: No internal resonator this time. I have had a couple original Maccaferri's open at times to see the resonators. They were pretty neat and incredibly well executed whether or not they did much. I have played one with an intact resonator and it sounded great, but it may have sounded great without it as well.. From what I have read, the real advantage is that the resonator made the notes more even.. sort of like a compressor. There are a LOT of pieces to the resonator and it would be fairly complicated to build. It is suspended from the top - right at the sides and there is certainly lots of room for error. If something got screwed up or damaged, it would take a miracle to be able to fix it without disassembling the guitar.

John Monteleone (of arch top fame) made a bunch of these under the guidance of the man himself back in the 80's before Mario died - they were friends and from what I understand, John very much admired Marios work. They made a bunch of the Classical's with differing resonators and a bunch without. They said the best one from those batches happened to NOT have a resonator.

Anyway, this is my first stab at the nylon Maccaferri. I have made a large number of the steel string ones but this is a different beast entirely.. Although the body (minus the top) is exactly the same on the steel strings and the nylon strings.. They all started out as Nylon string guitars and then the designs were modified into steel string models.. The body stayed the same though. Kinda neat.

Mario Maccaferri worked under Luigi Mozzanni who was quite brilliant.. The both of them were as far as I am concerned.. If you look at their early stuff you will find the precursor to the Millennium (type) guitar, the modern sealed tuning machine, the cutaway (compound even- tapered and flush with the heel) Cool harp guitars, etc.. All this before 1932. Some of it well before that.. Both Mario Maccaferri and Luigi Mozzani were Classical Guitarists (performers).

Anyway, thank you all so much for your help up to this point. It has been great. Hopefully this guitar won't die on the launch-pad..

Thanks, Peter

12.5 mm is a little on the high side but I don't think it is worth it to take off the neck for that.

_________________
Alain Moisan
Former full time builder of Acoustics, Classicals and Flamencos.
(Now building just for fun!)

Does this have a floating bridge/ tailpiece (macaferri)
If so 12.5mm is certainly not a problem, could go higher

No this is a straight-up classical nylon string guitar with a standard classical bridge/tailpice. Only the steel string Maccaferri's had floating bridges and tailpieces, the nylon string ones were of fairly traditional classical design.. fairly.

Peter

Leave it at 12.5 mm's. Might take some time but It will only ever go lower.

What is your fretboard thickness at the nut? I was just wondering if you had enough to play with to start out when you began tapering. I usually have 7mm of fretboard at the nut end. With the usual forward pitch of the neck, I usually take off at least a mm tapered from the 12th fret to the soundhole on the bottom side of the fretboard.

I always fret mine last so all this stuff can get checked and rechecked a billion times before the fret go on - particularly since I tend to relieve the bass side some from the 6th or 7th fret onward for the extra string motion, plus taper from the treble to bass side as well so I can get an extra mm of action on the bass side without extra string height at the saddle.

_________________
Jim Kirby
kirby@udel.edu

I think he stated 6.5 mm's with the original intention of no taper, cranking the Neck forward so that it effectively crashes into the soundboard. It's the method that I use and in the past I too have done it wrong. . . probably most of us have at sometime.
You live and you hopefully learn.

I got it sorted out and playable! Thank you all for everybody's advice. This is the most help I have gotten from the forum thus far. Without it I would have been sunk. I got the geometry sorted. The geometry actually turned out better than I thought it was going to be and as the top and neck settle in I bet I'll be able to take the saddle down a wee bit more. Thanks again for everybody's help.. This is my first Nylon-Strung guitar but it sounds great to my ears and I am really excited to make more of them.. What a learning experience!

Cheers, Peter