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I have read how important it is to get the angle of the upper bout correct as it meets the neck attachment area and I think I see why now.

In order to get the fretboard to lie flat on the fretboard extension area the angle it creates is too steep and will cause that angle to meet the bridge too high.

What is the solution? I don't want to alter the angle of the underside of the fretboard as it will be laminated with w/b/w veneer and I don't want a huge bridge. And sanding the are of the upper bout seems extreme and that would effect the rosette as well. Help?
Bad drawing to follow.

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Thanks very much Hesh and I can now why the flat upper transverse brace and the reason behind your method, which Iread a dozen times before but never really got it.

Mine UTB is radiused and I can see the problem now as the fretboard wants to ride up the angle created by the radiused UTB.

I have not glued on the fretboard and am just beginning to trial fit the neck. I also have fit a couple of other necks but with limited success so I want this to be right.

I know how to adjust the neck angle to bring down the angle and meet the bridge but that would require the fretboard no longer matching the angle created along the upper bout at the neck attachment point. It would actually create a small gap where the angle changed or of course the 14th fret hump, only in this case it would be the 12th fret.

I can't really sand the top thinner under the fretboard extension as my rosette is already crying from being too thin.

I can fake it just fine but am tired of faking it and am now learning how important the neck and angle is to a finished guitar's playability. Just a bit stumped as to the next step.

Should I sand the bottom of the fret board at the angle change? That cannot be smart me thinks.

Hmmm... putting brain to work...still thinking...

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I just had a thought (really miss that edit button), it seems that the problem is even worse with a 12 fretter since another 2 frets worth of fretboard need to be messed with. Can I go back and redo the top?

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Thank You and Best To All

I also create a flat upper bout but Lance and others use a sanding stick that flattens out the upper bout area where the fb gets glued. Using that, it would seem that you could get closer to the plane that you need and the rosette should not be affected.

Hopefully Lance will chime in and post a pic of his process. I would avoid tapering the fb if at all possible.

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JJ
Napa, CA
http://www.DonohueGuitars.com

Thanks you guys, very much appreciated. I will measure the distance tomorrow Hesh as I'm about done for the evening and I'll check to see what the height above the bridge(at 3/8") might be. It seemed to me it was perhaps 1/8 - 3/16 of an inch. A long way to my mind. And getting the FB to dive after the body will only mask the problem it seems? Wouldn't that still require a very high bridge or saddle?

I haven't yet carved my bridge's final profile so perhaps a thicker bridge?

JJ thanks for the help but I cannot imagine trying to flatten the upper bout in the area and not affect the rosette. The rosette actually defines the highest part of that region so any sanding would affect it for sure. How much and how badly is the question. I'll have to see if there is any room to drop it a bit.

Another challenge is that I will(for the third time) laminate a w/b/w veneer on the bottom of the fretboard to carry the w/b/w theme throughout this build so any tapering of the fretboard would have to be done prior to that lamination and then glued/clamped in a way to preserve that taper. Sounds like it has the potential to end up worse than it is now.

Could try and take some off the top of the fretboard but I don't think there is enough room to drop it from there.

I'll work on it a bit tomorrow and post a solution if one comes to me.

Good night all and thanks again

larry

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I do it a completely different way than the others and this may work in your situation. First off I radius all braces and the rim and everything.
I then have some measuring to do coupled with some desired thicknesses.
Here's an example of how I do it. actual numbers will vary for each instrument and the desired result, so don't use my numbers, your's will be close I'm sure however.

bridge thickness - .345 (Theoretical in my case)
Fret board thickness - .230 (actual in this case)
fret height - .050 (actual)
saddle height sticking out of bridge - .050 (theoretical depending on end set up, top flexibility etc..)

so with these numbers the air gap between the bridge location and the plane of the bottom of the fingerboard whould be: (bridge thickness + saddle hieght)- (finger board thickness + fret hieght) or .395-.280 = .115

I then make a shim .115 thick and tape it at the location of the saddle and then use a sanding board to create a flat that just lies under the finger board, This flat should be no wider than the finger board. Since you sanding a dome the area under the finger board comes of first. There's usually not much material to remove and it goes really quick.

I hope this makes sense and it has worked well for me. I've had better results this way that building part of the top flat and part radiused, I've done that too, I now prefer this way but many like the other way. I think which ever way your most comfortable with in the long run is the right way.

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Jim Watts
http://jameswattsguitars.com

Terry post while I was typing, but I think what I've tried to describe is similar to the "fox paddle" or Lances jig.

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Jim Watts
http://jameswattsguitars.com

I have pretty much eliminated the need for using that slick little paddle board, which by the way I got the idea off if Michael Greenfields website, check it out if you haven't, he has some great pictures there!

I now do more like Hesh, flatten the upper bout from the waist to the neck block, then after the top is glued up, I use a large flat sanding block to true it up.

Here is a pictures which clearly shows the sanded flat area.



By the way, I first learned of the flattened upper bout from Hank Mauel while working on the 13th fret OM project, He is full of stuff like this!

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Lance@LuthiersForum.com

Lance's pic shows exactly what I was referring to...the rosette is relatvely unaffected.

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JJ
Napa, CA
http://www.DonohueGuitars.com

OK I'm getting a much clearer picture of how to proceed and I'll try sanding the area flat.

In my case though the rosette IS the high spot. It will have to be affected in some way as I try and lower that area.

I'll check it in about anhour after a cup of coffee and a cruise through the OLF.

Thanks very much

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Thank You and Best To All

Lance: to double-check: you radius the top rim to 25', then flatten everything behind the soundhole (introducing an angle, but getting rid of the arch), and gluing the upper transverse flat? Or is that still radiussed to match?

Hi Mattia,

Yes, and no, I radius the entire rim to 30', then add kerfing, then flatten the area from the neck block to the rosette using the back of my radius dish, just like Hesh. The top has a flat traverse brace, glued on once again using the back side or flat side of the dish, all other braces are radiused to 30' and glued in the dish.
Then I glue the top down. At this point I use to use that paddle board jig, but with the 30' radius there is even less to flatten so I use a sanding board that is maybe 10" X 4" and flatten the area out. Usually not to much to sand off since it was glued on pretty flat to begin with.
I'm not sure if I'm talking in circles or not?

Hope this helps.

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Lance@LuthiersForum.com

Here's what I discovered. This being my first rosette I made a complete mess of the area under the fretboard and didn't really care because it would be covered up.

What I ALSO did was not scrape or sand that area AT ALL which actually created a high spot RIGHT UNDER the fret board extension. A little sanding was all it took and I think I even have a little more room if necessary. Need to trim the cheeks of the neck to change its angle and it should be good to go.

I was very surprised at how little material had to come off to make a big difference.

Thanks SO much for all your help.

Larry

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Sweet Success!

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Lance@LuthiersForum.com

Lance: thanks, makes perfect sense. Pretty much what I thought, may have to give it a try!

[QUOTE=LanceK]Hi Mattia,
. "The top has a flat traverse brace, glued on once again using the back side or flat side of the dish, all other braces are radiused to 30' and glued in the dish.
Then I glue the top down. "

Sorry this maybe dumb question, but I hopefully will be coming up to this stage shortly...

When you do this , I'm thinking I can't use the radius dish as a base for glueing on the top in my go bar deck because the top does not have the consistant radius ( 25' in the case of my dish.) Is that correct?  Thanks..

Thanks Hesh..Perfect! Thanks for the description ..and great photo!

 

Irwin