A question for the builders

[TEK]

I am a hobby builder and have picked up about everything I know about building here on this forum. Thanks to everyone who contribute.
I put a 25' radius on my tops and brace in a radius dish. I also contour my rims with the same radius dish by "driving the bus" (spinning the dish on the rims)
When bracing the top I put very little if any radius on the UTB to keep that part of the top fairly flat. My problem is the fall away the top has on it at the neck joint created by the radius dish . It always leaves a small gap just under the finger board extension right at the joint. I do sand where the extension will be glued to make it flat, but I don't want to make the soundboard too thin there. This part has always left me scratching my head about using the dish to put the radius on the rims because it will always leave that part slightly lower.
What am I missing ?
Is there something you use to fill that small gap?
See picture below.
Thanks in advance.
Travis

[Halcyon/Tinker]

Well, for one, 15' on the top is pretty tight. Not a lot if folks do that, I don't think. Nothing inherently right or wrong about it if it's by design and intent, but it's a bit of an outlier. More common is a 25-50' range.

Anyway, it looks like you need to sand a flat spot into the rims themselves. John Hall of Blues Creek guitars has some tutorials that could explain it better than I could through text...

[Halcyon/Tinker]

Nice clean work btw!

[TEK]

Originally Posted by Halcyon/Tinker

Well, for one, 15' on the top is pretty tight. Not a lot if folks do that, I don't think. Nothing inherently right or wrong about it if it's by design and intent, but it's a bit of an outlier. More common is a 25-50' range.

Anyway, it looks like you need to sand a flat spot into the rims themselves. John Hall of Blues Creek guitars has some tutorials that could explain it better than I could through text...

A proof reader I am not. That was supposed to be 25'. I changed it now. Thanks.

[John Arnold]

The choices are to taper the fingerboard itself or to install a shim. A shim is easier, and a matching color won't catch the eye when the edge of the fingerboard is dark (as in this case). But if the neck is bound with white, ivoroid, or light-colored wood, I don't recommend a shim.
I would not sand the top to level it. I want the top to be full thickness in that area.

[Alan Carruth]

I radius the UTB as well, and have been using shims for a long time as the easiest and least obtrusive way to get the fingerboard and top to match up. I generally use the same wood as the neck. If it's well done you get few comments.

[TEK]

Thanks John and Alan for the suggestion. I will work on a shim.
For builds here on out it makes sense to sand the radius into the rims and then go back and sand in the correct angle for the neck/finger board at the neck block so that I do not get the drop off at the edge of the top. It is such a small amount that it should not take much but will look sooo much better.
Travis

[Halcyon/Tinker]

FWIW, yours is a standard problem for which a fix has been found...

[TEK]

Originally Posted by Halcyon/Tinker

FWIW, yours is a standard problem for which a fix has been found...

Thanks, your making me feel much better. I am self taught by following along build threads and reading what I can but sometimes the obvious is not so obvious. There is more to building than most people think.
Still having fun
Travis

[redir]

That's a great looking guitar.

That's not what people typically refer to as 'fall away.' In fact it's quite the opposite. I don't see why a shim would not work there but usually the problem people have is that they have a gap at the very end of the fret board where the sound hole is. Some people will just glue it down but then you get excessive fall away and I think it causes the dreaded body joint hump too. So a shim there accounts for the gap as well.

I don't use a radius dish but I think if I did then after I was done driving the bus I would then take it to a flat sanding board and just get that upper bout from the sound hole forward nice and flat and set to the right angle.

[TEK]

Originally Posted by redir

That's a great looking guitar.

That's not what people typically refer to as 'fall away.' In fact it's quite the opposite. I don't see why a shim would not work there but usually the problem people have is that they have a gap at the very end of the fret board where the sound hole is. Some people will just glue it down but then you get excessive fall away and I think it causes the dreaded body joint hump too. So a shim there accounts for the gap as well.

I don't use a radius dish but I think if I did then after I was done driving the bus I would then take it to a flat sanding board and just get that upper bout from the sound hole forward nice and flat and set to the right angle.

Thanks Redir,
That is my plan from here out, just had not seen where anyone showed doing it after the radius dish sanding.
Travis

[nacluth]

Typically we fit this joint perfectly before finish is applied to make it easier. We have no qualms about flattening out the area north of the soundhole to get the radius to fit the neck angle tight. The transverse brace and the heel block (especially if it has a corresponding block under the fingerboard) lend a lot of support to the area. It should be ok to take some meat out of to get it close. Shims work too of course.

[SnowManSnow]

I'm FAR from a "builder" I suppose, however let me suggest watching John Hall's Video on preparing the rims. What he does is, after putting the 25' on the top, flip the dish OVER onto the flat side and then press down on the top so that it is only sanding the area in question. There should be a gap at the lower bout between the dish and the wood as you press down to sand the upper area. Sand that area flat back and forth to remove the radius of ONLY that area.

HOWEVER, even after that is done, you're likely going to have a gap between the fingerboard and the top because the neck is leaning back at an angle and the finger board continues that angle over a flat area in the top. So, you'll need to adopt a method for projecting that into the shape of where the neck meets.

Again I'm new myself, only on my 3rd build, but these issues also plague me


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[SnowManSnow]

I'll do the leg work for ya here is the John Hall video and ONE way of setting the angle


Prepping rims with dishes
https://youtu.be/LrgRKKsxL-M


Neck set
http://kennethmichaelguitars.com/NECKSET.html


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[TEK]

Originally Posted by nacluth

Typically we fit this joint perfectly before finish is applied to make it easier. We have no qualms about flattening out the area north of the soundhole to get the radius to fit the neck angle tight. The transverse brace and the heel block (especially if it has a corresponding block under the fingerboard) lend a lot of support to the area. It should be ok to take some meat out of to get it close. Shims work too of course.

Thanks Ryan,
obviously I am too far on this build to do anything except a shim but I will make it a point on the next to make adjustments before the top goes on.

[QUOTE=SnowManSnow;5328296]I'll do the leg work for ya here is the John Hall video and ONE way of setting the angle


Prepping rims with dishes
https://youtu.be/LrgRKKsxL-M


Neck set
http://kennethmichaelguitars.com/NECKSET.html


Thanks Snowman for the links, I had watched Johns video a year ago but it was very early on and not sure it sunk in. At least not the important part of it.

I did make a shim last night and after got the neck glued on and it looks fine.
I was mainly curious more about weather builders addressed this issue before the top went on, by sanding off the area a little flatter or if they addressed it after the top was on by sanding the top flat. From here on out I will be addressing it before the top goes on.
I was concerned that if it were the later, the top would be very thin in that area.
I do build with a piece on the top of the neck block that also connects with the UTB so the thin top should not be a issue.
Thanks to all
Travis