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Im not so sure that the broken kerfed lining is a big deal, especially considering some people glue individual blocks in place. I could be wrong though.

Ok, so I was thinking about the process a little more. So because you have to bend the back a bit to conform to the lengthwise arch created in the sides, this in turn should flatten the back out slighty shouldn't it? That could be the reason for the heavy initial curve of the back braces.

thanks for reply, Todd. So, do you glue the kerfed lining on before tapering the back? And so the kerfed linings become reduced in size as they reach the head block.

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We are all in the gutter but some of us are looking at guitars.

I could be wrong but I don't think that is what he was saying and if I remember the Cumpiano/Natelson method correctly the sides are bent at full width across the lengthe of the board so you really cannot glue the linings in first. I use a similiar method and get everything close then glue the linings in and finish it off. That bend at the waist you are talking about is no big deal with normal kerfing it just goes with the flow. I have no experience with reversed linings though.

Yeah, on my build I cut the kerfed linings at the waist and glued in the next strip at the new angle.
Wasn't sure if that's the best method but how else to get a straight strip around a curved rim? Your method of making the kerfed linings wide is good also, Todd. Might try next time.
Anthony, sorry for ignoring your original post and butting in with my own problems.

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We are all in the gutter but some of us are looking at guitars.

AnthonyE, thank you for the thread! There were a lot of questions I had that I got answered here. I appreciate all those who responded with their experience and knowledge.
I was talking with someone else on another forum and mentioned how amazed I am at the willingness of most builders to share and to help. So glad to be a part of this community, and hope I have plenty of opportunity to pay it forward in time.
The only negative is that now I have clamp envy, lol.

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Mike

The only thing nescessary for evil to thrive is for good men to do nothing.

Cumpiano does things the way he does for two reasons:

1) It's the method he was taught and, where he thinks it was deficient he's made some changes.

2) He enjoys the process.

For instance, he was taught to rope the back to clamp it.

I told him I had a crap load of clamps and he said that would be fine if I could clamp them fast enough, so that's what I do, and I actually like manipulating clamps and finding their optimum positions. (I'm quite good at clamping broken headstocks so that all they need are a light finish touch up)

He said that there were probably better ways of attaching the back, but that he actually likes roping the back down, it's fun for him.

Same reason for profiling the back the way he does, although currently he omits the extra profiling of the tailblock as being unnecessary.

So sometimes the reasons for doing something a certain way are that

1)It's good enough (meaning there are no structural or aesthetic problems)

2)It's fun.

So it may not be necessary to bevel the edges to match the radius of the back, but it indeed may be more fun, and possibly more satisfying.

Me, I like the fact that I get good results without feeling like I MUST match the edges. (However, I must poit out that the edges DO match under clamping pressure.)

Tooling and skills have nothing to do with it.

If you think about it, it takes less skill to spin a radius dish around on the back of the instrument and call it done than it does to meticulously sand around the edges, blending various planes, angles, and domes by hand to produce a good and aesthetically pleasing result (IE glued tightly around the circumference with no gaps, and no unsightly dimples!).

I'm not trying to rankle anyone's feathers here, I'm not offended in any way, just my point of view.

I'm sure Cumpiano possesses the correct skills necessary to radius a back using dishes if he really wanted to.

So it's not fair to say that a deficient skill factor would be a reason for NOT using radius dishes.

However, they certainly look faster and more efficient than what Cumpiano is doing, which would be a very good reason to switch.

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Old growth, shmold growth!

I like to choose methods that are easier and more accurate. Different strokes, eh?

For different folks!

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Old growth, shmold growth!

I've been thinking about the training of beginners in my shop. It is not hard to get good results out of their efforts but a lot of this is due to the availablity of good tools and jigs. When they go back to their home workshop to build #2, the results may be disappointing due to the lack of tools and jigs. I am not sure how to handle that. There is something to be said for limiting the jig/tool usage to the basics to prevent this problem.

Now this isn't on topic with my original question. But I am building a guitar with slightly different dimensions than Cumpiano's. Slightly narrower lower bout (an inch narrower) and a half an inch shorter. Now I'm concerned that the bracing curvature is too much for my smaller guitar. Do I need to adjust these curves to match a known radius?

My other question is about the neck angle. It seems Cumpiano is getting the proper neck angle without adding an angle to the shoulder of his neck tenon and getting it through the head block. Is this going to change on my smaller guitar. Now I'm starting to question myself using the Cumpiano method as there are some variables that don't seem all that precise. Do I need to stop thinking and just get on with it? I do know that the neck angle is really the deciding factor on whether I build a playable instrument or not.

Hopefully posting this question here will get some replies, just didn't want to take up another thread with these questions.

b
You can use whatever radius you like to build. There are probably nearly as many radii used by the builders on this forum as there are builders themselves. But I think that the difference in size of the guitar you are contemplating is not large enough to worry about. The Cumpiano radii should work fine. I will be building an L-00 using the Cumpiano method(my first acoustic build as well), which is much smaller and a much different shape, and I'll be usung the same top radius, but changing the back to 20'. The method used in the book should work to build any type of acoustic guitar you want.
As to the neck angle, no matter what the book says, or anyone else says, I think it would be a mistake to think that the neck joint/angle will be spot on, no matter what the method used. Too much room for error no matter who is building. MHO. I fully expect it will be necessary for me to have to do a little flossing with sandpaper, or by other means adjust that neck angle to get the proper set back. That's gonna be part of the build for me, I think, no matter what method I use.

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Mike

The only thing nescessary for evil to thrive is for good men to do nothing.

So exactly how long do your tutorials take and how much do they cost?

Do you help them build neck jigs and binding jigs, radius dishes, go-bar decks and the like?

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Old growth, shmold growth!

Dubba post

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Old growth, shmold growth!

Are you talking steel string or classical?

Natelson did all the classical portion of the text, and Cumpiano did all the steel string text.

Cumpiano's neck block is square to the soundboard and shoulders, and the neck heel is square to the neck block. The actual neck angle is set by the UFB!
The UFB is curved so that as the soundboard is glued to the curve, the portion of the soundboard that the block is glued to tips back by a degree specified by the amount of UFB curvature, so that the neck block is squared to the shoulders and orthogonal to the soundboard, in effect tipping the actual shoulders back along with the neck block. This also makes the neck straight from the nut to the end of the fretboard while maintaining the correct neck angle and, string height above the soundboard at the bridge.

The 5 degree cut in the book is no longer used, as that was simply to facilitate any neck finessing. He did that instead of chiseling the cheeks back prior to flossing, as is done during a neck reset or fitting a dovetail joint, or fitting a neck to a radiused soundboard. With the neck heel square to the block, that isn't really necessary, although you can certainly still do it of you want.

If the heel is tapered, it is done so on the back of the heel, it still remains square to the neck block, and so wouldn't affect the neck angle.

So you can change the neck angle by changing the degree of curvature of the UFB, but as long as your scale length is the same, that should be unneccesary, as the dimension changes you specified have nothing to do with the length of the UFB.

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Old growth, shmold growth!

Seriously, I'm genuinely curious..

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Old growth, shmold growth!

Not anytime soon, hah!

No way I could be gone 4 months.

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Old growth, shmold growth!

I agree with that approach and this is what I have done with the three guys that I have mentored. Much better to teach a person to fish in depth than to hand them a bass.