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Air conditioning will also lower relative humidity, which can be a good thing while you are building, but a not so good thing if you built at high humidity and keep it in air conditioning (low R.H.) after it is built.

Don't know what your thinking is, but it is best to glue the top and back to the sides while they are in the mold. The instrument will go through an "adjustment period" from the time it's out of the mold till it is "played in". It's all part of break-in. Your ribs don't look too far out to get back into the mold without problems. There is no such thing as a stress free instrument.

. . . or at least keep it in the mold during the process of fitting the back (and the back braces) to the sides. If you notch the kerfed linings, but not the sides, to fit the back braces, then taking the body out of the mold for gluing on the back usually works out OK. The brace ends click into the notches. Or, if the sides would be unruly under those circumstances, make sure that you use something other than normal spreaders on the inside to push the sides against the mold. Some spreaders will not come out through the soundhole after the back is glued on. This is the equivalent of building a boat in your basement and not being able to get it out. A few dowels cut to the right length will usually work just fine for that part of the process, and dowels will either easily slip out or be amenable to breaking in half and then pulling them out.

Do you mean when I level the kerfing to match the sides to make sure I get the end blocks too? As far as taper, I followed the Kinkaid book where he says to taper the end blocks facing the top to 92 degrees. Not sure if we're on the same page here.

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Julie Moriarty
http://JulimorCreations.com

I notched the kerfing so that the top fits snug in place and doesn't move once seated. While trying to figure out a way to hold the top on while I flip it over, I kind of tripped across this idea


At first I just used the holes that were already in the form. I liked the idea so much I drilled some new holes and installed 16 clamps total. I can't see any gaps as I check around the edge but I'm thinking I'll still need to add a few more clamps when I am doing the glue up.

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Julie Moriarty
http://JulimorCreations.com

I am not authorized to speak for Haans, but what he is describing is a common thing. The end block normally is about 1/2" thick. But the kerfed lining tends to only stick out from the sides by about half that much. I'm talking about the gluing surface to which the top (or back) will be glued. It is a good idea to block plane the inside corners of the ends of the end block so that, instead of the gluing surface of the end block to which the top is glued being 1/2", it matches the kerfed lining and creates a fairly consistent rim of gluing surface to which the top (or back) will be glued.

This can also be an aid to top vibration (maybe), but Haans was focused on the fact that, as a guitar ages, the shapes of the braces and blocks can telegraph through the thin plates and make the top (or back) look lumpy and odd. If you block plane down the end block in the way described, that at least stops the end block from contributing to the lumpy look.

Here's a photo...



As Don rightly said, to leave the full block glued to the top and back opens the door for top/back telegraphing the block. Looks really ugly! Tapering it back to the kerfing, eliminates the problem.

Thanks for the pic Haans. I get it now. Unfortunately, I already glued up the top, and that includes gluing the full 3/4" thickness of the tail block to the top. Maybe I can chisel a bevel out of it. Could be a delicate operation...

Should the head block on the back also be beveled to the kerfing?

I glued up the pieces for the neck today. I'm going to make the neck before gluing up the back so I can make sure everything lines up. I also tapered the back sides and trimmed the braces on the back.

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Julie Moriarty
http://JulimorCreations.com

I really don't know if I would recommend chiseling. Depends on your skill and I would be wary of the top center seam joint, especially if you used HHG. Might work with a rubbery glue like Titebond. I'm very tempted to say leave it for this one. Won't be your first mistake and I did it the first time too, way back when. You may notice that I used 7/16" Baltic birch plywood for the tail block.
As long as your neck block is perfectly sanded to the arch you put in the back and ribs, you are fine with the block running all the way down to the back. Most all hardwood backs will not telegraph like the tops.

I did Titebond the top. But I've been thinking of just putting this in the learn column and let it go.

I've been following the Cumpiano book to taper the sides for the back. Seems to include a lot of feel for how and where to taper it.

Does this profile look right?

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Julie Moriarty
http://JulimorCreations.com

I don't know much about Martins, but looks OK to me if you sanded with the same dish you braced it with.
Does the back distort any when you clamp at the neck block?

Julie--

Can I assume that you followed the Cumpiano/Natelson book in the sense that you used a flat piece of plywood with sandpaper stuck to it, and just sort of "eyeballed" the curve to put into the back? If so, then yes, it looks good. I think the important thing there is to make sure you have sanded the head block such that, when you glue the back to the sides, the head block is sort of flush with the sides, so the head block will glue to the back without a lot of clamping pressure being needed to make it all fit together.

Do you have something elastic to use for closing the box (like recommended in the Cumpiano/Natelson book), or are you going to use those clamps I see in the photos? If you use the clamps, you might want to cut a clamping caul out of hardboard or pegboard. Just cut it to the shape of the guitar, then cut out the middle, so you have a 3/4" wide strip that follows the outline of the guitar, inside the line. That can do an OK job of spreading the clamping pressure out.

Haans, I don't see any distortion as it is. But I made a boo-boo with the head block I'm going to have to remedy. I cut the headblock square at the bottom. So I'll have to add a wedge if I'm to glue the back to the entire surface of the block.

Don, yes, I sanded with a flat piece of MDF and eyeballed as I went along. Then I compared measurements side to side and made any adjustments to get both sides on the same plane. As for gluing the back, I'll probably do what I did on the top and use cauls and flat stock under the clamps.

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Julie Moriarty
http://JulimorCreations.com

Yup, a wedge will do it.
It is always best to sand the ribs and blocks to the same shape as your dish. That way, everything fits well. No reason you can't just sandpaper the dish with 60 or 80 grit and still brace your top or back on that. If you are uncomfortable with that, slip a sheet of paper over the dish before bracing. Here is a cylindrically braced top with the X braces just glued on over 60 grit...

I have the MDF dishes for both plates and I used them to shape the braces. But when it came to using the dishes to sand-shape the sides, I became concerned about the effect it will have on the angle of the neck. Thus I didn't use the dish for the top.

When it came to the back, the different heights at the blocks seemed to negate the dish as being useful in sand-shaping the sides. Maybe I'm not seeing this right but it's been my understanding from reading Guitarmaking by Cumpiano that the back remained parallel to the top from the end block to about 2" before the waist and then begin the "drop off" down to the top block. Forming a curve in that drop off area.

Am I not seeing the geometry correctly?

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Julie Moriarty
http://JulimorCreations.com

Julie--

The Cumpiano/Natelson book guides the reader in building an acoustic guitar without dished workboards. Other sources recommend dished workboards.

Here is how to visualize how they are not all that different in the end:

After gluing the sides to the top, such that the top is mostly perpendicular to the sides (I know that is not what we want at the neck joint, but assume with me for now), imagine if you were to taper the sides before gluing on the back, such that the width of the sides at the head block is 3/4" to 1" less than the width of the sides at the tail block, but that plane for the back is perfectly flat. Then imagine if you were to use a 15' radius sanding dish and sand that radius into the sides. The plane is no longer flat; it is has been made spherical. And it is still tilted toward the head block, because of the taper. That is going to look a whole lot like what you wind up with if you use the Cumpiano/Natelson method. Not precisely, but a lot like it. So, they aren't all that different in terms of the finished product. They are just very different ways of getting there.

One of the struggles I see going on for you is that you are sort of following one method of building, but then sort of following another. I think you can do that after you build a few guitars, but it makes it harder to get your first one to come out right. Some methods don't mix and match well.

Yes, but you are referencing a book published in 1989. A lot of water under the bridge since then.
I always would rough cut the ribs before bending, that gave the general taper, then sanded with the dishes, well, the top was sanded front to rear and back. It guarantees you a perfect fit between the ribs/kerfing, blocks and top or back. My radius' were 10'. Never worried about neck angle because the top was flat in that dimension. One half degree usually did it for me.





They also made a great way to glue the top and back on. Ultimately, you make the decisions, we just try to help. Lots going on upstairs on your first acoustic!

If you already have the dished work boards and molds, using them for every aspect of the build until the box is closed is definitely the
way to go, as Haans suggests. My sides live in the mold until top and back is attached. Bracing and shaping is done on the dishes or with them
on top. That's the real purpose of using the dishes and molds, imo. Lottsa vids. and such on youtube of people using this approach.
Sure. there are other methods....but.

You're right about that. And besides the two books I have, I'm also grabbing woodworking and electric guitar building experiences and also throwing that into the mix. When I built my first electric guitar I adhered religiously to one plan but it was a very detailed and comprehensive plan. I got the Kinkead plan with his book I bought several years ago. But the plan left too many questions. So I bought the Antes plan and that, too, had a lot of holes.

I didn't draw up my own plans for this build like I've done in the past. The time taken to draw up the plan, combined with all the research needed to make a complete plan, gave me a big head start when I finally started building. Today I find neither the Antes or Kinkead plans can be relied upon for making the neck so it was back to the books and then finally to CAD. I may just do a complete CAD drawing for the OM before this is all done.

_________________
Julie Moriarty
http://JulimorCreations.com

I'll give that a shot on the back and see how it goes. I'm not really crazy about the stresses put on the back plate with the way it is now.

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Julie Moriarty
http://JulimorCreations.com

You can use a dish to level the backside of the rim even if you intend to have the taper increase between the waist and the heel block. When I do that, I sand the rim in the dish like normal to get the lower bout all set then tip it all forward to sand the upper bout taper down to the waist. You can do a little fairing in on the dish right where the taper changes. Then when you put the back on you just bend it down over the rim to the heel block. It doesn’t take nearly the amount of force you are imagining.

This is the best picture I could find. You can see the guitar in the foreground tapers more at the waist and the one in the background is a constant taper. Both done in a radius dish.



Sent from my iPhone using Tapatalk

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

Julie—

Please don’t misunderstand my comments about mixing and matching techniques. I think moving beyond the Cumpiano/Natelson book’s methods to things that work better is a good idea. I currently use dished workboards, and do a number of other things pretty differently from what I did when I built my first guitar using the Cumpiano/Natelson book. But if I had varied too far from the book my first time out, I would have run a greater risk of getting stuck with incompatible techniques. I think it takes a bit of experience to be good at figuring out what you can change without causing a problem.

In your situation, if you started out using dished workboards, I am with Haans in that those dishes can, and should, be used to profile the sides to accept the top and back. That’s going pretty far afield from the Cumpiano/Natelson book, so moving back to the book for some related tasks can put you in a bit of a bind.

I’m confident you will get this all worked out, and I’m even more confident that you will learn a lot during #1 that will help you build #2 better, and so on.

Don, I don't think I can help taking all the information I've gathered from doing and reading and coming up with whatever solution I do. I've always been drawn to creating things but at the same time, when I'm really green, I pay close attention to the seasoned veterans. The easiest part of this build for me will be the neck because I've made enough to be comfortable with the work. The hardest part so far was learning how to work with sipo. I was a bit on edge then but looking back it wasn't so bad.

I've got the neck rough shaped and I'm having fun using what's lying around in the shop to come up with something different in the choice of headstock woods. And I now find myself at that point where I've settled into the build comfortably. I didn't expect to get here so quickly but I think I did because of all the great help here.

_________________
Julie Moriarty
http://JulimorCreations.com

I've been putzing around with the neck lately. I decided to use the barrel nuts cited on Cumpiano's website to mount the neck. It will give me some flexibility. Anyway, here's where I am today

I initially began cutting the tenon with hand tools because it was late. I ended up squaring it on the router table.


I got the truss rod from SM. Not sure if the location or depth is correct though.

I think it was in Guitarmaking that I read the bottom of the truss rod should be about 1/8" from the bottom of the neck. Haven't checked that yet.

The fretboard will be cocobolo. I've had this piece sitting around for years


The radius will be 16". From what I've read, Martin used 1-3/4" at the first fret but now also uses 1-11/16". I'll probably go with 1-3/4".

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Julie Moriarty
http://JulimorCreations.com