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Oops, sorry, i thought I was texting my wife back. Please disregard the "ok".


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OK.

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Phil

http://www.oleninstruments.com

"Those who tilt at windmills are only considered insane by those who can't see the dragon."

Actually it looks like your UTB (or upper face brace if you prefer) has sunk or was too flat to begin with for this particular build geometry.

The 90 degrees at the block is to be expected no matter what as your BLOCK was milled at 90 degrees, but the dip below that has another explanation.

For my builds I actually use the same radius template that I use for the back braces, but I start the curve on either side of the fretboard right where the edge of the fretboard would be and end it right where the side is at the soundboard with the 1/16th (14 fret) or 3/32nd (12 fret) offset.

From your picture it appears that your brace may have been too flat along the majority of the length.

You might simply have to put a wedged shim under the fretboard, unless someone has a better analysis/solution.

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Old growth, shmold growth!

"Humidity? Geometry? Clamping pressure?"

WARNING!!! Beginner opinion to follow:

I would place my money on humidity issues. Do you control your humidity in your build area and maintain it around 45%? Have you been using your heat more due to the cold snap down there? The drier air could cause some movement like this on a closed box. If you have turned the heat up recently you may want to try to rehydrate the box - a damp sponge inside of a large trash bag with the box overnight or a bit longer should do it. (Keep the damp sponge from touching the wood though) Remove box, and immediately check the area with a straight edge again, and note changes if any.

Another beginner opinion:

Nice rosette.

Set the square on the neck again and measure the gap at the rosette. Is it 1/16th of an inch?

Then you might have a flat UTB. Drying out could do that.

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Old growth, shmold growth!

It's very close to 1/16", maybe 1/64" shy but not much more.

Suggestions? Was the UTB not tall (stiff) enough?

This box was closed up in 2012, and has been sitting in my house ever since. Figured it would be better to keep it in here, where it will live, where it will at least be at a fairly stable temp, and not subjected to the temp swings in the shop.

So what should I do from here?

Tanks again for all the suggestions, I know I am taking lots of time with this thread. But I am learning what is going on, and it is much appreciated help. Also thanks for the compliments on my rosette!

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Phil

http://www.oleninstruments.com

"Those who tilt at windmills are only considered insane by those who can't see the dragon."

OK, next question. I put a wet paper towel in an open sandwich bag, placed it inside the guitar, and then put that in a plastic garbage bag and let it sit for two days. I can't tell for sure if there was any change at all, but it certainly didn't help with the angle of the upper bout. I'm going to take a few more measurements now and see if I can find any more info (fret board thickness, actual angles, etc.)

I would like to make sure I understand what is going on here before I start shaving wood. Any more suggestions? If the body is indeed too dry, what is the best way to rehydrate it if the plastic bag trick didn't help?

Thanks again,

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Phil

http://www.oleninstruments.com

"Those who tilt at windmills are only considered insane by those who can't see the dragon."

I throw my 25 cents in about humidity since I have re-hydrated a number of them. If you have a guitar case you can put it in then, do it. Find a small plastic container with a snap on lid and drill a number of holes in it (the lid). Cut a sponge to fit and wet the sponge and put that in the case with the body and neck. It will take a lot more than a day or 2 bring the wood back up to proper humidity. I would say a week or so since you do not have any finish on it. You must have a hydrometer in the case so you know where your humidity level is. Don't open the case more than one or 2 times a day and keep it closed but make sure it is around 45%. You don't want to try to humidify it too fast since that will cause cracks! You cold buy something like a Planet Wave humidifier but a plastic container works just as well and is free.

I have repaired a few dried out guitars and a couple of them were so dried out the bindings had pulled away from the body. In those extreme cases it has taken up to 5 or 6 weeks to bring them back.

What you are showing looks to be a clear case of low humidity and with having the neck off allowed the sound hole to sink much easier since it only had the UTB to help hold it in place. How is the radius on the rest of the box? It it is shallower than what you put on it when you built it that would be a sure sign.

Given the information we now have, it seems that letting the box acclimate to the environment naturally and then following this sequence should yield an acceptable solution.

I would add that refretting and re-radiusing the fretboard once the neck is permanently attached would give extra assurance.

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Old growth, shmold growth!

If you need to flatten the fretboard area before that though I would start in the middle and focus on getting the area flat toward the neck joint, and if it dips down toward the soundhole a little that's not a HUGe concern. Get it as flat as possible, but don't scrape a hole through the top.

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Old growth, shmold growth!

This helped me get my head around the entire neck set geometry issue -- useful in prepping rim as well as corrective action.
http://www.kennethmichaelguitars.com/neckangle.html

Alright everyone, thanks a lot! I think I now have a good handle on what is going on. I remember when I first closed the box I did a quick check, and that area on the upper bout was not only straight, but gave a nice small clearance at the bridge location. I didn't measure and record the dimension, just gave it a quick look to see if it appeared right, which it did. This sinking has happened in the time since.

So, the project goes on hold again, until I can get a handle on humidity. I will get a hygrometer, and come up with a way to enclose everything, and wait it out. I won't sand or cut anything until that is done, and then the whole thing will be evaluated again at that time.

But this does lead to one more question. If this body flattens out when dry, then will it do the same thing to the same degree once it is finished? I am curious as to whether the action might get too low if it gets dry in the future.

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Phil

http://www.oleninstruments.com

"Those who tilt at windmills are only considered insane by those who can't see the dragon."

I was closing up some boxes today and remembered this thread. Thought I'd show a couple of things that have helped me with the upper bout/ fretboard/ neck set thing.

I radius my tops to 30' Just pulled the number out of the air 10 years ago and too lazy to change. This means I have to flatten and angle the upper bout a little to make the fretboard extension coplanar.

I stick a pivot point at the location of the front of the bridge and of a thickness that it will get me close to the angle I want. For my double tenon bolt on neck that is just a little less than bridge height as i want some drop off on the upper bout so that it will yield a straight fretboard extension under string tension. The sanding board has a 1/4" piece of plexiglass attached to mimic the fretboard.







This sands the angle into the rimset and flattens the radius in the upper bout.

After the top is on I fine tune and flatten the area under the fretboard with a Fox paddle. I have recently started putting a slight radius in the top brace instead of leaving it flat as I used to do. Todd mentioned this and I think it's a great idea. Any doming secondary to that is easily flattened by the paddle with a minimum of sanding.



This gives the relationship of the upper bout to the neck set that I want to allow the extension to be coplanar after string up and settling in.



The actual neck set will put the straightedge about 1/16" over the bridge which for my guitars gets me close.

The big trick is getting a handle on how much your guitars move on string up and settling in so you know how much drop off to put in the upper bout and still have a coplanar neck after string up and settling. That takes a while to get a handle on. I think as a general rule I've found that glued dovetails and extensions move the least, bolt-ons with a glued extension a little more, and double tenon bolt-ons have the potential to move the most and may require extra support or techniques to add stability. I had it down pretty well and then Todd got me putting a radius on the top brace (plus some other new stuff I'm doing) and now they are not moving as much! "Recalculating"

One thing you do NOT want is a rising fretboard extension under tension and if you are perfectly coplanar unstrung and not using a neck with a supported extension like Trevor you'll probably get a rise.

Again a million ways to get to a satisfactory end point with all this. This is just an approach that has worked for me.

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It's not what you don't know that hurts you, it's what you do know that's wrong.

OK, time for some advice. I put the body of the guitar in a plastic garbage bag with a wet paper towel inside (in an open sandwich bag, so no direct contact) and let it sit for two weeks. My new hygrometers came in from SM this weekend. Last night I put the guitar body and the neck into a big plastic bin, the type you put clothes in to hide under the bed. It has a lid that snaps closed on the ends. I put the small digital hygrometer inside, and I also put my wet paper towel in the sandwich bag in there.

This afternoon, the hygrometer in the plastic container reads 52%. I do know that the body is coming back into shape, there is still a bit of sag in the upper bout but much less than before. The neck has been sitting out in the house, humidity around 32%, so it has only been in the humidity box overnight.

My question is, how long do you think I should let everything soak in that container before I check the neck fit again? Any good way to tell? After the trouble I've had, I feel like I would be amiss if I put a dry neck on a not so dry body. On the other hand, I really don't want to wait another month or two unless I have to.

Any ideas? Thanks again for all the help and suggestions!

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Phil

http://www.oleninstruments.com

"Those who tilt at windmills are only considered insane by those who can't see the dragon."

Yeah, it looks like that top is dished inward. That will surely cause the gap you're getting.

For me, and I think it's pretty common on Martin-esque guitars, it's pretty simple.

1) The top is domed. I use 28' radius. Some people go 40'. This domed top is glued onto flat rims...ie the rim is not sanded on a sperical dish, but the kerfed lining is beveled back at 1.5 degrees or so. The domed top will give you a 1.5 degree ramp from the neck block towards the sound hole.
2) You cut the tenon on the neck such that the shoulders are angled away from the vertical by the same 1.5 degrees. ie.. the angle between the cheeks of the neck heel and the fingerboard place is 88.5 degrees. Teh angle between the face of the neck block and the top is 91.5 degrees.


If you get somewhere close to these numbers, the upper bout area on the top should match up well with the fingerboard extension, requiring verry little to glue/clamp it down.


To me, it looks like your top is dished inward, not outward, thus creating the gap,.

And FWIW, I'm not sure how people build with a 90 degree angle at the neck block, you HAVE to have an upshot fingerboard to get to 1/2" string height at the bridge.

Hello everyone, I'm back! (yea me.) Don't know if many of you remember this thread, but it was at this point that the frustration finally caught up with me, and I had to put it down. As it turns out, I put it down for 2 years. Yikes. But, I have been thinking about it, and today I finally got back to work. I managed to recut the neck angle, sand the top, and get what seems to be very close to where I need to be. I think I am close enough now that I can make this work, and finally get my first guitar finished.

My question is, how close to perfect is the fit of the neck heel on the body? I am close, but how close is close enough? By using a piece of paper as a shim (approx. .004" thick) I am within .004" on one side, around .010" gap at places on the other. I would think that small of a gap could be filled with finish, but I plan to finish the neck and body separately.

so, here are a couple of before and after pictures showing today's progress. I can keep flossing if necessary, but it seems at this point, that may be more cosmetic, and my No. 1 may not be absolutely perfect. Any comments welcome, especially about how close I need to be to call it done.

Thanks again for all the help, I haven't given up on this yet!

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Phil

http://www.oleninstruments.com

"Those who tilt at windmills are only considered insane by those who can't see the dragon."

Hi Phil, I think I'm a little late to the party, about two years.

I take it that is a bolt on neck? To get an accurate picture of where you are I would leave the bolts a little loose, put a clamp on the fingerboard clamping at the 14th fret clamping it fairly firm to the body. Then tighten the bolts slowly. Doing the top one first.

That may change the way the neck to body and FB extension joints look.

Then lay your straight edge on the fingerboard and check the neck angle and don't forget the centerline of the fingerboard.

You will want the neck to body joint much closer than it looks in the picture. But...

As you bring the joint flush you must maintain the correct neck angle and center line alignment.

I battled with this on my first couple of builds also until I discovered that the time to get things right was before the lining and top went on and before I made the neck. It is actually pretty simple. After the neck and end block are attached to the sides I get the top edge of the sides good and flat. Then I mark about 2 inches in front of the waist on both sides and make a mark about 1/10" down on the sides at the neck joint. Then I plane and sand a taper into the sides starting at the 2" mark to the 1/10" mark. This gives me a ramp down to the neck. I clamp the unbraced top down and lay a straight edge on the fingerboard extension area. I adjust the ramp until I have the right space that once a fretted board is installed I will have enough room for a bridge + 1/32". I put the linning in and check again. Once I like it I glue the top on.

Then i use one of those adjustable squares to get the angle between the top and the neck joint area and I cut that angle into the neck.

If I do it right very little adjustment is needed as I assemble.

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Joe Beaver
Maker of Sawdust

Welcome back. This may be helpful to you: http://www.luthiersforum.com/forum/viewtopic.php?f=10102&t=15022&p=214039&view=show#p214039

The middle picture makes it look like the sides have a slight bow. If this is the case, flattening them at neck area might help close up the gaps on the sides. If the neck and fingerboard is in the proper relation to give the proper height of the strings above the soundboard at the bridge, and you still have the small gap under the fret board at the 12th fret, you could scrape away some of the rosewood under the center of the fret board extension and then floss the edges (much as is done for neck resets) to create a slight taper on the fret board and make a tighter fit. Alternatively you could fill the gap with a shim or rosewood dust and lacquer mixed together to make a wood putty.
One of the most important things to do with the first, is to finish it, even if it is slightly imperfect. Then you can take what you have learned and make the next one better.

I checked out Hesh's tutorial. It is excellent !!!

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Joe Beaver
Maker of Sawdust

Hey, thanks everyone. I appreciate the help, and you have shown me some wonderful, useful techniques to try. When I took these pictures, the angle of the neck was close to where it needed to be for height above the soundboard, or at least I think so. Then I found the center line was way off. So I made an adjustment, went too far, and it now the joint looks much worse than the photos. Oh well, I'll keep sanding and flossing, and see how it goes. So many things went wrong with this first one, in spite of my best efforts. Just too much to understand all at once, I suppose. The learning curve on this is steep and long, at least for me. And I am also seeing the problem of making my first one out of ash, so I am now flossing ash end grain to set my first neck. Oh well.

Still, it's good to be back!

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Phil

http://www.oleninstruments.com

"Those who tilt at windmills are only considered insane by those who can't see the dragon."

I always thought that the measure of a builder, at least for the first few, was how well you overcome the problems encountered alone the way. We have all been through what you are experiencing.

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Joe Beaver
Maker of Sawdust

Joe, thanks for the encouragement. I have overcome many obstacles on this project. Had a list at one time. Started making two at once, which resulted in 5 tops, 4 rosettes, multiple backs, both guitars bound then cut away and rebound, the list goes on and on. I finally stopped the second one, concentrating on getting one done. So far, I am satisfied that at least appearance wise, everything on this one is as close to perfect as I can get it. Well, until now.

I did work on the joint today, and it is very close to where it needs to be both in angle and alignment. unfortunately, it now looks worse than ever. I have a gap on one corner big enough to stick a thumbnail in. It may be functional at this point, but it looks terrible. I will get the appearance better. Just have to keep going.

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Phil

http://www.oleninstruments.com

"Those who tilt at windmills are only considered insane by those who can't see the dragon."

The three-dimensional jigsaw puzzle of correct neck set, yaw and a gapless joint is one of the most finnicky stages, especially for your first couple guitars. Hang in there - it gets easier with experience and as you continue building you'll probably find a variety of ways to tweak your earlier processes to make things as easy as possible for yourself when you get to this stage.

You had a question about why not having the guitar end up with a saddle much higher than normal. The answer is that you are messing with a factor that has a major influence on the tone of the guitar. High saddles tend to make loud but unpleasant sounding guitars.
I liked all the advice about how to reshape the trouble area on your neck joint. You might also find it useful to make precise, thin, angled shims to eliminate the air gaps. In reshaping an area it is sometimes helpful to add a little wood as well as remove it.