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duplicate

I have not worked with dovetail necks, but my first thought is, find out why the fretboard won't seat at the body joint. If the neck fit before, a clamp should pull it down. Look for a bit of glue squeezeout maybe, in the neck joint, or at the end of the fretboard where it is glued to the neck. If you can't get it seated you may have to adjust the neck joint (removing the fretboard might be necessary), and make sure the neck joint is perfect. When you do get it seated, make sure the fretboard is straight. It may have curved down because of the fret installation, and will line up straight with clamping. If the extension rises over the guitar body, then you need to either sand the upper bout to fit, fashion a matching tapered shim as MaineGeezer suggests to fill the gap, or take some off the underside of the extension, tapered from the soundhole end to nothing at the neck join. I've had to do this a couple of times and it's fiddly but if you start by removing much less than you think you need, and then do more as necessary, it can solve that part of the problem.

viewtopic.php?f=59&t=9832

You can also remove frets and taper the top of the fretboard as Peter suggests. Whatever you do, you may raise or lower the saddle height too, so figure that out before you decide which route to take. Bruce W.

John
I would do this. The frets could be causing the distortion on the extension. Forcing it down and expecting the glue to hold it flat can work and shouldn't affect the actual joint once you get that fit right.
I'd pull the frets off the board on the extension and see how much it flattens out. I'll bet it does at least some. Then get your joint right so the neck sets all the way down. Make sure the top is flat from the edge to the sound hole...flat sand if necessary as much as you safely can to get it flat. Then set the neck in place and check that extension fit. If it's better consider installing the neck gluing it in and glue down the fretboard clamping it flat. After dry reinstall those frets and relevel them.
I think it will turn out fine. Fretboard are quite flexible but stiffer with the frets installed. Does this make sense??

Thanks so much for all the input!

Yes, the fret board was straight, and, as expected, after fretting it was curved downward. I did have the neck joint set up pretty well, too, I thought. I did have to use a shim. I did clear out the squeeze out from gluing the fingerboard on. I also sanded off the finish on the upper bout at the joint and any that “spilled over” into the dovetail. I also checked that the top of the guitar, under the fingerboard extension is still flat.

An important thing I left out in my post was that before I tried putting on the neck, I found the bottom of the fingerboard extension was not flat. So, I did some sanding to flatten it. I had done this on the guitar I just finished last week, and had no issues. On this guitar I had to take off more to get it flat.

So, based on that and the input I got, here’s what I’m thinking: The sanding I did is what created the gap I’m seeing. (I sanded more than I thought I did.) Kevin Sjostrand said something I wanted to know – that the fingerboard should be flexible. I’m clamping pretty hard, so I didn’t know if the fingerboard was preventing a tight fit, or the dovetail joint. Now, I think it’s the dovetail joint. So, by sanding, I created a gap and now have to send to lower the neck.

Fingers crossed, I’m going try carefully sanding the face of the tenon to lower the neck.

“Tickle and test”!

Ok, I think I’m good.

To verify what I was thinking, I took the piece of fingerboard that was cut off and placed it against the fingerboard extension. The cut off piece was thicker by, maybe, a 32nd, indicating that I had sanded off that amount when flattening the bottom. That gave me a bit more confidence that I should lower the neck.

I sanded the tenon face a little at a time and measured the gap shown in the above pictures and it lowered nicely. After five or so go’s at this, the fingerboard extension is now flush with the top and the neck, I think, still seats well, and the neck angle is still ok.

Gluing next.

Thanks again for all the input. It really helped me sort through this.

(“Tickle and test”! - I like that.)

Just finished the other of the two guitars I’ve been working on.

It seemed to come out well. I am worried about the neck joint. The fit wasn’t as tight as I thought it would be when fitting it earlier. The shoulder is just not perfectly flush against the body. It’s on, so I don’t know what to do about that.

While I was relaxing installing the tuners, I had a little accident. I put the 6 bushings and 12 tiny little screws in a plastic cup while I was working on the installation. I thought to myself – boy, if I lost one of these parts it would be a pain to replace it. Right in the middle of that thought, I knocked over the plastic cup. Spent the next ½ hour on the floor with a flashlight searching. Thankfully I found them all.

These two guitars will go to family members. It’s been fun and useful to build two at once. I think I’ll keep doing that if I can.

Now I have to think about what to do next….

Thanks so much for the great help and input from the forum!!

They look great. Always a good feeling to be done and pass them on to the new owners

I can relate totally to the "drop". Only usually I don't find them all.

Now on to the next one. What will it be?