This is the 12 string slot head successor to the FG-230.
After talking by email for the past week or so we met at his hotel in Mystic CT. He was on vacation from Boston for a couple of days. While the ride up was fine, we hit a little more Labor Day traffic on the way back.
When I got home I did my usual inspection. Measurements, external pics, remove the strings, more measurements, internal pics. Then I start the disassembly.
It's in pretty good shape, cleaner than most. Except the action is 3/8"!!! The worst I've ever seen! And the bridge is tipped up, just as the neck is pushing into the body. Typical of these old Yamaha's.
While the string action is a mile high, the nut action is perfect. And the edges of the frets have huge ramps, so there's no reason to replace the nut.
Zero break angle for the rear strings because of the bridge tipping.
Then my string of luck came to an end. At 6 minutes (my max steaming time) the neck wouldn't release. I unclamped the neck from the table and undercut the heel deeper with the scalpel. And steamed for another 3 minutes. Still won't release. No movement on the right (bass) side. That's typical if the face of the heel is glued to the face of the guitar. So I undercut it deeper. Of course, the undercut can't be straight in, so if it's glued on the full length of the heel the pressure from neck jig has to shear all of it off to release. The undercutting is just to be sure the tearing doesn't go into the visible part of the guitar. After SIX steaming sessions there's some movement on the right side, but there's a crack in the finish at the heel/neck glue joint and it still won't release! So I put it down' took the jig off, and used the hair dryer to try to dry some of the joint out. Maybe try again tomorrow. THIS IS A FIRST!! I've always been able to get the neck of in 10 minutes or less, even if the face of the heel was glued to the side of the guitar. The jig pressure was always enough to cause the material to shear. Not this time!!! Need to think about it...
I GOT THE NECK OFF!! And it's the worst case of "TOO MUCH GLUE" I've ever seen!!!
You can see glue on the whole heel face that was stuck to the guitar body. And some mahogany from the neck pocket stuck to the dovetail.
THIS is the side that gave me the most grief!!! There is a HUGE amount of mahogany from the side of the guitar stuck to the heel face. And a chunk of the dovetail was pulled out (already glued). AND the dovetail shim (light wood) actually TORE instead of loosening from the dovetail. There's also a crack at the heel/neck glue joint, AND a scratch I made with my scalpel right before I gave up last night. I can fix them.
You can see all the glue on the face of the guitar where it was stuck to the whole face of the heel!!! And the dovetail shim that had to tear.
This is by far the worst neck removal I've ever done! SO MUCH GLUE ! ! ! !
Now I will let it dry out for 2 or 3 days before working on refitting it, before starting the neck reset.
And 3D model the bridge, and make & install the Bridge Doctor to straighten the bridge.
Last night I starting making the bridge doctor blocks.
The threads for the adjustment are formed not cut. I had the tip of a set screw turned down to .280" diameter that is threaded into a 9/32" hole drilled into the blocks, in and out, a little bit at a time until I get it in to the 3/4" full depth. Then I go in and out a few more times. At that point the set screw is very hot from friction so I put it in the freezer for a couple minutes to cool it off. Then thread the next one. Then I flood the threads with water thin super glue to harden the threads. And get the stuff all over my hands and hopefully not stick to the block. It is very messy! Acetone and Goof Off takes it off my hands quickly. After they sit and harden for a couple of hours I dip the set screw in some light oil and run it in and out a little at a time, like before, to open the threads again.
Tonight I'll do it again with the set screw that's actually staying with the block. And thread in and out the #6 x 2" sheet metal screw that attaches the block to the guitar.
Once the blocks are done I'll sand them and wipe some kind of finish on them.
Well, bad news. The threads in maple failed, even hardened with thing super glue. I was picking at them with a toothpick and pulled them out. I tried that with one of the oak blocks I made previously and the threads seem solid. BACK TO OAK!!!
Tonight I removed wood stuck to the wrong places, sanded the heel surfaces (inside and out), and refit the neck to the neck pocket. I also undercut heel (in preparation of starting the neck reset), and backbowed the neck to adjust the the truss rod to get the neck flat.
The neck now projects 1/8" below the top of the bridge, and is centered to the bridge. Since the amount to be sanded off of the heel for the neck reset is 1/3rd of the change required at the saddle, .12" (neck projects below the bridge)+ .08" (want the neck to project above the bridge)/3 = Change at Heel, .20"/3 = .067" off of the heel. In theory! NEVER sand right to the number. Sneak up on it and check your progress often. I marked the heel at .05" and will check it a few times during sanding.
I also fixed the side of the guitar that was lost when it wouldn't release from the neck. I use the same .022" thick maple veneer I use for neck pocket shims. Carefully cut to fit the curvature, then attached with superglue, the carefully trimmed and sanded to fit the dovetail, and the top sanded to fit flush with the side of the guitar.
Now the neck reset can begin!!! Tomorrow!!!!
Cleared the pocket.
Fit the patch.
Trimmed the patch.
Sanded the patch. Later a furniture marker will make the maple look very close to the mahogany color.
I forgot to add WHY I did that patch. While that surface is under the heel won't be visible, I need a flat surface to do the pull sanding to taper the heel.
Tonight I undercut the heel in preparation for heel sanding, so I don't have to sand the whole surface. I do it with a Dremel and a 1/8" ball burr bit.
Then I did some pull sanding of the heel. I put masking tape on the side of the guitar just outside the heel area. I use emory paper with a fiberglass tape backing (less friction). I wear a work glove with extra padding on the knuckles.
Then I pinned the heel crack, just in case. I drill a 9/64" hole to start, then open it up to 13/64, 1/64" clearance for a piece of 3/16" oak dowel. Epoxy is dripped into the hole, the dowel pushed in, and the area cleaned.
Dowel set in hole. Tape protecting surfaces.
Cleaned up. I'll cut this down tomorrow with the Dremel and the 1/8" burr bit.
15th fret re-installed. This is a multi-step process. The fret slot needs to be opened with feeler gages to .020", the drilled holes need to be plugged (without filling the slot!), the slot opened to .020" again, the slot opening edges chamfered to make installing the fret easier, the old 15th fret straightened, and the old fret hammered/crushed back into place. This probably took an hour or so.