I did a little more sanding on the heel last night. And installed the tuners, clamped the guitar in the neck jig, and installed the old strings. The action is a lot higher than I expected, and the neck is slightly off center, so I put it down for the night. I'll take a closer look at it tonight. Sanding the heel is working in 3D, wanting a change only the neck angle, but sanding more off of one side (or unevenly) results in rotation, throwing other things off. That needs to be corrected first while there's still wood to sand, then get back to the neck angle. There are more variables than you think when working in 3D. And I'm sanding by hand to a few thousandths of an inch. I've learned when something doesn't seem right, walk away and come back to it another day. This is no place to screw up, it can't be replaced.
I had a couple of nights of fighting with the action and neck centering. Since I got the guitar the action has been a 1/32" difference between the E strings, normally a 1/64" difference. I've only seen this once before. I've always figured since I'm sanding a wedge off of the heel I could just sand more off one side of the heel and causing that side to tip back further, decreasing the action on that side only. It sounded good in theory. Until I tried it. All it did was cause the heel to rock on the side of the guitar. The neck is pivoting where the fretboard meets the top edge of the guitar. You CAN'T change the neck angle independently because of that. It will only pivot in one plane. Any uneven heel sanding will cause the neck to rock, and turn off center.
But I was still wondering WHY the action was 1/64" higher than it should be on the treble side. As I'm driving into work I'm thinking, is it possible the neck is slightly twisted?? I took some pictures looking down the length of the neck. The nut makes it look worse than it is because the top of it is lower on the treble side than the bass side. But, it does look slightly twisted. Then, I put a straight edge across the body in front of the bridge. You can see there are dips in the top where the wings of the bridge are. The 2 lines on the top are the location of the E strings. The dip on the bass side carries into the low E area, maybe 1/64". That could be part of the problem.
You can sort of see a twist by looking across the fretboard. you can see straight across the lower frets, but the top of the fretboard is slightly showing in the higher frets.
The dip in the low E area of the top.
But whatever the cause, I need to correct the action by sanding the bass side of the saddle lower, which will make it slightly lower than the treble side. It doesn't seem right, but 50+ years old guitars can do strange things with all that tension on them for so long.
So my experiment failed and I learned something valuable. I straightened the sanding on the heel, and tool a little more off to get the action where he wanted it. And sanded .03" off of the bass side of the saddle.
Today is the big day!!! I removed as much of the finish blushing I could. This is caused by the neck removal steam getting into the lacquer. I've always figured, heat put it there, heat will take it away. I use a hair dryer to heat the areas. A few times. Most of the blushing is gone. Then I polish and buff the areas.
Then I touch up any exposed wood areas with a maple finish marker, check the neck fit again, practice my clamping (very important!),and glue the neck on with hide glue. Hide glue must be applied HOT (heated to 145° F), and the areas need to be warm so the glue doesn't gel before the clamps are set. So I heat the neck and top with the hair dryer. The glue is applied with an acid brush, the clamps installed, and we wait 24 hours for the glue to dry before putting the strings on.
The neck is strung at full tension. The neck relief did increase slightly at full tension so I snugged up the truss rod to bring it down to normal. The low E action is 3/32", as expected. Somehow the high E action is down from 5/64" to 1/16"?? That's odd.
One thing that bothers me is the heel crack is open .010" on the bass side, a little less on the treble side. It was closed while I was working on it, of course with no string tension. There are 2 hardwood dowels in there, on an angle to get into the middle of the curve of the heel. I kind of wish it was broken so I could have glued it properly. I can see light thru for the first 1/4", then nothing. I could remove the string tension, and heat some epoxy to thin it and wipe some into the crack, but I have no idea what's in there, dirt, smoke, glue. If the crack is dirty nothing will stick.
And it sounds great!! Even with the old strings.
The normal plan is for it to hang for at least 2 weeks to let the neck settle in, 4 weeks is better, just in case. The virus is supposed to peak in our area mid-May, they think.
Tonight I rounded over the back of the nut & smoothed the outer edges. And sanded a little off the bottom. The nut action is close, about .010" high. I'll leave that for the final setup. Still need to finish fine sand it. And finish the fret ends.
I asked him if it would be OK to wipe warm epoxy (to thin it) into the heel crack, and he agreed. I loosened the strings, clamped the guitar in my neck jig, and attempted to use some clamps to pull the neck down to close the crack with no success. So I wrapped the neck in masking tape, heated the heel and epoxy with the hair dryer, and wiped warm epoxy, many times, into the crack. I let it set for a couple of minutes and wiped up the excess with alcohol, removed the tape, ant wiped the heel with alcohol. The finish is a little hazed but that will buff out.
It will either help or do nothing. I have no idea how clean the crack is or how long it's been there. It could be full or smoke or dirt, or possibly may have glue in it. When I got it the crack was pretty much closed. It's possible when clamping the guitar in the neck jig the forces opened the crack slightly. I epoxied in (2) hardwood dowel in the heel while the neck was off.
Crack didn't close.
Taped heel & neck.
You can see the shimmer of the epoxy in the crack.
IT'S DONE!!! It's been about 3.5 weeks since the neck was glued back on. The action hasn't changed. So, today I finished the nut action, sanded a bit off the bottom of the saddle and added (2) .020" maple shims under the saddle for future adjustment. But first he wanted medium strings, so I opened the nut slots before finishing the nut action.
I'll check and retune it tomorrow, and pack it on Sunday, and bring it to FEDEX Monday after work.
This and the 1971 FG-110 I'm working on have gotten me interested in finding a wood to match the orangey stripy wood they used on some models. One of the Indian rosewood bridge blanks I got from LMII was very close to this. I sent them a message and they don't have anymore, it's pretty rare. The other option is cocobolo. I have some coming from Stew Mac and will buy a few from a couple of other suppliers for comparison.
Unfortunately, when I unpacked it originally I opened the bottom. So to repack it I had to dump the whole contents of the packing on the floor. And all the packing peanuts. I think I'll be finding those for a while. But, it is packed I think the same way it was originally done, all the packing is in there, including the peanuts. I'll let him properly dispose of them. I asked him "PLEASE don't send them back!!" ;?P
I love the grain in the bridge wood, I like it much better natural than if you had stained it dark. Looks great on!
Bridges I've made were from Indian rosewood. This is supposed to be rosewood, but this color is very rare these days. I'm trying to find bridge blanks close to this color and grain to make bridges from. MUCH less boring!!