Harmony H1457 archtop guitar repair

This is a Harmony H1457 Monterey archtop guitar. It's similar to the H1456 model but in a natural finish. It's got a replacement bridge and tuners but otherwise appears original. I'm not sure the age but I'd guess 60's due to the adjustable trussrod. It is naturally missing the pickguard and trussrod cover. Like all USA-made Harmony's it has a solid top, spruce in this case, which is coming apart at the seams.

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The gap at the heel makes this an obvious candidate for a neck reset. The action is really bad. I didn't grab a picture of it but it's nowhere near playable.

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The frets are a bit worn but not really screaming for a reset. But the inlays are screaming for a fretboard planing.

You can see the finish on the top is in pretty bad shape. There are several places where the finish has been scraped away and bare wood is exposed. Also there's a variety of dings and stains. And there's cracks, cracks, cracks.

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This is the most obvious of the structural damage. The bass-side F-hole is being held together mainly by the cloth back underneath. Completely unstable.

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Here is a more interesting crack on the bass side of the waist. This is a deep groove. I don't understand how this could be caused. In any case, it's very stable.

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There's also a minor split in the top behind the bridge which appears stable.

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In the image above you can see every crack I identified on the top (with pieces of tape). The split in the middle of the top turned out to be pretty serious. This was clear once the neck was removed:

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This split runs all the way to the neck block. It's movable with a little bit of force. Not good.

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A closer look at that F-hole. You can see the cloth backing that is holding the pieces together. I got some wood glue into the cracks and a little superglue underneath to hold the backing.

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A little clamping and wiping off of excess glue and it's done (hopefully).

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The split behind the bridge I filled with thin and medium cyanoacrylate. I had to switch to medium because it kept wicking away. This will hopefully keep the split from ever growing. I'll use a similar approach on the major top split, but use wood glue where the split is wide enough to get it in there. Ideally I should put a cleat on the back of these splits but that would involve removing the back of the guitar or doing some acrobatic clamping.

With all the cracks stable I don't have to worry about pressing too hard on the top and shattering it. So now I can get to cleaning this thing. A wet sock and some polishing compound turn this:

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to this:

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The difference is subtle but it turned out a lot of the nastyness of the top was just dirt and grime caked onto it.

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A shot of the whole top. All the cracks are stabilized and the finish is as good as it's going to be. I've considered refinishing the top but haven't decided yet. Except for the places where there is no finish at all it's really not that bad.

There's some really odd curvature on the back of this guitar. It's a difficult thing to capture in a picture but there is a big scoop in the middle towards the neck.

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Actually, what really is going on is the back is bulging out from either side of the neck block. If you peer inside you can see the back is peeling away from the neck block a little on either side of the block. I'm not sure what caused this or what could be done about it, but I'm leaving it alone.